Hi all. I have been running a built 4l65e behind a supercharged ls1 for about 8 months and had no issues. Just recently i swapped the engine for my blown ls1 stroker and also upgraded from a 3000 to a 4200 stall. Since then we tried to run it up on the dyno and it didnt seem right. I took it to the drags and did 2 passes under power. First one the mph was down a fair bit on what is expected. 2nd pass the mph dropped by 7mph on the first and could smell trans fluid. The car seems to drive ok around town but if you give it a half throttle hit you can smell fluid when you pull up. The engine makes more power than what is recomended.

Is it possible that the convertor isnt locking up? or is it more likely clutch pack or something.

 

I highly doubt it is the converter not locking up. I would venture to guess you have an internal problem in the trans itself.