Home Hey,
New to the forum. I just recently bought my first m37. I looked for a few years before I found on in my area. It sat for 10 years but busted right off with fresh batteries and some fuel in the carb. The transmission is stuck in 2nd gear. The shifter is just moving freely. I need to pull the top cover off to inspect.
Back to my original question - has anyone done a jeep 4 liter conversion on one of these? Would it be easiest to leave transmission and transfer case or replace with engine swap? I've got a fresh 4.0 sitting in the shop an wondering if it's worth the trouble. Any advice would be greatly appreciated.
Thanks,
Quade
Jeep 4.0 repower?
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W_A_Watson_II
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Re: Jeep 4.0 repower?
A couple of us have thought about it and was looking forward to someone doing it. I know the 4.0 I rebuilt (bored and stroked to 4.6L) in my 93 YJ has more power than the basically stock 318 (323 cu in.) in my M37.
If I was to do it' I'd use the Jeep's transmission, either manual or automatic of your choice. And then you have to consider the transfercaae choice. If the transmission is a manual and out of a 2WD Jeep you can keep the M's divorced NP200 TC, other wise I'd go with an aftermarket passenger side drop TC that will mate to your transmission. The real issue here is the the resulting rear drive shaft issue.
With a centered output TC and offset rear axle differential, the drive shaft angle will be unusual, and if it's an off road or low speed on-highway use vehicle, it should work well with proper pinion alignment and CJ drive shaft. If it's on on highway use vehicle, then you have a lot more to consider, like swapping axles as well.
If I was to do it' I'd use the Jeep's transmission, either manual or automatic of your choice. And then you have to consider the transfercaae choice. If the transmission is a manual and out of a 2WD Jeep you can keep the M's divorced NP200 TC, other wise I'd go with an aftermarket passenger side drop TC that will mate to your transmission. The real issue here is the the resulting rear drive shaft issue.
With a centered output TC and offset rear axle differential, the drive shaft angle will be unusual, and if it's an off road or low speed on-highway use vehicle, it should work well with proper pinion alignment and CJ drive shaft. If it's on on highway use vehicle, then you have a lot more to consider, like swapping axles as well.
Last edited by W_A_Watson_II on Tue Feb 10, 2015 2:49 pm, edited 1 time in total.
Re: Jeep 4.0 repower?
I never thought about using a 2WD Trans with the divorced tc. I'll have to take some measurements! The 4.o I have is out of a 2WD jeep mj. This has the potential to be easier then I thought. Thanks for the input Will.
I've had 4 or 5 jeeps with the I6 and most of them had over 250k on the motor and Trans. They are good strong motors with good low end torque. Can't say as much for there new v6.
I've had 4 or 5 jeeps with the I6 and most of them had over 250k on the motor and Trans. They are good strong motors with good low end torque. Can't say as much for there new v6.
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52PLOWERWAGON
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Re: Jeep 4.0 repower?
I would slide the t case back and run duel t cases 
Re: Jeep 4.0 repower?
I think the exhaust is on the wrong side in the 4.0
Rick
Rick
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52PLOWERWAGON
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Re: Jeep 4.0 repower?
it isrickv100 wrote:I think the exhaust is on the wrong side in the 4.0
Rick