My 4L60E started acting up after I did a WOT run up to about 50mph when it shifted into 2nd the tires spun like crazy so I let off the throttle very fast. Ever since then, when I drive from a stop 1st gear is fine, but won't shift into 2nd until about 3k RPM

Once it shifts into 2nd, 2nd gear pretty much has no effect on the movement of the vehicle. If I let it shift into 3rd everything is fine, along with 4th

I took off the pan because it sounds exactly like what a cracked plastic 1-2 accumulator piston would do. But I was wrong, as the piston/seal/housing/springs were in perfect shape. I replaced it anyways with an aluminum piston and put everything back together to still have the same problem.

Another cause of this I read was the servo assembly. What are the chances that it is in the servo assembly? I would have checked it, but I didn't have time to.

THANKS FOR ANY HELP!

 

Time for an 80e swap and your trans issues will be solved for a long time.

 

Try to get a scan tool on your vehicle that has transmission data. Look to see if the command is there well before it shifts. If it is I would suspect that you are in the beginning stages of a band failure. You could try to tighten up the band some to see if you can get a little more life out of it. There are a couple of ways to do this depending on which servos you are using. Vince

 

So you guys don't think there could be a problem in the servo assembly? I mean 4th holds perfectly fine, whereas 2nd is just about completely gone. I ordered a corvette servo assembly (2nd gear apply piston) and will be pulling that apart. I HOPE that is the problem, but I say there is only about a 10% that will be it. I just want to start at the simple things before going straight to a rebuild/4l80e lol

thanks guys

 

I really doubt that the servo or the seals have failed providing it has not been touched in a while. The seals really do not go bad if they are Teflon. The thing here is that you have two servos using the same pin and band right? It has been my experience that not both servos are adjusted equally to the band apply pin. Thus why you have one gear just fine and the other is not there. Also you have less of a load in 4Th so if the band is failing it might not be noticeable. If you are planning on ordering a different second gear servo get a longer pin. This will help tighten up the band some and might help fix this for a while. HTH Vince

 

Good info, I see what you're saying. I'll let you know how the servo assembly looks after i take it out, though now I know the chances are even more extremely slim that it is the problem. It's a free check so I might as well do it!

thanks again

 

My tranny's 2-3 just took a dump with the turbo setup, and worst of all, I never even went WOT,lol.

 

i just went thru this pain...your more than likely burnt ur clutch and the band and drum....well thats what burnt on mine....had the same sympoms as your are describing the scanner wasnt picking it up....get ahold of a transmission guy...you need a rebuild or a 4l80E which is on my list....

 

This man is transmission god. He probably knows correctly. I had the same thing happen to mine under heavy pulls and assume it's the 2-4 band. I fixed it however by installing a 4L80E.

 

well the servo's were all fine, swapped out the 2nd gear servo with the corvette one and I still have the problem. I'm suspecting Vince is 100% correct on his diagnosis. Not worth a rebuild to me though if it will just blow again, so 4L80E it is

thanks guys!