Thread: rebuilt trans

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i just had a th400 rebuilt and the reason is it developed a whining noise and after awhile it started laggin in the shifts like a five sec. lag, it was bad but the trans still has this whining noise to it after rebuild. my question is can the torque converter be bad and if it was would it cause a whining noise in it. i have to believe they rebuilt it cause the shifts are awesome better than it has ever been in the time of having this truck

maybe the fluid pump is going out or making the noise. if it is going out you will be rebuilding it again soon. get yourself a tranny temp gauge to monitor you fluids temp, and when it climbs up high its time to shut it down and change the pump, or whatever is whinning. good cheap insurance with a gauge!

ok but if the pump is going out cant they tell something like that and are the pumps rebuildable

THM400 pumps rarely go out. It is very rare. Does the whine happen while in motion or at any time when the thing is in gear? feed us some more info please. There are a few things to dive into that could cause the whine.

the whine is always there even in park but when i am moving and i let of the gas it is real bad

Cavitation and/or case porosity sounds like what is taking place. Pick up tube could be starving, valve body may have loosened, Take it back and have them look at it. The longer this goes on, the more damage will occur.

case porosity isnt that something he would be looking for apon rebuild?

Not always found upon inspection. Not very common but can be exposed after a thourough cleaning at the builders. If it's the case, It was probably working well upon tear down or worked well in it's life. The solutions opened up the pores and bypasses fluid. I only menton it as a probable cause because you are at the point of searching for the cause. Like I said, not too common but has bit me in the past. Other causes are in effect here too. Take it back and have them look at it. Something simple has gone awry and needs to be tended to.