96 PARK AVENUE ULTRA: Transmission issue? P300 P705 P706 Help!

[96PARKULTRA]

96 PARK AVE SUPERCHARGED 110k.
-Bucking/stalling/shudder in 1st on accellaration & decelleration to & from a stop. Sporadic slippage.
-Also Waterpump leak
-Temp fine, oil fine, trans fluid fine
Codes: P300 P705 P706

Any recommendations????

The full story below for any helpful geniuses who are interested:

Moved to LA last fall and I bought a PA. Drove it for 3 months, everything was great. I did notice the coolant reservoir low a couple times, but never noticed any leaks on the ground. I obviously should have taken more attention to the slowly disappearing coolant. I'm not a complete idiot when it comes to cars, but I'm not knowledgeable enough to really fix anything either. I always just try to find a decent 3.8 that some old person drove & maintained for 100k or so. I get the oil changed ever 3k mi, check the fluids at least occasionally, & don't beat on it mercilessly -- but I don't baby them either. And, I will admit I was having fun driving this car a little harder than normal since I never had a supercharged 3800 before -- but nothing super abusive.

Anyway one day I'm mashing down the freeway at 80+, slow down on an off ramp to drop friend at airport & suddenly the engine stalls. Threw it in N & started right back up, but it kept bucking violently when slowing to a stop or accelerating from a stop. Had to throw into neutral and give a little gas when stopping. And likewise give a little gas & throw into gear to get moving again (to avoid stalls).

Never saw temp get hot & oil pressure gauge was fine. Got out of airport loop, checked fluids, Oil 3/4 qt low & little dark (it was due for a change anyway) but no water/milkyness, coolant reservoir low again but only took about half a gallon to fill back up, trans fluid red & clean & kinda thin, no leaks underneath, idled fine in park, no tailpipe smoke. So I drove several miles back towards home in stop and go. Anything over 10 mph and the car ran fine & pumped through gears at freeway speeds. But engine was shaking hard in 1st at low rpms & stalling. So I just stopped at first little rinky dink shop in my area (new to area, didnt know any mechanics). They had it for 2 days and best they could say was "IDK, maybe transmission." Well...Pep Boys was around the corner & i figured they might overcharge me, but at least they could scan it & figure out the issue, and fix it asap. At this point I noticed a water pump leak (it's intermittent). So Pep Boys does a diagnostic & tells me its a head gasket because they did a hydrocarbon test of the coolant & got 72 ppm. Plus obviously a faulty waterpump, and they said the radiator is "corroded". $2600 total. Obviously I'd just buy another car instead, so I limp it home. I was skeptical of the HG diagnosis, but I called a couple shops & they all said that HC in coolant is surefire proof, so I figured it was junk.

Once again, the codes they gave me were: P300 Engine Misfire, P705 Trans range sensor (prndl input), P706 trans range sensor out of range.

So the car sat for over a month cuz I was busy & didnt have time to investigate further. Then one day I start it up and surprisingly no more stalling, just a stutter in the same 1st gear rpm range at stop & go. So I drove it for awhile short distances on city streets & just kept topping the reservoir with water. The trans seemed slow to shift down on deceleration. When stopping fast it would kinda "clunk clunk" down.

So I stopped at another two reputable shops & they both test drove it quick and say "I think maybe trans". They both tell me to fix the water pump and just continue to drive it and see what happens. But I'm not gonna throw $400 at a $2k car when nobody can tell me what this other issue is. Transmission shot? Head gasket? Those are both "junk it and buy another one" type problems. And I'm not broke, so I have no problem buying another car if this one is junk, but for all I know it could be something minor (cuz none of these shops have given me more than a generic guess). I hate to junk the car over an unknown issue, but I'm in a spot where its not realistic to keep filling this reservoir constantly, and its stupid to fix the water pump if the trans or HG is shot. And it also seems stupid to pay any other shops for a diagnostic, because they'll probably be just like Pep Boys and tell me I need a Tranny or HG when they can't figure out the specific cause.

Then finally today after two weeks of short trips in the area, suddenly the transmission was acting very smooth, practically like normal. So I took it for a few couple mile spins back and forth on the freeway, getting on the gas, pumping through gears like a suburban race car again. Then on my third loop back home I get off the freeway and suddenly its real weak even in 2nd & D, spongy pedal. Trans seemed to be slipping. Had to shift down manually to get decent propulsion. Barely could make it up my driveway incline cuz 1st gear was slipping so bad. Something smelled kinda burnt. Never was like this before. Gauges weren't hot, oil pressure still normal, & reservoir was almost full of water. Let it sit for 30 min, then another spin around the block and it was shifting again (altho very poorly), and still alot of slippage & weak power. Now it'stime for sleep. I'm gonna see how it wants to act in the morning and swing by a transmission specialist who does free inspections for one more opinion.

I don't know what to do at this point. Is it likely the trans itself is going out? Or possibly a sensor or something else minor instead? Lately the engine seems to be a little louder / rougher sounding than normal. Sounds like there is a bit of a wiz/whine/grumble somewhere that I don't recognize, but not loud enough for me to pinpoint precisely. One other important note is that there is sporadically some water spray from that pump leak that drips on the belt and gets thrown up to the top of the motor, so that's why I hypothesized a sensor/elec issue is a possibility. Adding to the pickle is that almost everbody in LA drives foreign's, so these mechanics see PA's so rarely that I doubt they have the experience to spot common issues. Closest GM dealership is 20+ miles out in the valley. Called a couple dealers & unsurprisingly, they didnt care much to give me any worthwhile pointers for an 18 y/o car.

I love the car, and there's almost none for sale out here to replace it. Figured I'd try here for last ditch recommendations?? Thanks.

 

[Ziggy]

You would have several problems. Slipping indicates a transmission problem. I would check the transmission fluid again for color and smell. When was the last time you changed the filter and fluid? However bucking and stalling has nothing to do with the transmission, but with an ignition or fuel problem. What age are the spark plugs and ignition leads?
There are more knowledgeable people on this forum who will chime in with specific tests and procedures for you to find the actual culprits, but they would need this information as well.

 

[96PARKULTRA]

I should also mention that the Service Engine light is not on. No idea on how old the plugs, etc are. Trans fluid is fine -- if anything it looks slightly thin to me -- but definitely red & at full level. I only had the car for a couple months before this arose, but it was working great until the sudden issue. So I understand how it's possible that I have both a major trans issue & an unrelated ignition issue, but it's extremely coincidental if it is. I did notice that 2 of the pins(?) the plug wires attach to were somewhat corroded. I cleaned them with some wd-40 and a rag, but need to go get a wire brush to really get it off. That's as far as I personally got into taking things apart, like I said, home repair is kinda out of my league. I'm just hoping somebody has had a similar issue and can give me something to check or recommend to a mechanic. If not, my next best course of action seems to be a hope & a prayer & some Trans additive like Lucas?

 

[Ziggy]

I wouldn't call it extremely coincidental. The car is 18 years old and unrelated things break down all the time simultaneously which make it difficult to distinguish and troubleshoot I can tell you from experience...
I think it is time to get the spark plugs out and post a pic of the electrodes. Also if you have a multimeter check the resistance of the ignition leads and post it. These are simple things you can do yourself, and save a lot of money.
Also I wouldn't use any additive just have a new filter installed and fresh Dexron VI fluid. The VI is very important !

 

[FFarr]

Others on this forum more knowledgeable than me on the subject but I think a corroded coil terminal generally means defective coil/wire/or both.

 

[HotZ28]

Others on this forum more knowledgeable than me on the subject but I think a corroded coil terminal generally means defective coil/wire/or both.

Thanks Frank, that was exactly what I was thinking after reading post #1. If the coil/wire(s) were getting wet from coolant slinging under the hood, misfire would only be exasperated. I have seen weak/dead coils & wires give the same symptoms as a slipping trans (dead cylinders). One bad coil can cause a P0300 (Random Misfire). BTW, the P0705 & P706 is from the P/N switch which is unrelated to internal problems. In fact, those codes could have been stored several years ago and never detected until now. I do not think the OP has a trans problem.

 

[96PARKULTRA]

Thanks for replys.

Still horrible power/slippage today. I don't know if I messed something up yesterday, or if maybe something got wet again, hence the disappearing/reappearing symptoms that seem to get better by just sitting over time.

Attached photo of those 2 corroded terminals next to a clean one.

 

[96PARKULTRA]

Further update. Transmission still seems to be malfunctioning. Super late to shift, rpms will wind way up without shifting, until I let off and coax it to shift. Real hard shudder/slip climbing steep driveway in 1st (sometimes can't even climb). This new more serious symptom just started yesterday, right after the original low rpm 1st gear stutter issue completely stopped. Still possible to be just a coil/ignition issue?

I'm completely confused by the variety of changing symptoms here. All these mechanics want to do is get paid for a diagnostic & scan codes again, they don't want to listen to what I'm telling them about how it's been acting.

Also, am I dangerously risking overheating the trans by test driving it a few miles at a time with just water & a leaky/faulty water pump? My temp gauge stays right around 200 & I'm making sure to not run low on water.

 

[Spriteman]

Okay - so you're not good under the hood but, there are a couple of very easy tests you can do.

First, check the spark at the plugs, plug wires, and the top of the ignition coils using an HEI spark tester like this -

http://www.oreillyauto.com/site/c/detail/KDT0/2756/N0221.oap?ck=Search_N0221_-1_-1&pt=N0221&ppt=C0371


The thing about our cars is that the coils generate a very high voltage energy pulse to send to the plugs - if that pulse doesn't get into the 50,000 volt range the plug won't fire. That's the same as another car not getting a spark at all.

If you need specific help on how to do this just check back here.

Once you have the results for each of the 6 plugs let us know what you found.

You have to start eliminating problems somewhere and this is an easy place to start. And, if you find a bad coil then that's a very easy fix you can do in 10 mins.

All we can do from the forum is to provide ideas on what to check but if you can't do the checks yourself then you'll have to get it into a shop.

Good luck and let us know what you find.

 

[96PARKULTRA]

Totally understand. I guess my main objective here was trying to figure if the latest trans slippage/shifting issue was likely transmission deterioration vs. a sensor vs. ignition/coil (as mentioned by Hotz28). I really don't have a problem paying a mechanic if they're actually gonna figure out the issue. I just don't know a good one here & those I've dealt with so far haven't seemed sharp or honest enough to trust their opinions. They pretty much just want to charge for a diagnostic & tell me I need some major repair like a head gasket or tranny rebuild. (I doubt Pep Boys even drove it around the block, they never even told me I had corroded terminals.) So that's the pickle.

I think I'm gonna throw some Lucas in the Trans because if it works, then I know what the issue is. I'm just trying to avoid many hours & $$ trying to diagnose/fix a misfire, only to still have dead transmission.

 

[Spriteman]

Everyone here can relate to having to deal with a no-so-honest mechanic - so you are definitely not alone in that.

But, keep asking around - see if you can find a mech that left a GM dealer who's got the training but decided to open his own shop.

Let us know what you find.

 

[HotZ28]

Everyone here can relate to having to deal with a no-so-honest mechanic - so you are definitely not alone in that.

Not necessarily "no-so-honest mechanics" but the lack of knowledge & experience!

But, keep asking around - see if you can find a mech that left a GM dealer who's got the training but decided to open his own shop.

Good advice, but be sure to ask if they have experience with the Series II S/C engine before trusting their diagnosis. Knowledge & training varies with a particular engine and vehicles.

I just don't know a good one here & those I've dealt with so far haven't seemed sharp or honest enough to trust their opinions. They pretty much just want to charge for a diagnostic & tell me I need some major repair like a head gasket or tranny rebuild. (I doubt Pep Boys even drove it around the block, they never even told me I had corroded terminals.) So that's the pickle.

Pep Boys technicians should be restricted to changing tires! Most of them have just advanced from the same job at Wallymart for $1.00 more per hr. Head gasket failures are very rare on this engine. Has anyone preformed a coolant pressure test, or a cylinder leak-down test? IMHO, the advice you got so far is all bogus info!

 

[96PARKULTRA]

Yeah HotZ28. That's exactly how I've felt. All these guys want to do is read codes. I try to tell them what's going actually going on & they don't wanna listen. Hard to imagine anywhere in America where 3800's are rare, but nobody drives these cars in LA. About the only American car you see with any regularity is a Charger. There's not even a GM dealer within 20mi of my place. Plus nobody drives older cars out here.

If the transmission is going out, would it absolutely show a code for that?

 

[HotZ28]

If the transmission is going out, would it absolutely show a code for that?

Not necessarily, the PCM may not monitor internal pressure. If you are really thinking that you have a trans issue, you should take it to a reputable trans shop and ask them to do a pressure test. Before you plunge into a trans rebuild, please follow the advice already given in this thread. We are here to give free advice to the owners of Buick's, and usually do not offer bogus advice! If I had your car in my shop, the correct diagnosis would be free, and given in less than 30-min!

 

[96PARKULTRA]

Yeah, you guys def seem more knowledgeable & helpful than any of these local shops I talked to. But obviously you're not hear to test drive it. It suddenly isn't shifting correctly at all now. I totally was thinking it could be some ignition/elec glitch when it was just a stutter. But now all of a sudden it went from a little stutter in just 1st to a major slip in varying gears. It's like it's not even engaging the gears sometimes, just sits there and revs with no propulsion unless I downshift manually and coax it.

I'm gonna try some Lucas as a last resort. Trans level is currently just a hair above full, do I need to drain 24oz of trans fluid out, or can I just put the whole Lucas bottle in. I've seen people say both on the internet.

 

[HotZ28]

You could very well have a trans problem, but as mentioned, dead coils could give the same feeling & driving experience. From the appearance of the coil towers, you obviously you have a problem there. Good Luck!

 

[Cadillac_AL]

Could also be a MAP sensor. When the MAP in my 92 Caddy died I didn't get a code until the car was undriveable. It was stalling at redlights and shifting wierd. When I had another issue with the car months later, I put the old MAP in it for a test and the car wouldn't shift at all.

I don't quite understand the aversion to checking codes other than high cost at some places. I would be upset if a tech changed a bunch of parts without checking codes first.

I do thing a 96 ECM is much more advanced than a 92 ECM and should pick up a bad MAP faster than an older ECM. In any event, when it comes time to throw parts at it, a MAP sensor is as cheap as anything else. Good luck.

Edit. Oh yeah, my first thought was that this car probably sat around for a long time before it was sold to you. All the fluids should have been changed at that time for peace of mind. I always get a chuckle at all of our transmission posts here with no mention of trans fluid or trans maintenance. Not this post because OP said trans fluid looked thin with age unknown. Good luck.

 

[Ziggy]

I'm gonna try some Lucas as a last resort. Trans level is currently just a hair above full, do I need to drain 24oz of trans fluid out, or can I just put the whole Lucas bottle in. I've seen people say both on the internet.

If your transmission has a problem (and remember the people on this forum which are experts on the PA say you probably don't) I am extremely doubtful that any addition will cure this problem. I am willing to go out on a limb here and say it won't work.
However if you like this car and plan on keeping it, I would advise to have the transmission fluid and filter changed (with Dextron VI)
when you aren't sure when it had its normal maintenance. I can tell you right now that the last owner didn't do it before you bought the car. If your transmission has a problem due to a clogged filter or aged fluid there is an actual chance of improvement. If not, normal maintenance never hurts. Still it seems to me that you need to fix an ignition issue first before getting to the transmission.

 

[96PARKULTRA]

I tried the Lucas (it worked for my dad in the past) -- no luck with my car. Tried driving it to a trans shop for a final confirmation. Trans went basically all the way out en route. For some reason if i'd shut the car off, then start back up, I could get a little propulsion in first. Had to do that basically everytime I had to come to a full stop, just to get it back home. Trans fluid is still red, but it's overflowing out the dipstick is that normal for a dead trans?

Looks like it's time to call the junk yard. I'm glad I didn't fix that water pump. I had good instincts on this, always felt like a tranny to me. Certainly would have been happy to be wrong though...

 

[HotZ28]

Trans fluid is still red, but it's overflowing out the dipstick is that normal for a dead trans?

Yes, internal seal leaks (low pressure) will cause the clutches to slip, therefore creating excessive fluid temps which will cause boiling of the fluid. Did you notice any fluid flowing from the vent pipe on top of the trans? Sorry to here you have this problem with such a low mileage. I change fluid & filters every 30K, and use Amsoil full synthetic trans fluid. In addition, I installed an external fluid filter and cooler with a fan. I now have over 200K and the trans performs much better than when it was new.