areonic1

Alright, so I blew my 700r4 few weeks ago and looking to replace it. I have a twin turbo 350, in an 89 Iroc. I have been spending the last few weeks bashing my mind trying to figure out what to do..So, Im trying to see, what my options are. Like what trannys can be directly bolted on with no mods done, what can be bolted on with little mods, and whats just a pain in the *** to get on.

Ive been thinking, a T56, but it was for all the wrong reasons, I just wanted it, just to have it. Not a very bright idea for 2500bux, when even a really good shifter cant shift faster then an automatic.

So from my understanding, for automatics, theres the 700r4, TH350 and TH400. How much extra does it take to get a 350 or 400 on, which ones better and why. What can be used from the 700r4 stuff.

Any info would be greatfull

84 z28

If i were you i would put in a 4L80e and be done with it.

Ilike2stroke383

t56

you can shift just as fast as an auto unless you suck at life

84 z28

Auto vs standard, auto wins every time. Soon as you touch the clutch by by power to the rear wheels. Dosent matter how fast you can shift there always that instance of no power to the wheels.

areonic1

I watched a thing on TV where they were comparing auto to manual, they had one of the worlds top drivers from the UK, and he couldnt shift faster then an auto. But Im sure your better then all of them.

Also, T56 takes alot of modding, its not just a direct replacement.

Orr89RocZ

iTrader: (20)

Strongest would be TH400. Requires new crossmember for it and possibly torque arm. I dont know if the stock torque arm can bolt to the TH400 tailshaft if you had a mount there. If not, then you will need a torque arm and crossmember kit. I'm running this tranny and use Spohn setup.

I reused my stock shifter and it works ok. Just need to drill a hole in the bracket where the linkage mounts to the pan and mount it to whatever bolt in the pan that lines up with the bracket and takes the slack out of the cable. Its not perfect but it works.
YOu will need to run a vacuum line to the tranny to control shifts and need to wire in a 12 v source to the kickdown sensor thing on the trans to allow it to downshift upon wide open throttle.

I think the TH350 is siimilar. Need a crossmember/torque arm. Wire in the kickdown thing.

How much power are you making? TH400 with decent rebuild can handle 800hp+

4L80E is a strong overdrive unit thats better for cruise but noone makes a crossmember for it and its a big heavy unit that is hard to fit. NOT a bolt in. Electronically controlled so you need a TCI controller to make the thing shift.

These trannies will all need a new torque converter and possibly a flexplate to match. STock style 153 tooth flexplate and starter did not work with my TH400. The converter bolt pattern was different. I had to get the large 168 tooth and because of that, i needed a new starter. Little things that add up.

700r4 can handle decent hp load. I was beating on mine with 500hp and about 600 with nitrous and it held fine. All depends on what kind of driving you do and if you race, how hard you launch.

Ilike2stroke383

my 700r couldnt hold up to my 500 hp and i never even had a chance to be hard on it.. engine isnt even broken in

Orr89RocZ

iTrader: (20)

must have had a bad trans to start with? Mine was built to handle 450-500 but i through more than that through it.

Ilike2stroke383

No you just had a good one i guess, or race built. Any transmission can be good if you dump cash in it. Mine was fresh with a shift kit. Still shouldnt have burned up so fast. Never had the car over 2500rpm. What is that about 220 hp or something my car makes at that rpm? I know it should have handled it. Ive always had bad experiences with the old 700r. Same with my cousin and his 350 s10

GeneralLC

Except in an automatic not all the power is getting to the wheels. There is always some slipping with an automatic.

84 z28

Yes but in a standard soon as you hit the clutch theres "NO" power to the rear wheels.

Ilike2stroke383

then dont use the clutch

Orr89RocZ

iTrader: (20)

Well yeah dont expect a stock piece to hold power. Any tranny in stock form is fairly weak.

shanep1991

i modified my original crossmember to bolt up a TH400 in my 1984 camaro and i used the stock rear, torque arm, torque arm mount and everything, it planted the rear better than stock too and it wasnt even hard to make if you can weld, ill post picks if you want?

built91Z28

I've got a TH-350 in mine. I've also got the Spohn setup to mount it and the torque arm. With the TH-350 you will need a 168 tooth flex plate and a new starter. I bought a Powermaster mini starter that works perfectly.

With the 700 are you sure you had the TV cable adjusted properly? That can make a big difference.

Batass

I had Scott's Transmission build my th350 since hes local and also a sponsor on this site. He put a 9" tailhousing on it and I could use my stock driveshaft until I got a better rear in the car. I told him everything I was doing to the motor and car, and so far it has been holding up very well with 700-775hp. I'm swapping to a t56, I don't care how fast the car is, I care how fast it FEELS.

91interceptorZ

iTrader: (3)

If you're wanting to run a quote unquote, fast manual, run like like a jerico, and shift with no clutch, just slam the next gear (think of pro-mod cars).
But agree, auto is the fastest, 400's are probably the strongest, but don't forget the old powerglide, lol, known lots of guys running those, only two gears though.
Manual tranny choice if you wanna go that route, a tremec tko, or a tranzilla t56, but stick with auto if you're a drag racing person.

jjskibbs

i had a 92 RS with a built 350 putting out 400hp/400 ft-lb and i drove it good, the 700r4 lasted a week and it ate gears... (it had over 100K on it). had it rebuilt and it did it again. had it rebuilt with performance clutches kevlar bands and corvette servo and manual reverse pattern valve body with stahl converter and never had a problem again and it shifted like a ***** effa!