'93 Transmission Doesn't Want to Up-shift.

[(insert name here)]

I started to type a really long story for the post, and realized that would probably just be tedious to anyone trying to read it, so I'm changing it to a basic facts post instead (still fairly long):

• My '93 Roadmaster recently started having issues shifting up out of first and second gear (first especially).
• Once up to third gear, things seem to work as normal.
• The normal engine speed on my Roadmaster prior to my problem was between 800 and 1200 RPMs. Now it often gets as high as 1600 to almost 3000 RPMs (I realize many other cars operate in the 1500 to 2500 RPM range on a regular basis, but I've driven this Roadmaster enough to know that's not how it worked before).
• I'm not a lead foot, so it's not like the engine is revving so high because I'm accelerating like a madman all the time.
• The car is not low on transmission fluid, and the transmission isn't slipping because it will still take off normally if I give it a good amount of gas.
• If the car refuses to shift up and I punch the gas for a split second, this seems to sometimes make the transmission jump up into the correct gear.
• Prior to this, two things of potential significance happened:
  • We had a snowstorm with about a foot of snow in the streets. On multiple occasions, I had to floor it for extended periods of time to be able to build up momentum and push through this snow from a dead stop (and yes, I know how to drive in the snow; these were odd conditions where the only thing even slightly effective was going full throttle). I also had to rock the car at one point (which I hate doing because it involves rapidly shifting between reverse and first gear).
  • Immediately the next day (i.e., before I had a chance to drive the car on plowed roads to notice any potential damage from the snowy conditions) I unintentionally overfilled the transmission by more than an inch on the dipstick and then drove about 130 miles on the highway (the transmission fluid has leaked since I got the car, so I regularly check it and add to it, especially before long trips). I noticed a slight problem shifting up on the way out of town, but once I hit the highway I had no more issues until I arrived at my destination and started traveling at low speeds again, which subsequently resulted in the car shifting up far later than normal. I rechecked the fluid, and at this point saw it was overfilled. I drained the fluid to the normal level using the top coolant line into the radiator and noticed little improvement. When I took the 130 mile trip back home, I once again had no problems at highway speeds, and only started having issues again when I arrived back in my hometown and had to slow down.
• I took the car to a transmission shop for a free computer scan, and they told me the car's transmission had no computer and the only way they could diagnose things was to service it and charge me. I do my own mechanical work and don't like giving people money, so I took the car back home.
• The transmission does have a speed sensor on the tail end of it, but the above incident implied to me that data from that sensor is only used to tell the engine's computer things, and thus it cannot be the problem with the transmission.
• I'm currently in the process of changing the filter (which has turned into a huge ordeal instead of being what I thought would be an hour job), but have given up for the night. I'm posting this message now, so that if changing the filter doesn't help, I can see if anyone has any other directions to point me. I did notice several electrical wires running around inside after I got off the transmission pan, so I'm a bit confused about what these are for given that the transmission supposedly has no computer-controlled components.
• I have already opted not to do a full flush on the transmission (which I was initially going to do this morning) based on seeing many people say online that flushing an old transmission that's been running on the same gummed up fluid for years can actually throw everything out of whack and kill it even faster. The transmission fluid I've gotten out doesn't look ridiculously old, but I was unable to find any record of the transmission ever being serviced in the paperwork I got with the car, so I figured it was best to start simple and just change the filter. I guess it's also conceivable that the transmission's been "flushing" itself for quite some time by constantly leaking and needing to be refilled.

So, questions:

• Does anyone have suggestions on what the problem is if changing the filter doesn't fix it?
• Might it still be something electrical (even though I dismissed that thought after the transmission shop said there was no computer to diagnose) such as the speed sensor or maybe a solenoid?

And to those who have removed their transmission pans before:

• For the love of God, please tell me there's a trick to get at those two bolts on the pan hidden above the stupid cross-member bracket thing that covers them up and prevents you from being able to stick a wrench on them! I managed to get them off after much wasted time, improper tool use, and forearm pain; but now I'm dreading having to put them back on.

 

[buickwagon]

The 93 is indeed an all mechanical transmission -- the electronically controlled version did not make it into the B bodies until 94. The first thing I would do is check the TV cable adjustment -- the cable links the throttle to the transmission and controls the throttle/shift relationship by modulating the line pressures within the transmission. IIRC, the cable is adjusted by releasing the ratchet mechanism by pushing the tab then moving it away from the throttle body until it stops. Then depress the accelerator fully so that the ratchet extends the cable at full throttle.

Also, check the cable for any sign of binding or sticking. At this time of year, it may even be frozen and not moving properly.

 

[(insert name here)]

I realize this isn't the best picture, but is this the cable you're referring to?

There does seem to be a tiny bit of slack in it if this is, in fact, the right cable.

Before I let the car back down when I finish replacing the filter, is there anything underneath that I should check or would all diagnostics be done under the hood?

 

[(insert name here)]

I tried replying to this thread a few hours ago, and the forum wouldn't let me. So I'll give it another shot now:

I have finished changing the transmission filter, and can confirm it didn't help in the slightest. I would like to post a picture to confirm the cable I'm looking now is the throttle valve cable, but I suspect that was why I was not allowed to post my previous message. My previous post might be awaiting moderator approval at this time, but since I received several different messages from the forum in the process of trying to post, my post may just be lost in cyberspace. So in the meantime, I'll try to describe the cable I'm looking at to see if it's the right one. There is a lever on the driver's side of the throttle body (or whatever the fuel injector equivalent of a carburetor is called). This lever has three lines attached to it. The top one goes through the firewall, so this is presumably the cable connected to the gas pedal. The second line runs to the cruise control module. Then the bottom line runs down along the firewall toward the passenger side of the car. This bottom line is an exposed metal cable with a little metal crimp connecting it to the lever and a piece of rubber several inches toward the firewall. This piece of rubber can freely be slid up and down the line, which I assume is not its correct function given that it looks like it's meant to be a stopper. If this bottom line is, in fact, the throttle valve cable, I'm not sure I understand your instructions on how to adjust it, buickwagon. There was a square piece of plastic close to the firewall that the line runs through that looks like it may have a tab on it, is this what I need to adjust? Could the lose piece of rubber be causing problems?

 

[buickwagon]

Sounds like you found it. Have a look at this website:

http://www.cpttransmission.com/tech_tvcable.htm

Click on the "tech 1" link for some diagrams.

Google found some youtube videos too, under "700R4". The 4L60 transmission in your car is identical -- literally. GM just renamed it.

 

[(insert name here)]

Well, the cable seems to be fine. It's tight at full throttle and snaps all the way back when the throttle is released. Despite snapping back all the way with no throttle, there's not a lot of tension at that point, but a couple sources said this was normal. I'm hesitant to make any adjustments for a couple reasons. One, multiple sources have said that adjusting this incorrectly could cause permanent damage to the transmission, so if this isn't the problem, I'd hate to adjust it and then make it a problem. And two, I've found multiple ways to supposedly make the adjustment, some of which say that people adjusting it a different way are screwing things up severely. So I'm kind of at a loss on which source to trust at the moment.

Google found some youtube videos too, under "700R4". The 4L60 transmission in your car is identical -- literally. GM just renamed it.

I kept finding information about the 700R4 and thinking that it wasn't the same as my car. Why would they change the name of a transmission without changing the configuration? That makes absolutely no sense, and is frankly just stupid.

 

[HotZ28]

We had a snowstorm with about a foot of snow in the streets. On multiple occasions, I had to floor it for extended periods of time to be able to build up momentum and push through this snow from a dead stop (and yes, I know how to drive in the snow; these were odd conditions where the only thing even slightly effective was going full throttle). I also had to rock the car at one point (which I hate doing because it involves rapidly shifting between reverse and first gear).

Stretched, or a disconnected TV cable from the shift valve will cause a similar problem.

Function of the TV Cable: Many people believe that this is a detent downshift cable and that this is the only function that the cable performs. In actuality, the TV Cable controls line pressures, shift points, part throttle downshifts and detent downshifts. The cable functions similarly to the combination vacuum modulator/cable systems found on other automatic transmissions.

http://www.monstertransmission.com/...e-TV-Cable-Adjustment-Instructions_ep_62.html
If the cable seems loose at closed throttle, check the cable connection to the shift valve first:

 

[(insert name here)]

Alright, I found enough sources describing the same method to adjust the TV cable that I felt confident that I could trust that method. I also noted the position of the slider so I could put it back where it was before if the method screwed it up. I tried it once and ended up with the slider being one notch (about a millimeter) off from where it was when I started. I took the car for a test run and saw no difference. I tired adjusting it one more time and ended up with it being in the exact same spot it was when I started. Took the car for a test drive for the heck of it and, surprise, there was no difference. So if the TV cable is at fault here, it's because it is faulty and not because it's improperly adjusted.

Stretched, or a disconnected TV cable from the shift valve will cause a similar problem.

If it's stretched, using the proper method to adjust the cable would then recalibrate it to compensate for the now slightly longer cable, correct? (If not, then what's the point of having an adjustment at all?)

If it's disconnected, would the car even be able to shift beyond first gear? I would think that with the cable disconnected, the transmission would simple think the car is always sitting with no throttle.



Also, while I had the transmission pan off this weekend, I did notice a few electrical wires running around inside the transmission. What might those have been for? I saw one video on assembling a 700R4 that said the wires ran to a temperature sensor that allowed the torque converter to engage when operating temperature was met, but (1) is the torque converter not engaged as soon as I shift into gear and (2) doesn't that suggest that the transmission is computerized if it's reading data from sensors and then executing physical commands?

 

[buickwagon]

The 700R4 was renamed 4L60 to bring the nomenclature in line with the system used to describe their newer transmissions. Stupid? Maybe, but they wanted a consistent system.

The transmission will shift early if the throttle setting is minimal. My 4L60E will be in 4th gear by the time the car hits 40 kph at minimum throttle. On the other hand, it will still be in 2nd at 100 kph if accelerating hard. Now, in the E version, the shift points are completely computer controlled. That was not an option on transmissions designed prior to the advent of PCMs.

Instead, your transmission shifts based on line pressures. The purpose of the TV cable is to modify the pressure based on the throttle setting. When you depress the throttle, the TV cable moves a spool valve to raise the line pressure and delay the upshifts proportionally. Or to initiate a downshift if the throttle is tromped while driving.

A loose (or inactive) TV cable will not move the spool valve sufficiently, shifting will be late and undue stress placed on the transmission at a time when the transmission oil pressure is reduced. Remember, the tranny oil not only controls shifting, it also lubricates all the moving parts, so high loads + low pressures = potential transmission damage. A tight TV cable will delay shifting. Engine RPM will be inordinately high for the vehicle speed. OTOH, at least the pressure is there, keeping the moving bits from rubbing together.

The adjustment procedure I described is as specified in the factory service manual. It ensures that the spool valve is fully extended (pressure at maximum) at full throttle. Assuming the throttle cable is not stretched to the point where it can no longer fully open the throttle.

If the cable is retracted but the throttle is not fully depressed, the transmission will shift late as the cable will be pulling on the spool valve early compared to throttle setting. Similarly, if moisture in the cable freezes, preventing it from fully retracting after throttle application, the shifting will be late as the spool valve will be partially unseated at all times.

Conversely, if the cable is stretched or detached, the transmission will shift early and will not kick down. And may be damaged as a result. Given the symptoms, I do not believe this is your problem.

And yes, to answer your question: Under normal circumstances, the adjustment procedure will accommodate cable stretch, as there is additional adjustment built into the system.

Torque converter basics: The torque converter is basically two turbines (think: fans for liquid) facing each other. One is connected to the engine, the other to the transmission. When the engine driven turbine "blows" fluid against it's counterpart, it tries to turn the transmission input shaft and hence, move the car. If the car is in park or your foot is on the brake, etc., the engine does not stall because there is no physical connection between the engine and transmission. The difference in speed between the engine and transmission sides is called "slip".

There is still some slip even under light throttle at highway speed. This is inefficient and serves only to convert engine horsepower into heat inside the torque converter. So, your torque converter has a special mode called Torque Converter Clutch Lockup -- a clutch inside the torque converter that can lock the two turbines together and eliminate slip when appropriate. Of course, we don't want the torque converter to remain locked when we apply the brakes, so the fluid pressure that applies the TCC is electrically controlled and connected to the brake switch on the pedal. Those are the wires you saw inside the pan.

The slip at light loads on the highway is normally only a few hundred RPM. It is unlikely that TCC lockup failure is going to have the engine revving at 3,000 rpm on the highway but could well explain 1600 rpm. It is possible the brake switch is set a little over-sensitive and not always allowing TCC lockup. You mention that the problem was primarily at times when you were slowing down, presumably tapping the brakes from time to time in the process. Perhaps the tap on the gas pedal was sufficient to jostle the brake switch. So it might be worthwhile to investigate the switch, which is also mounted on a ratcheting mechanism for adjustment. You could connect an ohmmeter or test light and verify that the switch works reliably.

Otherwise, the only possibilities that come to mind are all internal transmission problems. 3,000 rpm in 4th gear suggests a worn-out band (and probably other worn internal components). How many miles on the tranny? -- they don't last forever. The TV plunger could be sticking. There are various other internal control valves that can reduce line pressure as they wear and start leaking. You could try getting a transmission pressure gauge with a 7 or 8 foot hose off eBay and compare the line pressures to the FSM values while driving at different throttle settings and speeds.

 

[(insert name here)]

You mention that the problem was primarily at times when you were slowing down, presumably tapping the brakes from time to time in the process.

To clarify, my vehicle shifts incorrectly as slow speeds, not while slowing down specifically. When accelerating from a dead stop, the car stays in first gear much longer than it should. It will also usually stay in second gear longer than it should. Once I've reached third gear, things typically work correctly beyond that point.

Occasionally the shifts from first into second will be near correct (but still a little high), and the shifts from second into third will be at the correct time. Other times the shift from first into second will be so delayed that the car jumps from first to second to third almost instantly because I've managed to pick up so much speed in first that I should have already made it to third gear. And very rarely, the car will stay "stuck" in second gear well up into fourth gear speeds (and not because I've have the pedal to the floor and am engaging the "kick down" gear). I mention these three examples mainly to illustrate the randomness of the bad shifting.

Similarly, if moisture in the cable freezes, preventing it from fully retracting after throttle application, the shifting will be late as the spool valve will be partially unseated at all times.

This seems to be my problem (if it is, in fact, a TV cable issue). I would rule out ice as the cause since we had a couple warm days well above freezing this weekend and the problem still persisted, but if there is some sort of burr in the cable that catches as it's retracting (but not as it's being pulled out) it would cause the same effect. As stated above, basically once I reach a certain speed, things usually start to act normally. To state this another way (using arbitrary values for the sake of an example): The cable cannot retract to anything less than 40% throttle. Up until I have depressed the throttle 40%, the shifts are higher than expected. But once I pass 40% throttle, the linkage on the throttle body then grabs the now tight TV cable and pulls it onward as normal, thus giving proper shifting beyond that point. Leaving my example now, I will state that visually the cable does seem to retract fully when viewing the end attached to the linkage on the throttle body.

So it might be worthwhile to investigate the switch, which is also mounted on a ratcheting mechanism for adjustment. You could connect an ohmmeter or test light and verify that the switch works reliably.

Would this brake switch happen to be the same one that activates the brake lights? If so, I could simply monitor them for any abnormal behavior.

Torque converter basics: The torque converter is basically two turbines (think: fans for liquid) facing each other. One is connected to the engine, the other to the transmission. When the engine driven turbine "blows" fluid against it's counterpart, it tries to turn the transmission input shaft and hence, move the car. If the car is in park or your foot is on the brake, etc., the engine does not stall because there is no physical connection between the engine and transmission. The difference in speed between the engine and transmission sides is called "slip".

There is still some slip even under light throttle at highway speed. This is inefficient and serves only to convert engine horsepower into heat inside the torque converter. So, your torque converter has a special mode called Torque Converter Clutch Lockup -- a clutch inside the torque converter that can lock the two turbines together and eliminate slip when appropriate. Of course, we don't want the torque converter to remain locked when we apply the brakes, so the fluid pressure that applies the TCC is electrically controlled and connected to the brake switch on the pedal. Those are the wires you saw inside the pan.

I knew the information in the first paragraph, but I was unaware that automatic transmissions had a method of mechanically connecting to the engine. I thought automatic transmissions were never connected to the engine in any way other than the fluid, so it's nice to know that when I'm cruising at steady speeds the transmission actually does lock to the engine so that I'm not always wasting power with the fluid transfer method. Was this a relatively new feature in automatic transmissions at the time, or could I expect to see torque converter clutch lockup in '80s, '70s, and even older automatic transmissions?

How many miles on the tranny?

The car has just under 150,000 miles on it. I assume this is the original transmission with the same number of miles.


If I've not said this yet, the engine feels like it's giving the same amount of power to the transmission as before (i.e., no increased slippage); it's simply not shifting at the correct times.

 

[HotZ28]

The cable cannot retract to anything less than 40% throttle. Up until I have depressed the throttle 40%, the shifts are higher than expected. But once I pass 40% throttle, the linkage on the throttle body then grabs the now tight TV cable and pulls it onward as normal, thus giving proper shifting beyond that point. Leaving my example now, I will state that visually the cable does seem to retract fully when viewing the end attached to the linkage on the throttle body.

The link below is about the best description of TV function & adjustment I have ever seen.

Throttle Valve Cable system 101

 

[buickwagon]

To clarify, my vehicle shifts incorrectly as slow speeds, not while slowing down specifically. When accelerating from a dead stop, the car stays in first gear much longer than it should. It will also usually stay in second gear longer than it should. Once I've reached third gear, things typically work correctly beyond that point.

Ok, well it's not the TCC lockup then. That only occurs in D and OD. It was a long shot anyway -- I just thought the problem might have been related to accelerating after braking.

I mention these three examples mainly to illustrate the randomness of the bad shifting.

I'm not a transmission expert, but to me this sudden, random, shifting suggests worn or dirty internal control parts (eg: TV spool valve, pressure regulator, control valve or maybe a ball check) that are sticking and thereby affecting the pressures.

I would rule out ice as the cause since we had a couple warm days well above freezing this weekend and the problem still persisted,

So much for that idea then. You seem to be running out of external possibilities in a hurry. If you are seriously thinking of attempting this yourself, I strongly recommend you get a copy of the factory service manual for your vehicle. There is a lot of in-depth information in there about servicing the transmission. There are also a number of special tools that you will require (depending of course on how deep you go). First and foremost is a transmission pressure gauge.

Would this brake switch happen to be the same one that activates the brake lights? If so, I could simply monitor them for any abnormal behavior.

It will either be a completely separate switch, or at the least, a completely isolated set of contacts in a common switch body. I never had a 93 so I cannot say for certain. On my 92 (which is usually very similar), IIRC, there were 2 separate switches, one for brake lights and a second, with two independent sets of contacts, for cruise control and TCC, respectively.

I knew the information in the first paragraph, but I was unaware that automatic transmissions had a method of mechanically connecting to the engine.

Ignorance can be cured -- it simply means you have something more to learn. So forgive me if I say you exhibit some ignorance of the topic at hand. Are you really sure you want to tackle this yourself at this stage? I agree it would be a great learning opportunity, but how reliant are you on this car? Can you afford to make mistakes while learning? Or is this time to bite the bullet and hire a professional?

Was this a relatively new feature in automatic transmissions at the time, or could I expect to see torque converter clutch lockup in '80s, '70s, and even older automatic transmissions?

I'm not dead certain when the TCC made it's first appearance. Certainly by the 80's

The car has just under 150,000 miles on it. I assume this is the original transmission with the same number of miles.

My 92 required two rebuilds in +/- 400,000kms. I did a lot of towing with that vehicle, but yours may be coming due. It has been my experience that the engine was bullet-proof, the transmission is the weak link in the chain. If something internal is sticking, then odds are it's worn out (severely, all the moving bits ride in a pressurized lubricant after all) or something else has been shedding particles that were carried around in the lubricant until they found something they could jam.

The only other thing I can think of is a flush. But be forewarned: some people think a flush accelerates or exacerbates problems by relocating debris from innocuous hiding spots to sensitive spots like spool valves. So a flush may "fix" your problem (at least for now) or it may sound the death knell for your tranny.

 

[buickwagon]

I'm not dead certain when the TCC made it's first appearance. Certainly by the 80's

Working on curing my own ignorance, I found this on Wikipedia:

The first automotive application of the lock-up principle was Packard's Ultramatic transmission, introduced in 1949, which locked up the converter at cruising speeds, unlocking when the throttle was floored for quick acceleration or as the vehicle slowed down. This feature was also present in some Borg-Warner transmissions produced during the 1950s. It fell out of favor in subsequent years due to its extra complexity and cost. In the late 1970s lock-up clutches started to reappear in response to demands for improved fuel economy, and are now nearly universal in automotive applications.

- - - Updated - - -

The link below is about the best description of TV function & adjustment I have ever seen.

Throttle Valve Cable system 101

Parts 1 through 3 were a great read. I couldn't find part 4 though.

 

[krazykrames]

I thought I was on to something but after reading the rest of this thread it sounds like it may not be the issue after all, but, I'll share anyway.
One previously mentioned idea was the switch on the brake not working correctly thus not allowing the TC to lockup because it thought the brake pedal was being pushed down. In the other thread you started you mentioned that you no longer need to push the brake pedal down to shift out of park. Could this be the result of a bad switch?

ps.
On my 95 I don't have to push the brake to shift from park either, but everything else works fine. Oh and I can't manually put the shifter in first, the lowest the lever will go is second, but everything else really does work fine...

 

[(insert name here)]

I’m noticing now that sometimes it feels like I’m having to give the car a lot of gas to get moving from a dead stop, which would be a side effect of a greater problem than the TV cable. The car was kind of like this before, though, so it may just be the acceleration curve of this car combined with my imagination now that I’m paying more attention to my transmission.

Another thing I’m noticing is that once I finally get up into second gear, I can then slow back down and stay in second gear without the car dropping back into first before it should. This to me suggests a problem other than the TV cable system, since a flaw in that system should make it downshift too early as well, I would think.

I’m also noticing that sometimes the downshift into first feels pretty hard when I’m bringing the car to a full stop. This goes in line with a TV cable problem causing too much pressure at low speeds.

I also believe I found a donor vehicle for cheap should I decide I can’t repair this transmission. It’s an early ‘90s Chevy truck (a normal one, not an S10). It only has a V6 in it, but I do believe it has the same transmission that my car has (or if it’s not the same, one that will fit anyway). I’d have to do a bit of research, but even if the transmission won’t fit, I can still use many other parts of the truck to make it worth my time. Basically the net cost of the transmission in this truck is the same cost as a new TV cable (and this transmission will also come with a TV cable if I wind up just needing to replace that single component).

The link below is about the best description of TV function & adjustment I have ever seen.

Throttle Valve Cable system 101

Good stuff. The problem I was thinking I’m having (if my problem is TV cable related) is what the article calls “Long Spring Syndrome”. As buickwagon has said, I’ll definitely need a transmission pressure gauge to properly diagnose the TV cable system. Does anyone know how difficult it is to connect one of these things to a transmission that is installed in a car, rather than just sitting on a table? Keep in mind I have no dry/warm place to crawl under my car, so having to do that is always an unpleasant experience in the winter.

Also based on information in this article, I believe I can confirm the torque converter clutch lock up works correctly in my car. A few weeks ago (before I was even having transmission problems, actually) I inadvertently performed step 4 of this test. I lightly tapped the brake while in forth gear to see how overdrive would respond to this. I noticed that the moment my brake lights came on (before any real brake pressure was applied) the car’s RPMs promptly jumped up. I actually thought the car was automatically dropping down into third gear, but it seems this is a just the torque converter clutch “unlocking” and returning to normal operation, allowing for the bit of slip you normally get. Interesting stuff.

Ignorance can be cured -- it simply means you have something more to learn. So forgive me if I say you exhibit some ignorance of the topic at hand. Are you really sure you want to tackle this yourself at this stage? I agree it would be a great learning opportunity, but how reliant are you on this car? Can you afford to make mistakes while learning? Or is this time to bite the bullet and hire a professional?

I take no offense at your suggestion of my ignorance. If I knew how to diagnose transmissions, I wouldn’t be posting questions here. I consider myself to be fairly knowledgeable about cars (primarily old ones), but all my knowledge comes from experience with working on jalopies. I have yet to have a car with transmission problems, which is why I have no idea what I’m doing here. If this transmission is broken, I do want to take it apart and try to fix it so I can learn about it. But unfortunately, I am reliant on this car to get to work every day. My two other winter beaters are not currently fully assembled. Which is actually why I bought this car in the first place; winter began earlier than expected this year, and I didn’t have time to put either of my other beaters back together, so I promptly went out and bought the biggest cheap car I could find. So my situation at this point is that anything I do to the car must be completed within a two day period (the weekend). Obviously this means a transmission rebuild at home is out of the question right now.

It has been my experience that the engine was bullet-proof, the transmission is the weak link in the chain.

I’m a bit surprised by this. I expected the aluminum block engines in these cars to be pretty wimpy (not in terms of power, but in terms of durability).

The only other thing I can think of is a flush. But be forewarned: some people think a flush accelerates or exacerbates problems by relocating debris from innocuous hiding spots to sensitive spots like spool valves. So a flush may "fix" your problem (at least for now) or it may sound the death knell for your tranny.

I had planned to do a flush the day I changed the filter, and then decided not to after reading many people online claiming it could kill my transmission even faster if it was already beyond repair. But the reality is, the car was leaking transmission fluid so badly when I first got it (fixed now) that it’s probably already been “flushed” from leaking and needing to be refilled every couple days. Not willing to throw caution to the wind on this subject just yet, though, this does bring me to another question: I was advised to put some "Lucas Transmission Fix in with my regular transmission fluid to see if that could help out my bad shifting. But what I’m wondering is whether or not this would have the same supposedly deadly effect on my transmission as a flush would (since its purpose is to clean and dislodge gunk, just like the transmission flush).

One previously mentioned idea was the switch on the brake not working correctly thus not allowing the TC to lockup because it thought the brake pedal was being pushed down. In the other thread you started you mentioned that you no longer need to push the brake pedal down to shift out of park. Could this be the result of a bad switch?

The transmission issues began before I disconnected the park brake lock. The very same thought did cross my mind when I disabled it, though. Now that I know how to test the clutch lock up, next time I’m out on the road, I’ll see if unplugging the park brake lock had any adverse side effects. But from what I could tell, the wiring I unplugged did nothing but supply power to the lock.

On my 95 I don't have to push the brake to shift from park either, but everything else works fine.

If you're interested, I can take a picture of the park brake lock while it's both engaged and disengaged in my car. Not that it's a problem worth diagnosing, but it's always neat to see how things work. When mine was still connected, I could here a distinct click as it "unlocked" when I pressed the brake pedal.

Oh and I can't manually put the shifter in first, the lowest the lever will go is second...

That sounds like a completely unrelated problem. If I had to guess, there's probably just a broken piece of something inside of your steering column that's blocking the path of this component's rotation, or something at the base of the steering column that's blocking the lever that sticks out and connects to the transmission linkage. (This is based on the assumption that the steering column in these Roadmasters is the same as GM steering columns were back in the early '80s, which it looks like it is to me.)

 

[(insert name here)]

I don't particularly like double-posting, but I can't edit my previous post for some reason. I wanted to provide some closure to this thread by saying that my transmission is fixed. I was able to get it working again by doing absolutely nothing. We had another big snow storm and I had to do some more flooring of the car to get it out of some deep snow (just like I mentioned having to do in my first post right before the transmission got screwed up). Since that day the transmission has been working fine. Don't know if this was just a coincidence or if it was genuinely what fixed my problem.

 

[buickwagon]

My guess is that some dirt/debris eventually worked it's way out of a valve/passage somewhere. I think I'd be inclined to drop the pan and change the filter/fluid just to get it out of the sump.