99 Silverado, 5.3, 3.73 gears, performabuilt 4l60e lsx trans. About 2 weeks ago my truck increased line pressure and was hitting so hard between shifts it would bark the tires on the 2-3 shift. I shut it off and let the pressure drop then a week later it kicked the p1870 code for trans slippage. I have researched and everything I have read says I need to change my valve body and TCC selonoid. Does anyone know about this issue. I know sonnax has a rebuild kit but need to make sure it's what I need. Thanks for the help in advance.

 

If you have a built trans i would suggest talking to thrm about it first, but typically yes its a valve body issue, gm even has a bulletin on it fir harsh 1-2 shift and p1870 stored in history... Torque converter could be an issue as well!!

 

So I have talk with Performabuilt. They removed the PWM function in the valve body. Now I have changed the fluid and filter and everything looked good. I still have good shifts but the converter isn't locking up the way it was. Are there any suggestions on testing the converter or do I take the hit and bye another converter? Any suggestions are appreciated.

 

Where did the converter come from, should be under warranty...

 

i had this issue with my performabuilt. i lost my overdrive and drove it that way for a long while then it started to get hung up shifting from 1st to 2nd. I ended up buying a FLT level 7

 

The trans is out of warranty but the converter was shipped with it.

 

Well in that case if the converter came with the trans they are probably both out of warranty then....