700r4 vs. 4l80e for 4bt comversion

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Dec 4, 2008
I am in the final planning staged for my 80 series 4bt conversion. The only thing missing is the transmission. I want to keep it automatic and so the decision falls between these two transmissions. Criteria are as follows:

1) grocery getter/family transport
2) car camping
3) no rock crawling, bouldering, etc., seasonal use of fireroads only
4) alternative fuel vehicle, fuel will be turned down, no monster torque
5) no towing

I have talked directly to people that run both with mixed results on both sides. Now to the forum to hear from more individuals that drive these transmissions in their vehicles.

Also in the mix if I go 700r4 I can use an fj60 tcase with a two wheel drive transmission or retain the center locking 80 series diff with a 4wd version. Which would you choose?
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I chose a 4L80 due to the way I was going to use my rig. However, you are not using yours the way I do mine. If you are gentle on it you may get away with the 700R4. I wouldn't recommend it but it may work out for you as long as it's built. The 4l80 has been holding up for me so far and with the new controller (optishift) I can tune it to how I want, I really like it. Either way I'd suggest a custom t.converter. The stock diesel converter is not a low enough stall. I've even had my stock diesel rated t.converter lowered as far as they could go and I still feel it could be lower. I'd probably do a little better on mileage too.
Thanks boots. Your build and thread are pure art. Most lean to the 4l80. It might be wiser for me to spend a little more $ now than a lot more down the road. I was even considering using the t90 that came with it if I could connect to the tcase.
I have the 700R4 stuck to my 4BTA with the early model Toyota split case, has been pretty good so far.

The tranny is built up, a TCC Black Panther. The OD lockout makes it driveable on the highway and split case allows for true RWD. I can run at 60-ish at or below 2K RPMs with decent EGTs. I have DD'd it for a while, done some mild to medium wheeling.

The engine/tranny adapters are out there and you'll need to get a low-stall torque converter as the 4B has such a low power band. TCI makes custom converters, you can get a 800-1000RPM converter. You'll also need an adapter plate for the wave ring as the wave ring has holes drilled for a TH400 torque converter. The PO had the conversion done, and they modified the wave ring by cutting notches in it to work with the 700R4 TC, which eventually failed taking the flex-plate with it. I had Bud Built make me a custom 1/8" adapter ring that worked like a dream, and is rock solid.

Big thing with the 4B is it's loud. When you have everything ripped out, hit up the rear firewall with sound deadening and it would be ebst to pull the interior and sound deaden the floors also.

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