TH400 Shift Kit
You don't really need to buy one. You can drill the 2nd and 3rd gear feed hole and it will give you a nice shift. There are several other things you can do as well. That would be the easiest, and probably most street friendly thing to do.
I'll dig up a separator plate tonight, and take a picture for you to show you exactly what to do. Matter of fact, someone may beat me to it. I know that Jake Shoe on here has a nice thread on another forum about a 400 that goes into great detail.
Use a TransGo Reprogramming kit.
If you are building it from scratch you don't need a packaged kit because there are better ways of doing it, but if you are just installing a kit in an already built transmission there is no better kit than Transgo. It dual feeds the directs and it is the only bolt-in kit that does so. All the rest just make it shift firmer, the TransGo kit makes it capable of handling more torque capacity.
I can tell you to just drill the feed holes, block the 2-3 accumulator, rework the 1-2 shift valve and the accumulator valve, but all you get is firmer shifts not any additional power capacity.
If you are building it from scratch you don't need a packaged kit because there are better ways of doing it, but if you are just installing a kit in an already built transmission there is no better kit than Transgo. It dual feeds the directs and it is the only bolt-in kit that does so. All the rest just make it shift firmer, the TransGo kit makes it capable of handling more torque capacity.
I can tell you to just drill the feed holes, block the 2-3 accumulator, rework the 1-2 shift valve and the accumulator valve, but all you get is firmer shifts not any additional power capacity.
TECH Regular
Joined: Feb 2004
Posts: 439
Likes: 1
From: burbank ca
pg l have posted this before BUT the MOST important thing you can do for your th400 is to have 12 volts to the trans when at full throttle. lf you use a truck trans that mod will suprise you. good luck
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Joined: May 2006
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TECH Regular
Joined: Feb 2004
Posts: 439
Likes: 1
From: burbank ca
p gear what happens when your th400 gets 12 volts is that it now knows that you are at full throttle. acculators (shift shock absorbers) stiffen, the pressure goes up, and the shift points are at higher rpms. lf your trans is in good shape it will make a big differance. the reason l keep talking about truck trans's is because they have the best valve bodies short of L88 corvettes
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