I have a 08 2LT with a 2.4l that I threw a supercharger (2.8” pulley) on as well as nitrous and currently my transmission with 185k miles (4t45E)will not accelerate past 3k rpm (anything over 3k rpm is neutral) and no OD, and I have no CEL.

dropped the transmission pan and out came dark dirty brownish red trans fluid and on the magnet I found gray fine metal powder almost grease like texture) bout 3 finger tips covered.

since I don’t really do much work on transmissions was hoping for some input.

thanks in advance.

p.s. for those concerned the car has been driven around the block twice after filter and fluid swap. And now parked on jack stands.

currently contemplating on a remanufactured updated trans but if I can find a fix to hold out for a bit longer that’d be great.

 

Change the shift solenoids and have a look at the fluid tubes above the fluid filter. The solenoids should have a code like P0977 .

 

did you go WOT after the s/c and nitrous were installed? if so how many miles and approx how many times did you get on it?

edit-by the looks of the pic, the trans is toast. your choices is either getting another replacement trans or rebuild this one with updated parts. if it was my trans and have the money, i'd do the latter. i recently had my 170k miles trans go all neutral on me a few months back and i bought it when it had 160k miles. between those mileage, i increased the boost and played around with the trans tune (i honestly think me tweaking the trans tables made the issue worse) was how long my 4t45e lasted. had a reputable local shop rebuilt the trans with updated parts and i believe i found a decent trans tune and never touched them again and it now has about 177k miles so far with my having a lead foot. i'll be changing the fluid/filter here soon when the weather gets warmer.

 

I don't know transmissions.
I think 3000rpm is the rpm limiter, maybe the computer thinks the trans is in neutral.
When I dropped the pan on mine that is about as much sludge I had on the magnet.

 

the forward clutch pressure lines were fine and I have no CEL and did not pull any trans codes with my scanner (snapon) or Hp tuners

 

when my trans went, i had no codes pop up or pending fwiw.

 

With the side cover off the solenoids are easy to replace Note the subframe is dropped several inches

Notice the melting plastic clip on the second solenoid, this was the 2-3 shift solenoid

While you’re at it change the other solenoids Photos courtesy of fastsuv.

 

Of course, what shops usually mean by "rebuild" is just replace the valve body and solenoids