th700-r4 transmition, how much power?
 

i have a 700r4 tranny in my 86', it has about 110,000 miles on it. i was wondering how much power can these trans handle and how long would they last? also can they be rebuilt to handle more horsepower if need be?

In stock form I woudn't expect it to take much more than 350 ft/lb of torque, especially with the miles your has.
For "max" power they can be built for...check with Dana here http://www.700r4l60e.com/store/customer/home.php?cat=20

The 86 and mid 87 and up 700r4's have different sprags and lo-roller clutches. The newer units hold more torque. I have put 600 ft lbs of torque thru my nearly stock 87 trans. I do not do this often and realize my trans is the exception rather than the rule. The dana 36 diff is similar. Some break easily and a few others seem to last a long time uner similar high power levels.

There is no definite limit to how much the 700 can handle, it can blow with 300lb-ft any day, and it can last years with 400+ lb-ft put through it.

So it blows up whenever it wants to.

Its not HP you need to build it for, its the torque. If you want to put alot through it, you need a tranny cooler and have both the soft and hard parts upgraded for the torque you expect.

My favorite trans.
The 700R4.
I've blown up 7 (seven) rebuilds.(Done by a "Pro")

On the other hand, I've seen guys put theirs through hell and back and they last a long time.
Go figure.
My "pro" obviously didn't know his arss from a hole-in-the-ground.
Anyway, like Vader said, it will go anytime it wants to.
I personally think they are weak and can't handle gobs of torque.
But then, that's me.
My two cents.

Matt383

what would be a good replacement tranny for the 700r4? i have somewhere near 350 horses and about 430 lbs or torque (estimate on desktop dyno). im still breakin in the engine so ive been nice to it but i want to get a new transmition or rebuild. if anyone knows anything please point me in the right direction. :bigears

Did you check the link in my above post?

Well, the TH400 with Gear Vendors or 4L80 would be the strongest one to run. Likewise a TH350 with additional OD unit installed would work and would eat less power than the 400.

I have seen beefed up 700R's advertised (like, by TCI, etc) rated at 450 hp. I suspect this equals a similar level of torque. This would logically mean a stocker is MUCH less than that level.

I had an 87 Pontiac GTA with about 375 hp and the somewhat beefed up 700R (the tranny guy said that unit in the GTA was not as good as our Vette's) started leaking like the Exxon Valdez after a few trip to the drags. I suspect doing burn-outs are very hard on any stock transmission, not just the 700R :leaving: :smash:

:iagree:

Not meaning to wave the Vader flag today, he just responds quicker I guess.

I have the T-400.
This one is supposed to hold up to 1000+ HP
If you want OD go with the gear vendor set up. ($$$$$)
I just use the 3 speed.
Not on the highway for long periods of time, and I am more of a stop light/drag strip kinda guy.
You need to ask yourself what do you really want to do with this car? and then build accordingly.
More HP = tougher parts, which will stress the other parts,causing need to upgrade those, then you want more HP. It's addicting.

Matt383






"Diapers and politicians need to be changed often and for the same reason."

I currently have a rebuild 700R4 for sale that has all heavy duty parts - and we put 458 HP and about the same torque through it - see the for sale section if your interested (we switched to a manual for road racing)

Carl Johansson

It is simply hit or miss.

I can name several cars with 700's that make INSANE power and they take it just fine.

My old car had two rossler 700's poof at 5000 miles a piece with NO racing at the track and somewhat low abuse(if you want to call it that) street driving.

A friend's Lingenfelter IROC making well in to the 600+ hp range has had tremendous luck with the rossler 700. It had a super ram'd 383 behind it before the 434 and even that took tons of abuse and held up.

It's luck I guess! :cheers:

would the th400 and the th350 bolt right onto my 86' drivetrain or would i have to make any adjustments? oh and what would the $$$ be to rebuild and strengthen my 700r4 now?
thanks for the link bye the way! :thumbs:

Either will require some custom fitting, its not just a bolt-on like headers, you'll probably need custom driveshafts, bellhousing modifications, and custom torque arm. Its been awhile since I researched this subject for my 86, so I'm not sure.

Try running a search on it.

In my area, provided I pulled and reinstalled the unit myself, $1k will buy alot of parts and labor. Normally parts to rebuild(not including torque converter) run under $300. $3-500 is labor and the rest is used for upgrades. I know my answer is vauge but prices vary thruout the country. Upgrade parts are usually debated as well. Some guys swear that you need h/d clutches, I have been using stock paper with great results. Some guys say you NEED a 13 vane pump. I have run 7 and 10 vane units with good luck. I have not personally seen a planetary or input shaft failure below 600 ft lbs. Others say you need these parts for 400 ft lbs. Kevlar bands are neat, never used or needed one. The transgo vs b&m shift kit is usually debated. I have used b&m only with good results so I cannot give an opinion on transgo. The next time someone wants me to install the transgo, I will. I want to see if they are what everyone says the are. The general opinion is that trango is great. Imho, blueprinting the unit is key. Also using the 88 and up sprag and roller clutch is key. Just my long winded $.02

T-400 bolts up to the motor fine.
One issue is the tail shaft housing.
Different yoke & tailshaft length requires different drive shaft length.
Also the 700R4 bolted into the beam for support.
You wont have that with a 400 (or 350)
So you will need to fabricate some support for the trans.
I had a custom tailshaft housing made.
Interior and bolt up face of a 400 with bushings/seals etc. but the external bolt up pattern to fit right where the 700R4 tailshft housing did. Good structural integrity.
I was facing welding in supports for the 400.
So, yeah, it was more $$$ but cleaner IMHO.
Matt383

Check out
http://www.torquedriveinc.com/ for some interesting 700R4 info.