Trans swap advice needed

Lobo6

Lobo6

New member
Hey Folks! My '97 TJ's Tf-999 is dying. I have a major powertrain swap set for late 2014, but need to get by with a trans for now.
I am thinking about swapping in a 700-R4 from Advance Adapters. The plan is to keep my 4.0 and the 231 transfer case for this swap.
Has any one done the 700-R4 swap like this and what pitfalls do I need to look for?
The quotes to rebuild my Tf-999 are so close to AA's deal, I lean towards it because I'd have an overdrive gear.
The basics of getting my drive lines adjusted and shifter change are kind of obvious.
My worry is that I heard from one guy (not a very mechanical type dude) that the GM tranny's use a lot of engine torque and make the 4.0 "doggy" in performance.
Thanks, Lobo6
 
I couldn't tell ya, I've read somewhere tho, that the NP231 transfercase shouldn't be used with a transmission that was designed to work with a small/large block chevy V8. But whether or not that info is good I have no idea. I have a spare Muncie 4 speed laying around that I removed from a '79 chevy half ton just in case mine ever dies. But I probably won't use it, the cost of buying the adapters to use the 4.0 and the 231 transfer case with a chevy tranny are more then it would cost me to rebuild my jeep tranny. Just too bad that the NP205 has a passenger side output :/ I have a Small Block 350 (rebuilt), that muncie tranny, and a NP205 taking up space in my garage...lol..
 
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The guys at Advance Adapters didn't see any issue with the strength of the 231 behind a GM trans.
And as far as why the Tf-999 is dying so soon....well this wasn't one of Jeeps best transmissions to begin with. I do run it on the freeway and drive to where I wheel. I think the combination of a lift kit that catches wind, big tires, low gears, a heavy load and mountain passes have taken their toll! There is no overdrive in this transmission.
 
Yeah, I'm rocking a 30RH..the 3 speed auto that the 4 banger got back in 97..its been rebuilt once. I hope it last awhile!
 
On your 3 speed with the 4 cylinder. Just keep everything cool and it should last quite a while. Heat is a real enemy of our auto transmissions. With the crawling I do, I like using a trans cooler with a fan.
 
Lobo6 said:
Hey Folks! My '97 TJ's Tf-999 is dying. I have a major powertrain swap set for late 2014, but need to get by with a trans for now.
I am thinking about swapping in a 700-R4 from Advance Adapters. The plan is to keep my 4.0 and the 231 transfer case for this swap.
Has any one done the 700-R4 swap like this and what pitfalls do I need to look for?
The quotes to rebuild my Tf-999 are so close to AA's deal, I lean towards it because I'd have an overdrive gear.
The basics of getting my drive lines adjusted and shifter change are kind of obvious.
My worry is that I heard from one guy (not a very mechanical type dude) that the GM tranny's use a lot of engine torque and make the 4.0 "doggy" in performance.
Thanks, Lobo6
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I'm new here, not to Jeeps. I have an 05 LJ and lost reverse in my 42RLE, and will NOT put money into what I consider a junk transmission. The 700R4 swap really is the best route and it's the route I am going. I think you will be quite happy with it.

One of the guys I wheel with from the Lone Star Jeep Club has had this swap done on his, and it is nice. One thing to consider is you have to swap the ECU from an auto one to a manual one to keep from getting codes.

These trans have a great first and overdrive gear and can be built for a variety of horsepower/torque numbers. They will not rob the torque the 4.0 has as long as you match your torque converter, ie: low stall.

The 231 will hold up quite well behind the 700R4, unless you stroke your motor and push your horsepower/torque through the 300 range. Another and maybe cheaper option would be to find a good AW4 from from an XJ and swap in.

Stu Olson has an excellent write up on the AW4 swap into an older TJ here: http://stu-offroad.com/engine/aw-4/aw-4-1.htm

Hope this help you make your decision.
 
I agree, the 700R4 should be a great swap. Further more, if you swap in a Vortec or LS motor later on you already have a trans for it that will bolt right up.
 
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