th400 problem

NickMaul

NickMaul

Well-Known Member
Joined
Jul 4, 2009
Location
Norfolk, VA
th400 isn't driving like it always has. shifts extremly late (first gear will shift out at 35, second at 50, and it will cruise at third any where after 50) in the book i have it says the solenoid may be shot? and i've gone in and out of 4hi to make sure it was making the proper transfer in the t case. the tranny oil is fine and isnt discolored.
basically it will shift through all gears, except it will shift HARD and extremly late. already replaced the fan clutch and no luck.
keep in mind i have a 4.10 rear end and the engine has to work to make the tranny shift.
im praying its just electrical because i am in no place to be rebuilding.
need help asap
 
no solenoids in a 400 last time i checked.

There is a vacuum modulator that gets engine vacuum, i had a truck that it went bad on and did same thing. Pull the vacuum line off and if there is fluid in there replace it
 
tjrob said:
no solenoids in a 400 last time i checked.

There is a vacuum modulator that gets engine vacuum, i had a truck that it went bad on and did same thing. Pull the vacuum line off and if there is fluid in there replace it
Click to expand...


x2, pull the vacuum line off the vacuum modulator. should be on the pass rear of tranny. common problem to have the diaphram break and fluid get into it.
 
the vacumm line was off. all i needed was a little rubber hose to secure the connection. thank god. thanks for the suggestions
 
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