Hey guys and gals. It's been a while since i've last posted. But here is my description before the question. I had my 4l60e built a few months back, from the beginning, it would always want to drop from OD to 3rd with any throttle on the highway. Then i decided to go racing, after that night, 3-4 clutch pack was toast. Within the past few months things have changed. If im below 30mph, the trans will shift to 3rd very slowly and will slip with any throttle. But if i drive it a little harder and delay the shift til after third it holds perfect with zero slip. My question is, what could cause the trans to slip when driving carefully, but hold perfect when being mean to it.

Thanks for the input.
btw... trans is a 4l60e with every sonnax, transgo, beast sunshell, raybestos, and kolene upgrade you can buy. Stock stall, with 3.73 gears and 26" tires.

If anyone can help, i thank you in advance.

 

hmmm..... Line pressure issue, maybe?

 

Exactly right. As you increase the amount of throttle, the PCM commands the PCS (Pressure Control Solenoid, also called Force Motor) to increase the line pressure. Line pressure can vary from about 60 psi to 200 psi, i.e. a lot.

Personally, I would tune the PCM for more line pressure, especially during shifts. I don't know the details, but some mechanics instead turn the "stop screw" on the PCS a quarter turn to increase line pressure at all times.

That might give your trans a bit more life before you need to replace the 3-4 clutch. (I assume that wasn't done yet.) BTW - We can give you good advice on stronger 3-4 clutch combos when you are ready.

 

OOH! I was RIGHT!

 

thanks guys, i will be hopefully soon replacing all the frictions and steels againi will be ordering all my parts from probuilt, the owner was nice enough to spend the good part of an hour helping me. i will try The PCS mod after i r&r the 3-4 pack. Thanks for the input guys.

 

My post #2 in the following thread might help you select the parts for a 7 or 8 friction 3-4 clutch with medium clearance:

https://ls1tech.com/forums/automatic...some-info.html