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Th350 vs th400

400 is a heavy transmission, but I prefer it over a th350.

I smoked a pair of 350's fairly quickly, the second of which was a constant pressure (high) unit built in accordance with Jake's recommendations and suggestions.. it spun on a 1-2 shift a little, and when it grabbed, it blew the sprag all over the place.
The clutches were also showing signs of distress at that point, and the trans had a total of about 5 passes and a couple hours of dyno tuning (which is easy in comparison)

the 400 has clearanced clutches a couple of times (one was my fault), but thats been it.
 
Any reason why you don't want to consider the 700r4, 200r4, 4l60e, 80e, etc?

Th400 bone stock will be able to handle pretty much anything you ever throw at it.

A th350 will be cheaper to build, and if you wanted to outfit one for serious drag racing with a nice converter, brake, etc, will more than likely be cheaper to do than a 400. But like Kenny said, they don't like you to be spinning on the 1-2 shift.

a 60e/80e with a shift kit will probably do everything you want to do, but will need a controller; the upside is you can wire up a sloppy transbrake for badass launches without spending all the money on the valve body.

A stock 250k mile 700r4 with a transgo kit, vette servo and run of the mill cooler has held up to 25psi from a t04e plus a small shot of juice pretty regularly. But something with a deep first gear like that might not like a super low geared rear end. Also being the high mileage that it is, it occasionally doesn't like to make the 2-3 shift at WOT and too far into 3rd at WOT will slip. BUT I've also got a 3.08 rear end so I've not needed to run that much rpm in 3rd before its going too fast to feel planted, and I can make a solid pass at the track, turn it 7k and never leave 2nd. Then again, it might be different once I can get a full pass on the bottle.

Thelostartof I believe has run the 200r4 for quite some time, those can be made to hold up pretty easily to a fair amount of power.

Just remember when you're buying a torque converter that converters for these are generally spec'd behind something with twice the cylinders, so they're not going to footbrake for you what they will for others. Unless you help it out with a little bottle feeding that is... My summit 3k stall that footbraked to 3200 behind a 5.7 ls1 only brakes to 2200 behind a redblock before it starts trying to spin tires, but once the launch control shuts off and the solenoids kick on, it loosens up really nicely.
 
MVB or brake for launch-ability, I can get the 4000 (or was it 4500) stall converter in the gold car to stall up to 6k with enough abuse, or only stall to about 3k without said abuse. spec'ing a converter for a 4 banger turbo is a little tough if you're picking up the phone calling most companies, because they're not going to know and odds are you honestly can't tell them everything they'd need to know about it. I would say get a converter for a 350ish hp v8, and add about 500 to 700 rpms to it, and you might be in the ball park.
 
Don't forget about the PowerGlide trans, they will hold over 1000hp.

But you need rear gears to make them work.

I think you want one of the smaller diameter convertors.
 
perhaps OP could regale us with the intended use and power level for the car in question.

in all cases, I'd run the 10inch (or so) converter, not the yuge "stock" gm stuff. the oe 400 converter will ruin your day
 
Hell, my stock 71L with the accum mod has held that power level for a LONG time, including somewhere in the range of 80-100 passes and a dozen of those passes on slicks.
 
I have two aw72s at the house. I did the accumulator mod in them. I'm going onto my 6th transmission. They usually are fine until I take the to the drag strip. I got two larger coolers and a 10" fan on one of them. I know it was mentioned about adding more friction clutches but th400 I probably wouldn't have to worry about the transmission ever failing with what I have.
 
gsellstr said:
Hell, my stock 71L with the accum mod has held that power level for a LONG time, including somewhere in the range of 80-100 passes and a dozen of those passes on slicks.
Click to expand...

What fluid do you run?? I go through a transmission once to twice a year since adding a turbo to my car. Was your transmission rebuilt?
 
do a fresh build on one, get a little looser converter for shenanigans. either dex/merc III (or compatible), or one of the good tractor hydraulic fluids..
 
I got a 3300 stall converter for the aw72L, I'm going to put tractor fluid in my Aw72L transmission going in next. To rebuild one is around 250. I can get th400, converter and required adaptors for around 1000.
 
Nope, mine's a JY pull, grabbed it as a temp unit while my 71 got rebuilt, that's been years back now. This one had 185k on it, fluid smelled like gear oil when I drained it, car had never been maintained. Since then it's had M1 in it, drain/flush every other year or two, that's it, other than the accum mod when I installed it.
 
Nope, the multi-car is about all you can find these days. It's a touch thinner than the Dex3 to meet CAFE standards, but it's labelled as backwards compatible. Didn't like it in the T5, but in the AW it's been doing quite well.
 
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