crpjaviman1

Hey guys,

I have a 1992 K2500 with 4l80e tranny. I recently changed the 1-2 shift, 2-3 shift, TCC and pressure solenoids. My previous problem was that when it shifted, it shifted HARD through all gears.

After installing the first set of solenoids, I noticed that the tranny worked find under 60 mph. I get on a straight away and slowly bring it up past 60 and the fourth gear downshifts to 3rd. I thought it was the solenoids so I changed them 3 times. The last time, I bought the set from a local Chevy dealer but still have the same problem. I can reset the computer and it works under 60. I scanned the ECM and it gives me two codes:


Overdrive faulty or failure (don't remember right now)
QDM fault.

Within these forums I learned the QDM is in the ECM. Can I get this flashed and the problem go away?

If any one can help me shift correctly, I would appreciate it.

Thanks

performabuilt

iTrader: (25)

What code is it giving , In this trans the PCM will not allow fourth if lockup does not occurr or if theres excessive converter clutch slip

crpjaviman1

Since my last post, I changed out the ECM and the speed sensor on the tranny. The previous codes were as follow:
68 - Overdrive fault
8? - QDM fault.

After the ecm and sensor change, I only receive the 68 code. Similar to the previous problem, after changing the sensor, the tranny downshifts now at 65.

I have been told that it is a sticky valve in the valve body. I added Lubegard to the tranny to try to free whatever valve. I read somewhere that there is a screen within the v/b. Could this cause this problem?

Let me know.

crpjaviman

crpjaviman1

Curious thought....my engine revs a little high throughout. For example: when fourth was engaging, my RPMs were 2500 to keep up at 65. I am comparing to my 95 sub which runs 2000 at 70 steady.

Just a thought.

crpjaviman