TH350 Shift Kit Questions

[Pvt_Murphy]

Hey all; I'm new to the concept of shift kits; but the advertized benifits are very appealing. So here are my questions:

1) What exactly does a shift kit do?
2) How hard is the install?
3) What brand is best?
4) Cons?
5) How do i know if my TH350 is locking or not?
6) and what are your presonal experiences with them?

Thanks for your time, Gene.

[MagicRat]

The valve body in your transmission is like a really simple computer. But it uses pressurized hydraulic fluid in place of electricity. It selects the correct gear depending on engine speed, trans output speed and intake manifold vacuum.

The valve body uses precisely calibrated springs inside valves and accumulators (they look a bit like a tiny piston and spring inside a cylunder.

Most shift kits come with several different springs which replace certain specific stock valve body springs. Some also come with a different vacuum modulator and various gaskets. Other kits come with a new 'seperator plate' which is part of the valve body and/or may tell you to drill out the occasional new hole in the stock plate.

These new springs usually increase line pressure (to help prevent slipping) and make the shifts happen faster. Some may allow the engine to rev a bit higher in each gear.

These kits are quite easy to install. You raise the car, remove the trans pan and filter. Then you can remove the valve body. Then just follow the instructions and replace the old parts in the valve body with the new ones. It is VERY important to keep the body CLEAN and follow all instructions exactly.

Once I installed a kit in a Ford C-6 trans. I accidentally reversed the position of a tiny check ball and a tiny spring and completely lost second gear.

Pick the right kit. Not all are the same. Go with a major brand name and you should be okay.
Finally if your trans is worn out or running badly, a shift kit may not help. They are intended for use on a trans that is sound and running well.

[Pvt_Murphy]

cool thanks; I'm thinking after I finish rebuilding this engine I'll rebuild the tranny and toss in a shift kit too.