TH350 shifting question
Thread Starter
Racer
Joined: Mar 2005
Posts: 288
Likes: 1
From: Maple Ridge British Columbia
TH350 shifting question
The weather has turned very nice here lately, so I'm finally getting to drive the 1977 coupe I bought last October. The car runs and drives great, but it does seem to shift really hard. For example if I floor it at highway speed (say 50 MPH) it will kick down into second and then will shift back up into third once it gets up to speed. My question is, what should this 2nd to 3rd shift at WOT feel like. In my vette it is very firm and literally bangs into 3rd with an accompanying banging sound. Is this normal? I'm used to modern electronic transmissions, so I just can't remember the good old days when I drove these old auto trannies.
Drifting
Joined: Jun 2005
Posts: 1,523
Likes: 1
From: grand prairie texas
My 77 with a mildly built 350 engine and the turbo 350 transmission with a shift kit at wide open throttle shift between first and second will make the rear wheels momentarly break looks with a chirp of the tires and the second to third shift is very firm and quick but I have no banging sounds on any shifts. You could have a worn motor mount causing the banging sound
Melting Slicks
Joined: Apr 2004
Posts: 2,008
Likes: 38
From: Space Coast Gator Territory
The banging noise could be a bad mount somewhere along the drive line. You are on your own to identify that.
Hard shifts can be softened by going to the modulator valve. On the trans passenger side there is a drum type canister with a hose attached to its back side. Pull the vacuum hose off and with a thin, long flat blade screwdriver, go inside the opening and turn the screw counter clockwise (back it out) half turn at a time and test for effect. Keep track of the turns, so you can return it to the starting point. Be sure to put the vacuum hose back on leak free.
Hard shifts can be softened by going to the modulator valve. On the trans passenger side there is a drum type canister with a hose attached to its back side. Pull the vacuum hose off and with a thin, long flat blade screwdriver, go inside the opening and turn the screw counter clockwise (back it out) half turn at a time and test for effect. Keep track of the turns, so you can return it to the starting point. Be sure to put the vacuum hose back on leak free.
Safety Car
Joined: Oct 2000
Posts: 3,593
Likes: 103
From: Southern Indiana
Your banging you hear could be this bushing: DIFFERENTIAL MOUNT CUSHION - FRONT WITH BOLT KIT
The modulator only affects lower shifting points not wide open throttle.
Only turn it 2 turns in or out and that should be more than you need.
Do not turn it out further than the head of the screw even with the outer tube its in.
The modulator only affects lower shifting points not wide open throttle.
Only turn it 2 turns in or out and that should be more than you need.
Do not turn it out further than the head of the screw even with the outer tube its in.
