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Discussion Starter · #1 ·
Ive been searching the forums and been reading up on people dropping different auto trans's into their na-t supras. im looking for a trans that will take 400-500 hp on the streets. currently i have a 95 na-t cali spec auto. im keeeping it auto but im basically looking for what parts will i need to upgrade if i were to get either transmission. what would be better for street use. Is there a list anywhere of all the parts i will need to piece together for this swap? can someone point me in the right direction here. i know these th350's and th400's would work but is there anything else i could go with that would take the power im looking for?

thanks
 

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turbo lexus pile
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th400 is the way you want to go. th350 is inferior after a buildup, and a built stock auto will not hold up very well for very long, 2ng gear sprag just cant take the abuse.

ANY built stock yota autos will break after 500 rwhp...especially if you drag race the car or use any kind of slicks. 2nd gear is really weak, and no company does anything to address this weakness. so stay away from those. 6 sp would be the most enjoyable to drive in my opinion. im sure some people have gone from 5 sp to th400...i know people who have gone 6 sp to th400.

the TH400 is really the only option for a good built auto. and it is way cheaper than swapping a 6 speed, however if you are already 5 sp it may be more enjoyable to have the 6 sp.

a built th400 is around $450-650, and the flexplate and adapter plate cost around $1000-1500 for both (check SP racing and ross machine racing). in addition you'll need to cut the drive shaft, make a custom adapter from the shaft to the rear diff, and fab some tranny mounts. when you install it you gotta hammer out you tranny tunnel to fit with some kits. others like SP's are a direct bolt up and no hammering needed, but a little more spendy.

if you switch from your 5 sp to the 6 sp it should cost $2500 for a used tranny or around $4500 for a new one depending if you use v160 or v161. i think youll need a new clutch, new driveshaft, and possibly a new flywheel. (im not sure if the 5sp uses the same flywheel as the 6sp.) and you may also need tranny mounts and a new rear end assy., axles pumpkin etc. to change out to a full 6 sp setup, you dont want to use that stock lsd or non lsd rear.

the th400 saps around 100 rwhp, but actually increases your 1/4 mile times over 6 sp (typically). so a car that puts 650 hp to the wheels through a 6 sp will put down a little over 550 with a th400, however the th400 equipped car will have better 1/4 mile times (depeding on the driver and quality of build). so its really what you want out of the car and how you drive. also you can get gearvendors over drive kits for the th400 for around $2500-4500, that will take it from 3 gears to as many as 6 gears, and you can even pick some of the gear ratios. thats a cool option, takes it form being limited as a drag car to just about any kind of racing you want. thats another prob with the th400...youll run around 3650 rpm just to go 65 mph.

im putting a th400 into my SC300 so ive been researching all this stuff quite a bit and talked to a lot of shops about it. im having a tranny built already, to handle 800rwhp. i havent picked it up yet tho as im kinda lazy, and the car doesnt even run yet. im waiting to get aem and some other mods to do the th400 as well. anyways hope this helps thats all i know about tranny swaps into NAs.
 

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Discussion Starter · #3 ·
yea computer wise what will i need to get so the th400 would be able to run smooth and shift when its suppose to? will i need any engine management to make it work?
 

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A built TH400 is between $450-$650? You smoke too much crack man!

A stock rebuild TH400 is $900 with your tranny. Thats what my guy charges to do a cheapie TH400.

Race trannies are $2,000 with reverse valve bodies.
 

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Grason said:
yea computer wise what will i need to get so the th400 would be able to run smooth and shift when its suppose to? will i need any engine management to make it work?
It is a hydraulic transmission. No computer inputs. Adjust the kickdown linkage and voila, you are done.

4L80E is the electronic version of that and has 4 gears. The case of the 4L80E is larger, but you do get 4 gears. You will need a controller from JET to make it work.
 

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MKV said:
It is a hydraulic transmission. No computer inputs. Adjust the kickdown linkage and voila, you are done.

4L80E is the electronic version of that and has 4 gears. The case of the 4L80E is larger, but you do get 4 gears. You will need a controller from JET to make it work.
just go with a boost logic auto build 2550 shipped they are suppose to hold up very vell
 

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turbo lexus pile
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MKV said:
A built TH400 is between $450-$650? You smoke too much crack man!

A stock rebuild TH400 is $900 with your tranny. Thats what my guy charges to do a cheapie TH400.

Race trannies are $2,000 with reverse valve bodies.

:ugh2:

your guy is ripping you off. i just bought mine complete for $550, including an old tranny and a 800 hp street build up. you should be able to find an old th400 in a wrecking yard for around $200. then have a shop build it up for whatever power you want, and it shouldnt cost two grand or anywhere near that...maybe if you start adding more than the stock three gears with a gearvendors kit...
 

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eblick99 said:
find an old th400 in a wrecking yard for around $200. then have a mopar shop build it up
Funny
 

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turbo lexus pile
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hey thats what i did and its fine. its been in my dads chavelle now for a month or so. once i get all the adapter pieces its going in my lexus. maybe i got mine for cheaper than usual, but from what ive seen the trannys themselves are pretty cheap; even when built up. doing the conversion is what can get costly. RREV motorsports does th400 swaps, they are tuning my SC right now. the owner Tims T6 supra which is making over 600rwhp cost less than $5K for the whole th400 tranny build and swap, and his is a whole hell of a lot nicer than mine.


chevy, mopar, ford, whatever its all the same to me. i dont care much for domestics just the parts i need for my lexus.
 

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turbo lexus pile
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all the kits ive been looking at (my TH400 is still sitting in the garage) come with a hurst type shifter and trans brake...not sure the brand on the trans brake. my TQ converter is a 3200 stall. if i use this tranny in my car, im not going to shift it myself, just put it in drive and go, so i would try to use the stock auto shifter (keep the interior of the car loloking stock, i hate the big chrome trigger shifters in the drag cars). is that what you mean by control?
 

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Discussion Starter · #13 ·
well i picked up a 700r4 so im gona make that puppy work. im rebuilding the entire trans and i have a 3500 stall converter. so hopefully by late summer its ready. im low on money so i gota wait a bit.
 

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Nice White Supra
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Does anyone now how much HP it takes to turn a TH400, TH350 or a tranny of that size? TH400 is like a truck tranny isn't it. Seems like it would take a lot
 

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well i picked up a 700r4 so im gona make that puppy work. im rebuilding the entire trans and i have a 3500 stall converter. so hopefully by late summer its ready. im low on money so i gota wait a bit.
700R4 is no stronger than a toyota trans.
 
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