Transmission/Motor Mount?

avtechwx3

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Hi Folks,

Here is what I've got: Start the Park Avenue in the morning, shift into Drive, and I get a bad bang. Funny thing is that this only happens upon cold start I guess due to higher rpm and smooth when driving. Its only when I shift into drive in the morning. When I got it inspected, guy told me I needed a mount. What does this specifically sound like to you and how do I identify? This is not something I will do myself because I've never done it before and don't want anything hitting the ground. At the same time, I am not going to let a guy replace all the mounts when only 1 is bad.
Thoughts?
 

Alan 55

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I have a 2001Park Avenue which should be very close to your 2000 as far as mounts are concerned. When you raise the hood the front mount on the right can easily be inspected for excessive movement. Two people are required, one observer and one person in the drivers seat. The observer will stand over to the side of the vehicle a safe distance but still able to observe the mount/engine. The person behind the wheel will shift the vehicle from forward to reverse, back and forth a few times holding the brake for safety.
Some movement of the engine/mount should be expected but only a reasonable amount. If the engine is rocking back and forth the mount is bad.
In my opinion the front mount that I have described is the mount that is most likely to give problems. Not to say that the other mounts can not fail because that is always possible.
If I were paying to have this done, I would do just the “primary” mount first and see if that solves the concern.
 

Drakito

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There are 4 mounts total. Alan is correct as the front is usually the first to go. However, the rear trans mount also can rip. The front is cake and takes less than 30 minutes with hand tools to change. The rear is a little harder and takes about an hour to hour and a half with hand tools. You have to jack the car up for the rear.
If the front is dead, the rear is either dead or almost dead. The rear has only a couple of inches before it will hit the rear part of the engine cradle, so your thunk is probably coming from there. The engine moves to the back under drive engagement and will compress.
Rockauto has both for a fair price.
The side mounts can go bad as well, but that is very rare. They are the "pivot" point for the engine and trans and are mounted along the center of gravity of the engine/trans combo and the bolt can be seen sticking down in both wheel wells. They are a much sturdier design than the front/rear.
 

avtechwx3

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Hi guys, thanks for the information. Would it be possible you can send me pics of the two transmission mounts you are speaking of? Much appreciated.
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Drakito

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Here are some shots of the front engine mount. I realize my engine probably looks different from yours. I have polished valve covers, a ported Gen V blower, intercooler, 4" intake, 8 rib belt conversion, 3" pulley, and much much more. The coolant overflow you see mounted by the radiator is for my intercooler.

I'll snap some of the rear mount when I get it in the air later tonight. My ICM just went out.
 

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avtechwx3

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Thanks much guys for the info, the pictures really help. So what your best guess is that it is probably the harder to get to mount due to the thud I am hearing? And yes, it is a loud clunk but why only in the morning and then it settles down even during that early drive? I was curious why it doesn't do it all the time if the rear
mount is bad?

I'll do the test Sunday looking at the front one and maybe I will do that myself. Do I need to support the engine when doing this or just replace?

Much Appreciated
 
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I would also think this would happen all the time, not just when cold. If it is really cold climate and the choke idle is real high, then maybe only when cold, But if the mount is bad you should be able to duplicate this effect at will, anytime you want to. This makes me think that maybe there are two different problems, and I wonder if there are any transmission issues that might cause a max pressure issue when cold or in neutral going into gear hard? A Valve Body issue, A fluid leak or bad gasket in the VB, sticking VB piston, sticking solenoid or pressure switch etc. Food for thought.
 

avtechwx3

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I would also think this would happen all the time, not just when cold. If it is really cold climate and the choke idle is real high, then maybe only when cold, But if the mount is bad you should be able to duplicate this effect at will, anytime you want to. This makes me think that maybe there are two different problems, and I wonder if there are any transmission issues that might cause a max pressure issue when cold or in neutral going into gear hard? A Valve Body issue, A fluid leak or bad gasket in the VB, sticking VB piston, sticking solenoid or pressure switch etc. Food for thought.
yeah, I know it sounds weird but i get the big thud when cold in the morning and then that is it, shifts good and smooth with no noise after. Was rebuilt a year and a half ago with no issues or leaks that I know of. Anything I should look for? Still under warranty until January so any ideas would help.
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Try letting it idle in neutral and then drop it into gear and see if it will do anything close to what it does when cold and going from park to drive. I am not all that skilled at transmissions but lately I have been doing a lot of reading about installing a Trans-Go Jr shift kit and along the way I have found a bit of info on operating characteristics as related to transmission problems but I don't know enough about the trans to have memorized all the diferent symptoms and causes. I just think it is worth checking into because that symptom seems familiar, like I read about something that sounds along those lines. I will spend a little time trying to see if I can find info on trans symptoms and what causes them. I may have saved a page in my fav's that has diagnostics and symptoms but not sure. Again, I will check and see what I can find.
 
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It has been my experience that a trans rebuild is usually anything BUT a "Rebuild" as most shops will tear it apart and fix what is obviously bad and then put everything else right back in. Then you will likely have issues down the road when something goes out that was near failure but not failed and reused. Just saying, IMHO new clutch discs and new gaskets is hardly cause to even use the word "Rebuilt", I had a trans once that lost 3rd gear, removed the trans myself and took it in to be "Rebuilt" picked it up and reinstalled, Worked fine for about a year and a day then it lost 3rd gear Again ! It was probably a sticking valve in the valve body or a bad seal on the 3rd gear piston in the VB and they likely only cleaned it, checked for free movement and reassembled. Made me wonder IF I even got new clutch discs in that "Rebuild" but after that I swore I would never use that shop again.and only use a shop that specializes in a certain brand GM Ford Mopar etc even if it meant I would have to ship it to them. Rural Iowa doesn't have a lot of good shops to choose from lol.

I found a list of 30 different symptoms that won't kick a code and number 18 was the one that sounded familiar.

18. Extremely harsh shifts from P or N, normal shifts at WOT: EPC (Electronic Pressure Control) solenoid failed.. Fix as soon as possible or hard parts will eventually break.

It could be that it is Just a transaxle mount, but better to check into all possibilities for that symptom. If you have a code reader you might check for any codes just in case

Also, if you change your own trans fluid and filter, then you likely have the tools and skills necessary to replace that front mount. All that is neded is a jack and an foot long piece of 2X4 to place it under the trans pan from front to rear at the far drivers side. It is actually pretty easy to get at since it is right in front and you can accsess from the top and bottom. Save the labor cost and swap it out yourself I just did all of the mounts on my 94 and I used a DEA front mount and if I had to do it again I would use a Westar because the bracket on the DEA mount was poorly done and was hard to line up. Mine has that ridiculous looking little shock absorber built into the mount. If you do the rear mount it is a bit tougher to get at, but still totally do-able for a DIYer.and I think the 2000 model has a different style mount than the older models which can only be a good thing and I think I know why the design changed LOL.
 

avtechwx3

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thanks for the replies, good stuff. Yes, I had the transmission rebuilt here in lower NY, not the city, suburbs right above, at a shop that is independent of any franchises. I had to work to find one beost of the old timers are not around anymore and what we've got here is pretty bad. AAMCO that really rips people severely, check out the AAMCO complaint site and you won't believe what you are reading, and other shops that just aren't that good. Transmissions have gotten a lot more complex as well but I mean do you know what you are doing are not? And a lot of these guys do not so I completely agree with you. Its a national problem and the same everywhere which is why so many people will not take that step. John at CityWide in Yonkers NY knows his stuff and his reputation is that stuff doesn't come back for a long period of time. If I could get 10 years, 100,000, I would consider that a miracle in today's environment or even 7 and 70 would be very good. My mechanic does not believe in rebuilds, only remans which are as close to new as possible. John will rebuild German transmissions for people who are paying 8 thousand at the dealer, he does it for six or a little less and the flock to him. I checked out a different guy before I took the Park Avenue to John. This guy was wearing an AAmco shirt and I didn't use him which I found funny. He had a Range Rover in there worth 100 grand and told me the rebuild was running 14 grand. Holy Cow!

And no, no codes whatsoever. I also agree that I couldn't figure out why the shabam was only upon cold start and no other time. I thought high idle but it will not do it again throughout the day, only when cold. I have never done mounts, I do about 70 percent of my work. I asked my mechanic and he wanted to do all four for 1,100 and I'm like c'mon dude, all four? The two near the wheel wells don't need to be done, they hardly ever go. I have one real problem and I'm pretty sure its the one near the firewall. He wants over 400 to do that and with the one in the front, just over 600. I mean if that doesn't solve the problem, it would have to point to the issue you mentioned? I'll check fluid for leaks and let you know.

So the main question from all of this is: Is it just a mount or could it be the second attached problem of high trans pressure due to a pressure solenoid?
 
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YIKES !! $1,100 to do 4 mounts ?? I think I'd spend as much time searching for a mechanic as you did for a trans remanufacturer. That sounds like a Really high price to pay for labor on mounts, even if it includes the mounts. I could probably get all the mounts for under $100 for parts (Rock Auto) You have to shop around and compare the base price against the different shipping charges but it is worth the effort. Ebay prices that include free shipping are generally a little higher than Rock Auto, but not by much and Rock Auto does combine shipping to a certain degree but because some parts come from different warehouses they can't do it all the time. But if you aren't picky as far as the brand you can try to get all of them out of the same warehouse, then you save good on the shipping.
I would suggest talking to your trans mech and explain in great detail what it is doing, he might know exactly where to start looking.
Myself I don't know a lot about transmission behavior as far as what might cause things. I'm like everyone else, I usually steer clear of them whenever possible.
Like I mentioned before, if it were ONLY the mount, you would hear it all the time or at least be able to duplicate this THUNK whenever you wanted to. So YES there is likely something else going on besides just the mount and I imagine it has to do with fluid pressure when cold but what is causing that could be a stiff seal or a flattened out o-ring or a sluggish valve body piston or even a failed spring in an accumulator somewhere or even a gasket that is allowing fluid to "blow-by". I doubt it will be a major malfunction, just an annoting symptom that might lead to other things if it becomes more pronounced with advancing deterioration of the affected part or seal.
Try letting it warm up for a few minutes and see if it still does it. Try putting it into neutral for a few seconds before going to Drive and see what happens. Take notes on everything you try so that way when you take it to your umcommonly competant trans mech he will have some good information that might lead him directly to the cause.
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For a pro mechanic that front mount should only take about an hour, so even $200 for swapping it out is Real high. I pay my mech $50 an hour, not $200 an hour. That is another good reason I say DIY. If you do 70% of your own repairs then this should not give you any challenges beyond what you have already experienced. The rear mount is more challenging only because it is a tight fit and hard to get your hands and even tools in there, but the newer mounts have a different design than my 94 had so it might be a little bit easier than what I went through. YouTube is AWESOME for repair how-to videos to let you see what is involved, some videos are definately better than others so watch a few different ones if there are several available. You will see, it isn't that tough and being armed with the how to video it just makes it that much less a mystery.
 
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And now that I am really thinking about it, through all of my research on installing this pesky 4T60E shift kit from TransGo, I did read somewhere that there is a temperature sensor attatched to the pressure solenoid that creates max pressure until the sensor picks up that the fluid has reached operating temp and then it opens a different route for the fluid to flow so I think that the number 18 on that "list of symptoms that won't kick a code" is very very likely to be your issue or at least have something to do with it.
Think of it as route A (Cold) and Route B (Warm) that the fluid flows. Now there could be a half dozen reasons why the fluid is taking rout B before it should. Could be the solenoid, Or the temp sensor, Or a failing gasket allowing fluid blow-by, Or a stiff, flattened or otherwise failing seal or o-ring, Or a weak or broken spring (If there is ine in that route), Or something clogged in an orifice or filter (If there is one in that route) Or maybe even a deteriorated coated plastic check ball (If there is one in that route) Etc. Etc. . But I do believe that the problem is in that general area of the switching between route A and route B
 
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One last notion. Let it warm up for 10 minutes before you shift into gear, I am betting it won't BANG anf that will be the proof in the puding.
Also Beside trying different things, and taking notes to see if it still BANGS under different circumstances I would definately let the vehicle warm up completely before leaving the driveway every day, because as Number 18 states "Fix as soon as possible or hard parts will eventually break"
What that means in your case, is that if you just let it go it will eventually cause MAJOR Damage, but likely NOT until after January and then you'd be properly BONED on your warranty!.
 

avtechwx3

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Thanks much Guido 1, I will do that warm up test, and give John a call. I'll let you know. Again, thanks for the info on this, I really appreciate it.
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Hello,

I did the warm up test over the last two days. First time for ten minutes and still banged hard into gear. On Saturday, let it warm up for 15 minutes and the hard bang was much less harsh and by 20 and up hardly at all if at all. Keep in mind that temps here in lower NY are in the 55 to 60 range so ten minutes might have done it earlier in the week but it took 15 to 20 now.

So that should be it then, it has to be something with the unit itself not the mount. I mean, the mount might not be great but this must prove that the actual problem is with the transmission?! My thought is to get it to John while it is still under warranty until January and let him keep it overnight so he observe for himself how it shifts for the first 10 to 15 minutes and then after that.

Any other thoughts would be appreciated.


Best Regards As Always
 
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Your mount could still be bad. The BANG as we now know is not caused By the mount, but likely the other way around and the bad mount might be caused by the Bang. Have your trans Mech check out the Mounts while he is inspecting and see what he says. They might not be Perfect, but might not need replacing either, hard to say. IF John says the Mounts are fine for another XXXX Miles, then it is definately time to find a New General Repairs Mechanic. Remember, "$1,100 to replace all 4 bad mounts", so have John check all of them out just for a 2nd opinion. It could be a telling thing about potential past Fleecings performed by the other guy.

If it is a daily driver and it is unavoidable, I would suggest putting a big piece of cardboard in front of the radiator with a smaller circle cut out of the middle area so it warms up faster in the cold weather. I had to do that with my Dodge work van during the winter in Iowa because my hotrod work rig had a 3 core radiator, a 180 deg thermostat, a high volume waterpomp and a high perf sheet metal flex fan.. I swear, I parked with my grille right up against the garage door and I could let that thing idle all day and it would never get warm. Even with the cardboard in front of the radiator it would stay cold until after I got out on the road and it never blew good heat through the vents. I built it to stay cool in the summer and it never went over 190 deg on even the hottest days, but there is an ice cold winter trade off LOL.
If you can find a way to slip it down behind the grille, in front of the radiator so you can get it in and out easily that would be great because then you could put a cardboard in with NO Hole Cutout and just remove it once it is all warmed up. Or for IF the weather gets warm enough to see the temp guage rise too high. A 3 to 5 inch diameter circle in the cardboard might do it. Remember the trans fluid has a real hard time warming up while it is sitting still, so the trans fluid needs to pick up heat from the radiator, so the faster your engine warms up, the faster your trans fluid will, so even with electric fans this should help to get you on the road sooner.


This is one of those occasions that I am real glad I was reading this post. It is all such a coincidence that I happened to read those symptoms while actually looking for something completely different and then just happened to see this issue. I would not have had a clue a couple weeks ago so this is awesome that it saved an $1,100 repair bill as well as potentially a busted trans next Feb. Wicked cool save !!
 
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I just had another thought, I wonder if you can beat the BANG to the Punch? Letting it sit and idle a few minutes gets the fluid pressure pumping and because of the trans fluid temp issue the pressure gets good and high.
Just for giggles try this:.
1 Set the Emergency brake,
2 Turn the key to the On position without starting it, just to get the shift lever unlocked.
3 Put it into neutral and Keeping pressure on the brake pedal,then
4 start the engine and Immediately shift to Drive and then slowly let off the brake pedal to see if the emergency brake is going to hold it. You might need to 2 foot it with the brake and gas pedal depending on how cold it is and how the engine runs when cold but if you can tickle the throttle just enough to keep it running then it might just work.
Then you can let the trans warm up simultaneously with the engine for a few minutes.
If it doesn't have a chance to BANG when you do this then you can get on the road quicker in the AM and might not need to use the cardboard to block airflow.
But if it sits all day and gets cold again, then you might have to repeat the morning process to keep it from banging.

It might be worth a shot just to see how it acts and to see if you can catch it before the fluid pressure gets pumped all the way up.
 
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