Is it worth rebuilding an older 700R4?

[arveetek]

I'm planning out my diesel swap for my '97 Jeep TJ. I want to go with a 6.2L, 700R4, and NP231. I just happen to have an older 83 model 4WD 700R4. I know that the older models were weaker, but if I did a proper rebuild on this one, would that survive behind a 6.2L in a light-weight non-towing vehicle like a '97 Wrangler?

Casey

[convert2diesel]

If you keep the 6.2 NA, then the 700R4 can be a good tranny. 3/4 is weak but can be made stouter. The torgue lock-up clutch is pitiful but that again is available aftermarket with a better system. Stock these trannys are rated for 350 ft/lbs or about 650 ft/lbs internal. The best of the bunch was 88 or newer as they had all the mods in them, but the earlier ones had a switch for both 3rd and 4th to allow you to wire up the lock-up easily. Careful if you buy a new torgue as the older ones had a different number of splines (can't remember when they changed).

The aftermarket has modified these trannies to take over twice the above figures but the cost is usually prohibitive. If you need these figures, your probably better off finding a good 4L80E or a 400 with a Gear vendor OD.

If the tranny is in good shape, just change the torgue, install the bigger servo (sometimes called the Corvette servo) and install a diesel govenor (otherwise it will shift like crap). The 700 in the Roadmaster has lasted 5 years and 100k (about 10K towing), and it had 150k on it when I did the conversion. Only problem so far is I still haven't figured out how to lock it up automatically. Still use a switch on the dash.

Bill

[arveetek]

I had a 1990 700R4 behind my 6.2L turbo for 14 years. I really liked it.

The 83 700 I have now came from behind a 6.2L. It's just been sitting outside for several years and needs a complete rebuild. I'm just wondering if the 83 model is worth rebuilding or if I should go with a later model like I had in my '81. Money is extremely tight, and I'd rather just use what I have if I could.

Thanks,

Casey

[Robyn]

The early 700R (pre 87) are a sorry lot.
The one you want is the "K" case units or 87-91 (Pre electronic)

These have the dual valve bodies, beefier input shaft and a better case.

The early ones can and do snap input shafts (ask me how I know this)

The late ones, still are only a good starting place. many things need to be done to the inside to get them up to snuff.

I posted a thread some time ago on what needs to be done to a 700R to make it a good tough little player. http://www.thedieselpageforums.com/tdpforum/showthread.php?t=2472821

Read through this entire thread, loads of good info that will help you get a 700R that can stand up to the task at hand.

Robyn

[ToddMeister]

Robyn,

The link above doesn't work, is this the correct post?

http://www.thedieselpageforums.com/tdpforum/showthread.php?t=24728

[Robyn]

Yes thats the thread.

Not sure how I messed the copy and paste thing up but it sure is a dead one

Robyn