Thread: Falling out of OD

The on/off reset I agree sounds to be electrical to me. Might look and see if there is some sort of solenoid for the 4th gear cluth that might be getting week.

For our 1997+ transmissions, the 4th gear clutch shaft is what our problem is. On the end there are many splines, and over time of it shifting in and out, the splines wear, and eventually wear completely off. Your transmission still engages 4th, but with no splines, it does not engage, just spins, and sheers off metal into the fluid.

Our fix is a 4th gear clutch shaft, that has hardened splines on the end. Pretty much, same shaft, just heat treated for strength. GM knew this was a problem, and corrected it on a few late model transmissions. But you can buy the shaft and install it your self any time. I did, while i was in there changing my gear set.

~F~

If it happens after the trans is warmed up then you likely have a worn valve body and this is a very common problem with the 4T60E transmissions. If you can get ahold of a scan tool you need to go out for a drive and watch TCC duty % and TCC slippage rpm. If the slippage rpm stays above 100-200 for an extended time and the duty% sits at over roughly 75 during this state the pcm will dissable lockup operation and also block out 4th gear/ OD to keep the trans from running too hot. Cycling the key or clearing the code when this happens will make 4th come back. I have used Transgo 4T60E shift kits for years and they fix the problem hands down, that is IF this is what you have going on but again is very common with your transmission. Get it scanned and see what is going on and you will know what you have to work with.

The shift kit has always cured this problem and I have installed hundreds of these kits. The valve body must be removed to install this kit, there is really nothing you can do with this kit by removing the bottom pan. It includes new accumulator piston pins for the accumulator body and that is it so there isnt much use taking it apart unless you are planning rebuild the whole trans. The kit includes option instructions for a firmer lockup which is not required and I believe they recommend against it unless it is a must-need upgrade.

Has this problem been fixed? Any codes? With my 02 I didn't know that I had a p1811 thats the max adapt long shift code. Untill the car was scanned with a true code reader. You should first get the codes read by a reader that will read the codes. The report back here with what you found. Unless there's a code or not. We can't help you with out more info on the problem the cars doing. But if your planning on keeping the car then just get a full rebuild on the trans. Depending on what you have done with the full rebuild it could run you anywhere from 500 dollars and up. Good Luck