I just installed a Th 400 tranny in one of my buddys trucks and it seems to shift very well. The only problem i encountered, is when you decelerate to a stop and then start going again, it isnt always down to first gear. As soon as you give it gas it slips a little then downshifts and seems to go just fine. It mainly does this when it is cold, it doesnt always do it. Does anyone know what may be the problem? The tranny had been sitting for quite a few years, but it had a new filter and all new fluids before it was put in.

If you have the small adjustable vacuum modulater you can adjust it with a very small flathead screwdriver after taking the vacuum hose off. This may fix it ( B&M makes one at your local parts store)

Could be as simple as a vacuum leak too.

How do you go about adjusting it? It does have the vacuum modulator on the pasenger side front of the tranny.

One more thing... Where exactly should the other end of the vacuum line be hooked on the motor. His truck had a 700 r4 in it before and i changed in the turbo 400. So i just put the vacuum line in to the intake manifold.... is that correct?

Thanks for your help

When i said how do you adjust it i mean.... which way do i turn the screw driver?

It could be the governor springs. I had the same prob in my car, would start off in second. I never did figure it out, smoked the tranny. Try the vacuum, they are cheap, and you can bark the tires in second. :D

Originally posted by Stepside454
How do you go about adjusting it? It does have the vacuum modulator on the pasenger side front of the tranny.

One more thing... Where exactly should the other end of the vacuum line be hooked on the motor. His truck had a 700 r4 in it before and i changed in the turbo 400. So i just put the vacuum line in to the intake manifold.... is that correct?

Thanks for your help

Yea, the vacuum line should be to the manifold - not to the carb.

Turning the screw in clockwise will raise the shift point / compensate for low vacuum. I goes in about 4 turns max from the halfway point then "clicks". Worth a try.

Caveat: Damn few REAL tranny experts in this world... and I'm not one of them.

Well thanks for your help, i really appreciate it! I will definetly give that a try