: Transmission NIGHTMARE



J.A.O.
07-17-05, 10:09 PM
I was driving the car this afternoon and after paying a toll, I accelerated and noticed that at 65 mph, the rpm's were over 3000. I let off the accelerator and the rpms dropped back down as they normally do when you are in overdrive and let off the gas. I gently re applied the gas and the rpm's went back over 3000. The car did not shake or jerk, but in order for the wheels to receive power, the engine had to be turning much faster than normal. I was beginning to think that maybe I had lost overdrive. I continued with the cruise set at 55 and everything else (with the exception of the higher rpm's) with the car ran fine. Then about 20 min, later without warning, the rpm's shot up as if the car had come out of gear. I put my foot on the brake to disengage the cruise and stopped the car and shut it down to call a tow truck.

There were NEVER any warning messages displayed, the car did NOT overheat, and there was never a warning light. I checked for codes, and there were NONE. After I pulled over I tried looking for any fluid leaks and found nothing. I'm stumped as I am starting to believe this might be a mechanical problem since the computer seems to have no knowledge of this (no codes, no warning lights, NOTHING). Anyhow, the car is at the dealer and tomorrow I will have to tell them to figure it out.

I've had this car for 3 years and this is the first major thing I've had happen in the 46000 miles I've put on it since I bought it. To date, the car has 94000. I'm clueless and on the edge of my seat.

Any thoughts?????

Thanks Guys.



Jason

BeelzeBob
07-17-05, 11:47 PM
The most obvious thing is the shift solenoids failed. The trans defaults to second gear which is consistent with what you describe. There is no engine braking when this happens so the engine will fall to idle when you let off the throttle and will rev back up to the appropriate RPM to maintain speed in second gear when you step back on it.

Likely you could have driven it on fine by just keeping the speed down....

If the diagnosis is major I would suggest suggesting a swap of the trans shift solenoids instead of a major rebuild and see if that fixes the problem instead of ripping into the trans. The shift solenoids are in the bottom pan and very simple to inspect by dropping the bottom pan. If the shop says it a major trans job then ask them if they have dropped the bottom pan to inspect the shift solenoids. If one has broken off it is very obvious and just about assures that replacing the solenoids (use the service kit with the reinforcement bracket) will solve the problem. If they haven't dropped the pan then ask them to. NO way can anyone tell if the trans shift solenoids are OK without dropping the lower pan. Even if the solenoids look OK I would still have them go ahead and drop the valve body, replace the solenoids and see if the problem is cured before ripping the trans apart. The bottom pan needs to come off to inspect the solenoids anyway and new solenoids would be part of an overhaul so little is wasted by trying this even if it is something more major.

A shift solenoid can crack and disengage from the valve body mount and not set a code so that is not unusual.

A 4T80E is pretty robust and not likely to just loose drive like that. I suspect a shift solenoid.

oldgamer
07-18-05, 12:49 PM
J.A.O.,
I have a transaxle problem very similar to yours (no computer codes) and try to resolve and I posted on a other forum. I didn't drop the pan yet. I hope that it's not a major problem and car has just 70K. I always was told that this transmission is pretty robust and we should change Dexron after 100K and transmission itself will go for hundreds.:rolleyes: Well... I hope that as Bbobinsky said, and he is a really expert, it's just a solenoids (both?). I will try to replace it/them myself, but I'd like to do some research more. What strange is that everytime after restarting of engine transmission works for some minutes again fine, then PD71 shows only gear 2 dosn't matter position of manual shift and car no moves, like in neutral. Does your transmission have same simptoms like mine?

BeelzeBob
07-18-05, 02:19 PM
Must be an epidemic of trans shift solenoids failing......

oldgamer
07-18-05, 02:25 PM
But how come after engine restart it's fine again for some minutes? I explain it to myself that after engine stops, oil pressure drops and because of that solenoids change their position back to normal, but I'm only can guess...:o

BeelzeBob
07-18-05, 03:21 PM
Yea, maybe one of the solenoids is just hanging on by a thread and jumps out of position the first time it tries to apply or something. Drop the bottom pan and check it out. It will need to come down anyway and new shift solenoids are pretty cheap and easy and would be incorporated in an overhaul anyway.....

oldgamer
07-18-05, 03:25 PM
Thank you very much, bbob. I'll drop a pan. The good thing is I'm not using my car much, so I'm not in rush. I should find new seal and filter at first.

BeelzeBob
07-18-05, 03:55 PM
Thank you very much, bbob. I'll drop a pan. The good thing is I'm not using my car much, so I'm not in rush. I should find new seal and filter at first.

No filter...just the metal screens over the pickup so they only require cleaning.

The pan seal is likely reusable. I would drop the pan and see what the solenoids look like. Tug on them to see if they are firmly attached to the valve body as the plastic body of the solenoid is what generally cracks and allows the solenoid to part company from the valve body. If you need the seal then getting it at the same time as the solenoid kit would be easier.

oldgamer
07-18-05, 04:02 PM
If it's possible clean it's even better! Thanks again.

J.A.O.
07-18-05, 08:05 PM
UPDATE!!!

I just got off the phone with the service department. They termed, it a catastophic failure and that the transmission was toast. They have to tear it down to find out what went wrong. My warranty company is also sending out an inspector to check over the car. I was also told that the computer was throwing codes now. I found it odd that it didn't do that for me, but I was hesitant in arguing in that this is something that hopefully the warranty will cover. I was told that if the warranty company sends someone out for a major thing as this, the chances are often good that they may cover it as they have a reason to want to verify the situation, but lack a reason to immediately doubt or disqualify the claim. I have the dealer on my side as they know the car and have been the only ones who have worked on it since I bought it 3 years ago. Not to mention that they (and I) have all the service records confirming that the car has been maintained as instructed. I'm keeping my fingers crossed.

Thanks for all the feedback fellas

BeelzeBob
07-18-05, 10:28 PM
Did you ask them if they pulled the bottom pan and inspected the shift solenoids..???

What symptoms or evidence is there of a catostrophic trans failure..??

If the warranty policy covers it and costs you nothing then I suppose it doesn't matter but it sounds like a solenoid failure may net them a total trans job.....$$$$$$......

J.A.O.
07-18-05, 10:53 PM
Bbob, I hear what you are saying. As far as any key hints of a catastrophic failure, I was told that they took a few codes out. I don't remember what they were, and oddly enough I couldn't get them to come up yesterday when I ran the check. But for all I know, maybe they took it for a test drive and hammered on it and then the codes came out.

I was tempted to ask them about the solenoids, but in order to have a chance of the warranty company covering this, the transmission has to be dismantled so the inspector and the mechanics can take a look at it to determine what happened. I had to roll the dice on this one.

A.) Have them try to replace the solenoids (most likely at my cost) and hope for the best

OR

B.)Take a chance on (and from what I hear is a good chance in the dealer's experiences with these warranty companies) having the inspector see/find that there indeed was a fluke malfuntion that they are bound by contract to repair.

I went with option B as if this goes in my favor, I'll get a new transmission. I have a clean concience as I know the car has been well maintained and the dealer will stand by that as it has been THEY who have done all the work since I bought the car 3 years and 46000 miles ago. It's been a great car and until yesterday, has never let me down. But then again, I've always taken care of it so I really don't think this inspector should find anything but a fluke malfunction. Of course worst case scenario, I suppose I could tell them to try the solenoids after. My gut instinct is telling me to let the inspector look at it. I only hope I'm right.

Thanks for all your help....