Angry_bucktooth Posted July 3, 2017 Share Posted July 3, 2017 Okay so I have acquired a donor mj a 1991 4.0 auto 4x4 sb. The frame is completely rotted to $#!& and not worth saving. I have a 1988 2.5 5spd 4x4 Lb. I plan to do a motor/tranny swap since my body and frame on the 88 are mint but it has the small 2.5. The 4.0 with the bad frame fires right up and drives but the frame starts to fold. So I'm looking for as much input as possible since I plan to start the swap in 3 weeks. Here's my plan. Park them side by side and gut my 2.5 completely pull the motor tranny tcase and all the electronics. Then I plan to swing in the 4.0 and tranny bolt it in then attach the tcase and cross member. Next I plan to bring over everything from the 4.0 motor bay and bolt it in leaving just the harness. Once everything is over I plan to bring the harness over and connect it. Now all that should be left is my interior harness and ecu. So I plan to bring over the interior harness and ecu and hooking it up then bring over the 4.0 steering column (column shift) and it should be And I know I have to have my driveshaft rebuilt but is there anything I'm missing or should do differently or tips I feel it should be straight forward and easy since it's a full donor mj Link to comment Share on other sites More sharing options...
Jeep Driver Posted July 3, 2017 Share Posted July 3, 2017 Find someone who needs the 2.5 parts, brackets, pulleys, etc........they have become impossible to source these days. Sounds like you got it, straight forward.....but, of course, nothing is ever straight forward. Fuel system too, rad support, rad. Link to comment Share on other sites More sharing options...
omega_rugal Posted July 3, 2017 Share Posted July 3, 2017 Do anyone know how much 2.5 vs 4.0 Mjs / Xjs were ever made? so far i have only seen 2 4bangers and like a million 4.0s Link to comment Share on other sites More sharing options...
Angry_bucktooth Posted July 3, 2017 Author Share Posted July 3, 2017 @Jeep Driver I know the rad and rad support luckily it's a bolt in swap. But what exactly with the fuel system other then the pump. I know the 4.0 pump puts out more then the 2.5 but that's it. Also @omega_rugal somewhere I saw a list of roughly how many of each model was built even down to the packages Link to comment Share on other sites More sharing options...
omega_rugal Posted July 4, 2017 Share Posted July 4, 2017 i found this MJ Production numbers: 1985: 29,245 1986: 33,386 1987: 43,070 1988: 43,718 1989: 25,311 1990: 9,576 1991: 5,188 1992: 952 XJ Production numbers: 1984 - 93,3261985 - 120,3281986 - 107,2251987 - 139,2951988 - 187,1361989 - 207,2161990 - 151,2301991 - 151,5781992 - 137,8261993 - 144,9611994 - 123,3911995 - 120,2341996 - 286,4631997 - 258,9581998 - 182,8451999 - 186,1162000 - 165,5902001 - 120,454. but nothing about trims or engines... btw, the XJ do outsell the MJ by... a lot Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted July 4, 2017 Share Posted July 4, 2017 Nice list! I tried looking it up once at the only numbers I found were after Chrysler took over Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
Eagle Posted July 4, 2017 Share Posted July 4, 2017 If I were doing it, I would first pull everything out of the good truck, clean and paint the inside of the engine compartment, then swap over the 4.0L wiring harness first. I'd do the engine and drive train last, after the harness is all in place. Link to comment Share on other sites More sharing options...
Angry_bucktooth Posted July 5, 2017 Author Share Posted July 5, 2017 Eagle it's 2 separate harnesses right. And only go threw the fire wall at the bulkhead Link to comment Share on other sites More sharing options...
Jeep Driver Posted July 6, 2017 Share Posted July 6, 2017 OP, I referred your thread to a guy who needs your PS brackets and associated parts. If you are willing to part it out. There are people who need these parts, don't chuck them. Link to comment Share on other sites More sharing options...
mjeff87 Posted July 7, 2017 Share Posted July 7, 2017 If I were doing it, I would first pull everything out of the good truck, clean and paint the inside of the engine compartment, then swap over the 4.0L wiring harness first. I'd do the engine and drive train last, after the harness is all in place. Yes, this. It's MUCH easier to run the harness without the engine in the way. You also need to redo your fuel lines.....the 2.5 ones that attach to your TBI won't work with the fuel rail and return line on the 4.0. The 4.0 lines have QD's on them, but the 2.5's don't. I opted to splice in the 4.0 ends (cut out of a junkyard XJ) into the existing hard lines along the front framerail. Again, much easier to work on without the engine/tranny in the way. Eagle it's 2 separate harnesses right. And only go threw the fire wall at the bulkhead It's one big harness but it can be disconnected into 2 separate pieces on the passenger side at the ignition coil area. The headlight harness is also a separate harness that plugs into the driver side part of the main harness. Link to comment Share on other sites More sharing options...
Angry_bucktooth Posted July 15, 2017 Author Share Posted July 15, 2017 @jeep_driver I'm willing to part and ship prices will be price of shipping and a little extra for me I only gotta make a little to make my money back since I already have parts sold Link to comment Share on other sites More sharing options...
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