I just had my transmission rebuilt. Gave the guy my trans and a shift kit (Transgo) from Dana at ProBuilt Automatics. I picked the trans up and put it back in, put 2 gallons + 3 or 4 quarts of fluid. When I Took it out of the garage, reverse works fine, but forward it feels like a manual trans with a slipping clutch.

The trans guy says the shift kit must be causing the issue. Dana at ProBuilt Automatics says the shift kit would have no effect on what's causing the problem and says the guy who built the transmission did something wrong.

What would cause reverse to be fine, but forward act like it's slipping?

 

Is the fluid level right? Did you make sure to adjust the TV cable properly? Is the linkage set right? Converter installed properly? If these are all good then it's internal and the Trans guy needs to go back through it and make it right.

 

I agree. Shift kit would not cause the slippage. Have you looked or smelled the new fluid? Hate to think the clutches are burning up, but I've seen some odd things.
I'd check the pump as well since it sounds like you need to remove the tranny again.
Is this tranny guy a reputable builder? He should back up his work.

 

http://www.tvmadeez.com/

 

I think more info is needed.

1. Can we assume that you haven't driven the car down the road and you've just tried to move it forward in the driveway/garage?

2. Have you tried going forward in any of the other forward ranges (OD, D, 2, 1)?

 

Doesn't sound like the pump, if reverse works right.

Sounds more like something wrong with the forward clutch or the sprag. Sprag installed backwards maybe.

 

I have only backed it out of the garage and down the driveway, then put it OD to move forward. When it felt like it was slipping, I put it in 1 and pulled it back into the garage, still felt like it was slipping. Checked fluid level and smelled it, both OK.

 

Have you contacted the rebuilder? What did they say?

 

this could be any small thing I have seen them not work..from a itty bitty rip in the Vbody gasket. that even a master trany guy missed...lol master what ever....lol

 

I've rebuilt a Hydra-Matic 315, a Ford C4 and a 4L60E over the past 40 years. All three of them worked after I was done. Makes me a legend in my own mind.

Dumb luck

 

I would hound the re-builder to fix it; it's their job. You shouldn't have to diagnose it on here. It's their problem they need to figure out and fix it.

It's obvious to anyone that knows transmissions the shift kit isn't going to cause the issue you describe.