went to the track today and i have a problem with my 1st gear to 2nd gear shift. Trans doesnt slip and 2nd to 3rd is fine. when i shift into 2nd its like the car go's in neutral and hits the limiter. When i let off the gas and get back on it hits 2nd gear and its fine. Sometimes it will go in gear once you let off somethings it might take 2-3 times.

So since it wont slip in gear is the trans ok, what could this be

 

I had the same problem with my old TH400. It would only do it under part throttle. If I hammered down on it, it shifted fine. Maybe someone with some experience with the 400 will chime in.

 

mine seems to only do it at the track at WOT. once its in 2nd gear its fine,

someone help , maybe i'll pull it today since iam going with another stall anyway

what control that 1st to 2nd gear shift, must be it i would think

 

i forgot to add that i just changed the tranny fluild with new ATF ,not sure if it has anything to do with it

also someone said it could be the stock th400 servo?

 

i had to rebuild mine when it did that. between gears it would do a waaaaaaaaaaaa (reviing upward) then after 2 seconds goes into next gear.

 

You either have an issue with the intermediate clutch or the intermediate sprag if I had to guess. Either way the trans will have to come out of the car to be inspected. Vince

 

ok thanks for the help , i guess i'll just drive it real easy to get around and pull it when i get some money

 

does anyone know who makes lighter parts and gears for the th400, the 2.48 kills my 60ft and it would be nice to drop some moving weight in the trans.

 

well i took it for a drive today and in 3rd gear if i floor it and it down shifts the thing just free rev's now so i need to get pulling this thing.

 

Coan or ATI have a bunch of parts for you. Get ready to open up your wallet. These go fast parts are not cheap!

 

Kilgore Superlite

 

forgot to ask what could cause this so i can make sure its fixed, to much power for a stock th400, need a better cooler maybe.

Thinking about pulling it apart and try to find something bad.

 

well how much torque are you making?

 

Only took it to 6300rpm and it was still making a big jump in power, but at 6300 it was 380's rwhp and 320 or 330 TQ . Should be making over 400rwhp at 6800 -7000 tho

whats the stock th400 good for , power that is

 

Stone stock from GM, ~500hp
Good rebuild (assuming 34 element sprag) with stock hard parts ~1000hp

 

The guy i bought it from said it was rebuilt and sat around for a year or more .

Has anyone ever pulled there th400 apart and fixed it or rebuilt it there self. I read its pretty easy if you putting it back the way you found it and not doing mods to it.

 

I rebuilt mine, first timer and will let you know how it worked out in a couple of weeks, I hope.