4L60E Shifting Problem?

[Big Greenie]

I have a 1996 K1500 with the 4L60E. The trans does have a stage 2 Transgo shift kit in it. I had the truck parked, outside, for about a week and a half. Prior to this the trans was shifting OK. Over the weekend I took the truck out for a spin and the trans started to act up. 1-2 shift OK, 2-3 shift had a big delay -- felt like it was slipping and didn't want to engage into 3rd. 3-4 shift had a similar delay but not as bad. Yesterday, I took the truck out again and took it to work today. So far, the trans is shifting fine, no delays, no slipping.

Any ideas on what may have happened, is happening? Thanks for the help!

[Big Greenie]

Here's some additional information. Truck has 125K miles, it is lifted 6" w/35" BFG AT's. Trans temps average around 170, never goes above 180ish and if the weather is cool (say mid to high 70's) the temps stay around 160 - 165. Temp readings are taken from my Autometer Pro-Comp trans temp gauge (electric). Thanks again for any help.

[CscottsSS]

sounds like it may be wearing out, my original went out last week on my 96 with 160K on it. That was one of the signs that it was going.

[bolt54]

4L60e transmissions in 1996 model year vehicles have suffered from a PCM problem involving a pin and a wire in the PCM. GM has a TSB on it and a repair kit to address it. As far as I know, it was only a partial year problem before they revised the PCM.

Maybe that is what you are feeling?

[Big Greenie]

Well, got the truck back yesterday from the trans shop. Sat there for a week. The shop owner drove the truck and felt/suspected other things were happening besides the gear shift/delay problem. He was right. He pulled the trans pan and all kinds of debris was found sitting in the pan. He ended pulling the trans and disassembled it. To make a long story short, the sun gear spline ring was completely snapped off and the trans shop couldn't figure out how I didn't lose 2, 4 and reverse gears. Planetary gear drive and bearings, fell apart, literally, as they were pulled out. Most clutches and bands were severely worn. Also, I didn't have the wiring TSB done and if I recall correctly my trans shop told me that the wiring upgrade will prevent the 4th gear band from wearing prematurely. After all the carnage was uncovered, my 4L60E required a complete rebuild and to add insult to injury my rear DS CV joint needed to be rebuilt. But, everything is all back together and shifting/working like a champ.