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Old 01-20-2020, 06:47 PM
Thread Starter
Join Date: Aug 2018
Location: Citrus County, Florida
Posts: 1
Drive train swap

I have a 1990 YJ that needs a lot of TLC
It is lifted with 33's and I wanted to lower it back down to stock.
I was lucky to run across an extraordinary buy on a 1992 YJ that is stock. It had been rear ended and had minor damage. It has a salvage/rebuild-able title. My 1990 is a 4 cylinder with a 5 speed transmission. The 1992 has the inline 6 with 5 speed manual. My intent is to take the entire drive train out of the '92 and put in the '90.Also want to switch out the dash with gauges and possibly the wiring harness. I know I have to change motor mounts but understand the is an inexpensive adapter available for that.
Advice on what I may run into would be appreciated.

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Old 01-20-2020, 07:09 PM   #2
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Location: North Carolina
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I did similar project with an old pickup. 6 cylinder with an auto out and put in an 8 cylinder with a manual. The physical motor/tranny swap went pretty easily. Things to consider are the other interactions between the drive train and frame/body.

Radiator hoses. Are they the same? Are they even on the same side of the motor? Also motor to radiator distance and fan shroud if it has one.
Clutch linkage. Are all the mounting holes there?
Gear ratio. Are the gears in the auto similar as the gear ratio in the manual? If not, how will the new gears interact with the axle gears?
Check all the wiring connections including the computer.
If the final ratio out of the transmission are different, will it effect your speedometer?
Will the driveshafts be the same length?
How will the stick shift and transfer stick pass through the floor? How will you make it look good?

Some food for thought.

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Old 01-20-2020, 08:36 PM   #3
Join Date: Mar 2015
Location: indiana
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Well I 90% complete with the same thing except mine is a 4 cyl. first thing take lots of pictures ( then take some more) next get a note book and a roll of painters tape. anything I disconnected, I marked both sides with tape (wrap tape all the way around and back on itself) label both sides with with the same thing.IE 1w=1w.then I made good notes in my note book. don't leave anything out thinking I can remember where that goes,(you will forget). I used zip lock bags and a marker to label all small stuff bolts screws ect and zip tied them to corresponding parts. Then got lots of help from the big guns here L.M. gottagofast, ect... these guys know a ton and will share (I ask lots of stupid questions and they didn't give up on me) keep every part and screw that you can extras they come in handy. Good luck have fun. P.S Cases of blaster CANO LABS Silikroil the best in my opinion.
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Old 01-20-2020, 09:49 PM   #4
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Join Date: May 2017
Posts: 8,686
No inexpensive adapter... cut 4.0 mounts off donor frame and weld em to your frame OR if the donor frame is good, just swap ur body on to it....
Keep your 4.10 axles if you think you might decide to keep it lifted
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Currently in the stable: ... 97 tj 4.0 5 speed stock....04 tj 4.0 auto 4" and 33's... 98 tj roller for future build... 94 yj sahara 4.5" RE and 33's... 92 yj sbc 3/4 ton axles and 38's... Cj5,7,yj,xj,ex mud dragster project

TJ dash speakers that actually rock! Kicker sub and amp in center console
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Old 01-27-2020, 12:18 AM   #5
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90 YJ,4.2 A/T,A/C,P/S,P/B, 3.07,235/75/15"Nutter, Carter non stepper,2.5"lift and Booms
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Old 01-27-2020, 09:28 AM   #6
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Sell the 90 model to fund repairs on the 92???
87 Wrangler
4 banger
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Old 01-27-2020, 11:06 AM   #7

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Welcome to the Forum flsurveyor#4577,

Good Luck, L.M.
"Wrangler....It's not just a vehicle, It's a lifestyle".
.................................................. ........................
1987 YJ-4.2L-Standard Shift- Re-manufactured Carter Carb-2" body Lift-31X10.5X15 BFG KOs-190K Miles No back seat.
HEI distributor with computer and all related relays and wiring removed.
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Warn front bumper. Matching imitation Warn bumper on the rear.
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Old 02-03-2020, 10:27 PM   #8
Join Date: Dec 2019
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you didn't give much info about the damage, but would it be easier to swap the good sheet metal onto the damaged jeep? Or is the frame damaged as well?

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