TH400 with AWD?

E

E-Rue

New member
hoping someone who has done this in the past can help me out.
getting a race built TH400 for free. :p
just want to know what it takes to make this happen in our trucks.

output?
driveshaft, propshaft?
ECM controlled converter lockup?

e
 
C

CLONE

New member
TurboTony said:
Not sure about the first two, but there is no such thing as a lockup th400 tranny.


Tony
Click to expand...

Not from the factory, but there is aftermarket stuff to convert them as I recall.
 
B

Buster

New member
Re: TH400 with AWD?

E-RUE said:
hoping someone who has done this in the past can help me out.
getting a race built TH400 for free. :p
just want to know what it takes to make this happen in our trucks.

output?
driveshaft, propshaft?
ECM controlled converter lockup?

e
Click to expand...

I talked to Road Master a few years back and he didn't think it'd be a problem, I think he said there is an adapter kit for a few hundred that'll bolt right up. I don't have his number handy, but he was the same guy giving away the tranny at nationals.

Mark L
 
S

smeagol

Active member
I just tuned a Supra powered Lexus that had a turbo 400 with a lockup converter. Dyno'd 864 rwhp, with converter locked up.

You can do it AWD. It's an option I have kept open for the future if the 700 pisses me off enough.
 
ghettosled

ghettosled

SYTY SUPERSTORE
its pretty straight forward especially if it is a manual valve body. Newly located crossmember, new driveshafts, and t-case adaptor. I think Hoover is running one.
 
E

E-Rue

New member
anyone know if this requires a custom converter, im looking but not seeing any lock up converters for a th400.

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K

kbbeckius

New member
I was pondering this the other day, I've built TH-400s before, and other than the 4L80E (based on the TH-400) and the new Allison automatics, this is GM's most bulletproof transmission. It was used in almost all the big block vehicles for more than 20 years. I can just imagine launching a syty with a transbrake!! TCI used to offer some 4wd conversion kits which may work, part #229901 is TH400 to all V8 equipped vehicles w/ 700r4 4x4 trans. According to the old catalog it looks like it comes with an adapter and new output shaft. As for lockup, as far as I know the TH-400 never came with a lockup convertor. There are however some options, the 4L80E uses a lockup, it "MAY" be possible to adapt it to a TH-400, I'm not sure if the spline counts are the same, you would have to check the input shafts and stator splines on the front pump. The easier way, using some "rare" parts is a variable pitch convertor (called switch-pitch) some buick, olds, and cadillac sleds used them in the late 60's (I have a 67' TH-400 so equipped). Some of the Buick big block guys still use them, and there are even some custom stall ones available like 4000rpm high stall, 1800rpm low stall. This was basically an early attempt at improving efficiency, like a lockup. You would need the front pump and input shaft as well as a variable pitch convertor. Another issue you'll have to consider is the difference in gear ratios, a TH-400 has a 2.48 first gear, 700R4 is 3.06. Though the aftermarket has this covered as well, 2.75 and 3.00 low gear sets are available for the TH-400. There are also aftermarket overdrive kits available from gear vendors for the TH-400 although they bolt on the back of the trans and would add extra length, requiring custom driveshafts, relocating the crossmember, etc.. A 4L80E would be better (4 speed W/lockup), but it is very heavy, only has a 2.48 first gear, costs horsepower (extra frictional drag), and requires a computer to run it.

feel free to contact me if you are serious about this endeavor, since I may be looking at this more in the future. :wink:

Thx Brad
 
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