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95 Olds 88 No overdrive


punkrockrob
10-20-2008, 08:50 AM
95 Olds 88. I had the tranny rebuilt last December. When I got it back I noticed that when I start the car and drive the overdrive engages but about a quarter mile it kicks out and won't go back in. I took it back to the horrible shop I used because it was and still is under warranty. Well 4 trannys later, a new computer and prom, crank sensor, torque converter and complete mapping of the electrical system this shop has given up. They cannot find the problem. The error code I get is Torque Converter not engaging properly but it has been changed along with the tranny. PLEASE help me!

maxwedge
10-20-2008, 02:38 PM
There is no way from here to pinpoint the problem, a full scan when road testing the car will confirm whether the pcm is commanding tcc and whether it is applying, also looking at other inputs such as tps and coolant temp readings. Also what is the exact code.

punkrockrob
10-21-2008, 07:52 AM
You may be on to something with the coolant temp. Every now and then the hot light will blink even if the car isn't even warmed up but I was told that this wouldn't affect my trans. There also is a high temp code stored in the computer but the car has never overheated. As far as the exact code goes I will have to get back to you on that. I was only told "torque converter isn't engaging properly". He didn't give me the code. You would think that a well known Transmission shop would check these things but who knows with these guys. What a mistake it was taking it to them! I'll get back to you with the code. Thanks

punkrockrob
10-21-2008, 08:16 AM
Also when the scanner is on for a road test the torque speed is stuck on 240. I was told this number should be constantly moving. When I had the ecm and prom changed at the dealer they said the tcc was working correctly.

Jrs3800
10-27-2008, 01:13 PM
Also when the scanner is on for a road test the torque speed is stuck on 240. I was told this number should be constantly moving. When I had the ecm and prom changed at the dealer they said the tcc was working correctly.

No that number should not be moving all of the time... Most tools will max out on Slip to the tune of 255 rpms or so..

What you should see when the PCM calls for the TC to hit lockup is the TCC Apply precentage go from 0-100% applying the clutch... At this point you should see the Slip RPM's go from 250 or so to almost 0 Rpms of slip... even 10-15 Rpms of slip would be acceptable...

Now this will also depend on what converter was used... This older trans can't use the newer converter with the newer lock up strategy... The newer strategy allows for given amounts of slip... The car you have( same as my 95 Bonneville ) uses the older strategy and its either locked or unlocked...

Its had to explain how the systems function.. On the newer system the PCM can drop into Overdrive at a very low roadspeed....

Not sure what issue you have, but it is a problem and I would recommend having another reputable Trans shop take a look at it... Possibly someone who knows a lot about the GM FWD Transmissions..

punkrockrob
10-28-2008, 08:07 AM
Thank you for the input. These guys have been lying to me from the beginning so taking it somewhere else may be the best option. Thanks again

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