Please help. I have a 99 auto with new rebuilt tranny with more clutches, and vacume controlled 4l60e. A sy3500 and 373 gears. On the 1-2 shift it changes fine, but on the 2-3 shift it goes to 5600 and acks like it slips till 6000. Then it shifts. It never touches the rev limiter. On motor it will shift ok but on the spray is where i'm seeing the problem the most. It sometimes will do it on motor too. All of the other shifts are fine. Dose this sound like a pcm problem or is it in the tranny? I have ls1 edit but not shure what to do to fix it. Do you think I might need more line presure? Thanks..

 

Lemme make sure I understand this. You have brand new clutches (what kind?) Your shift point is only 5600 but it slips all the way to 6000 before going into 3rd? Kinda confused because you say it acts like it slips to 6000. Do you have a shift kit? Your PCM still has all of the stock tranny programming (other than shift points), correct? Has the TQ management been removed?

 

I had a tranny manrebuild it for me with stronger and he added more clutches in the upper gears, but not shure what kind. It has a transgo shift kit with their vacume control on it. The tq managment is removed ( I thought that that would solve my problem). I tried changing the rpm in the shift points but didn't help. Everything else is the same as stock. When the car hits 5600, the car falls on it's face till it hits 6000 and then shifts. It's like pushing the clutch in on a m6 till 6000 then letting off. The car then shifts and you can feel the power pick up. I know it is not wise to do this into 4th but the problem dose not happen there either. Thanks..

 

Removing TQ management would make the tranny slip more, not less, as it's the engine is applying full power during shifts. Still, it shouldn't do what you describe.

From what you're telling me, I seriously question the rebuilder's work. No shift kit? No valvebody mods were made?

If he added clutches on your 3-4 clutchpack then you have Alto clutches which are the best there is for you tranny, IMO.

 

So let me get this right, you believe it is in the tranny that is messing up, not something to do with the computer like the mph and rpm points? Thanks

 

If it were just the shift points being off it would shift normally, just not at the right time. That's not what you're descibing when you say "When the car hits 5600, the car falls on it's face till it hits 6000 and then shifts. It's like pushing the clutch in on a m6 till 6000 then letting off."

 

Thanks, I was hoping it might be something easy to fix.