700R Trans Question

[applebmw]

There a auction coming up that has old corvette motor and trans going to sell, I needing to know what to look at to tell if trans will work behind my 496 BBC in 70 C-10, Anyone ??

[Bigdav160]

I used to build transmission for a living and I would never consider a 700R4 or even a 200-4R behind a Big Block. Oh, I did have one behind a hot 396 in my '67 pickup and it worked.

Pulled it down a year later for a freshening up and it was very worn.

So me, it's 3L80 or 4L80e behind that much torque. The parts in the other lighter duty transmissions are not meant for it.

[applebmw]

Bigdav160, I believe this will be from 99-05 vet, as that's all the guy worked on, maybe earlier, Can you tell me what to look for to identify the transmission? #'s or stampings? Or should I stay away from vet transmission all together?? Thanks for info

[jocko]

Will it "work" as in, will it bolt up and can it be used? Yes.
Will it "work" as in , will it last long? No

I don't recommend a 700R4 behind a 496. If you baby it, it will last for some time, but I'm guessing you're putting the 496 in there for a reason which doesn't include babying it.

4L80E or Allison if you want an overdrive automatic (TH400 if you just want an automatic without overdrive). All of these are very strong transmissions (I wouldn't use a TH350 either behind a BBC, for the same reasons as a 700R4). Being a vet transmission really doesn't mean anything when it comes to sticking it behind a BBC.

Is your 496 a bored older BBC or is it a GM 8.1L from a 2001+ HD? If the latter, they came with 5-spd automatic overdrive Allison transmissions.

[67 chevelle]

keep the 400 thats in it or upgrade to a 4l80 ,,,, 700's and 4l60s suck , and 2004rs take alot of work to get to work correctly , id much rather have a 350 than a 200 , 700 or 4l60

[Bigdav160]

99-05 would be a 4L60e. They used quite a bit of torque management software in the computer to keep them alive.

What you describe is a Corvette rear transmission setup and I don't know what it takes to get it to bolt up to an engine. It's bolted to a torque tube in a Vette

[applebmw]

old bbc 454 punched out to a 496

[jocko]

Copy, thanks. That will be a fun ride. What trans do you currently have? If you’re not going to drive it on the highway a ton, TH400 might be your best, least expensive approach. If you have a lot of highway time planned, then 4L80 might be better. I’d avoid a TH350/700R/200, etc.

[Signkutter]

damn...i bought a 700r4 off Monster transmissions and put it in a 72 C20 6.0 Lq9 swapped truck with 4:10 rear end gearing....supposed to be a more stoutly built tranny according to Monster...bad choice then huh?

[jocko]

Depends on how stout they actually built it. We were kinda talking stock swaps above - but generally speaking, 700R4 not as strong as TH400/4L80E class. If Monster beefed up the usual suspect failures ($) then I wouldn’t worry about it. Also, if you use your truck just for daily driving - ie no hairy burnouts or aggressive off roading, should be ok.

[Bigdav160]

The TH400/4L80e design has no stamped steel gear set members like the TH350/TH700/4L60e/200-R4 do.

That stamped steel sun shell is a design weakness that's pretty common in lighter duty transmissions of all manufactures.

[applebmw]

Originally Posted by jocko

Copy, thanks. That will be a fun ride. What trans do you currently have? If you’re not going to drive it on the highway a ton, TH400 might be your best, least expensive approach. If you have a lot of highway time planned, then 4L80 might be better. I’d avoid a TH350/700R/200, etc.

Has TH350 now, I was hoping for a big score on vet motor and trans.....guess not, I not swapping till needed on trans