TH350 Shifting Problems
Thread Starter
Instructor
Joined: Nov 2007
Posts: 183
Likes: 0
From: Corpus Christi TX
TH350 Shifting Problems
Im new to this transmission so im gonna ask yall what to look for. Ok the problems is forward motion the transmission will not shift inot 2nd or 3rd in the 3 position on the shift column. now if i put it in 1st and shift it manually to 2nd and 3rd it will shift into those gears. So Im askin where do i need to start and what do i need to look for
Drifting
Joined: Oct 2007
Posts: 1,458
Likes: 1
From: Collinsville MS
St. Jude Donor '08
Is the vacuum line from the intake to the modulator valve connected? If it is, then the modulator valve itself may be bad. Its all external and that would be where I would start.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
The vacuum modulator is a can-like gizmo that sticks out of the side of the tranny just above the pan split-line. There should be a steel vacuum line with rubber jumper tubing going to it. If the vacuum signal is not connected to the modulator, or the modulator is damaged/defective, you might have similar shift problems. Your problem could also be a sticky governor assembly (which is at the tail of the tranny under a 4-bolt steel cover).
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Thread Starter
Instructor
Joined: Nov 2007
Posts: 183
Likes: 0
From: Corpus Christi TX
yea well i bought a new part for 10 $ came with a line and i ended up replacing the line and it still doesnt shift i might have to adjust the hard line so it doesnt put as much bend in the hose as it does now but if that doesnt fix it i gotta pull that unit
Drifting
Joined: Aug 2005
Posts: 1,430
Likes: 8
From: Hamilton NJ
Have you checked the other end of the connection where the vacuum line ties into the intake manifold? It is on the top center of the intake right behind the carb and will likely be a shared "tree" connection with other vaccum controlled systems (ie cruise control, ...). That is where my 79 had a problem (the intake tree had cracked). Don't touch that modulator until you first replace the two little pieces of vacuum line (top at intake, bottom at modulator).
