XXLMJ Posted November 3, 2009 Share Posted November 3, 2009 I have a 88 MJ 4.0 auto 2wd. The wrist pins are knocking pretty bad so i have been looking for a motor. I did find a whole XJ a 93 auto 4x4. I do know there is a difference in the HO and renex motor, but would this be a good swap? Or should i keep looking for another motor of the same year. I would like to keep the auto trans, and change the jeep over to 4x4 so i have been looking for complete XJs that are wrecked, but they all have HO motors. Any help or ideas would be great! Thanks Link to comment Share on other sites More sharing options...
Geonovast Posted November 3, 2009 Share Posted November 3, 2009 Sounds like you've got exactly what you need. Get the HO XJ, and swap everything over to your MJ. Easiest way is to completely gut the MJ, move all the wiring, cooling system, vacuum, etc. over from the XJ. Make the MJ look exactly like the XJ did. This includes all the wiring behind the dash. It's a bit of work, but it's worth it. There are plenty of threads and people on here who have done this exact swap. Link to comment Share on other sites More sharing options...
Pete M Posted November 3, 2009 Share Posted November 3, 2009 What he said. :D how much of a project are you looking for? Swapping to HO is a mostly bolt-in procedure, but it is a big undertaking and the truck will be down for a while. Link to comment Share on other sites More sharing options...
XXLMJ Posted November 4, 2009 Author Share Posted November 4, 2009 Well i have another MJ that I'm driving now, old trusty, but very rusty. My 88 that i was talking about it rust free, even under the carpet! The only big problem is winter is coming very quick and my garage isn't very well heated. So i would want to swap everything even the dash, that does sound like a big job. Guess i could start tearing the MJ apart now til i can get my XJ. Link to comment Share on other sites More sharing options...
Automan2164 Posted November 4, 2009 Share Posted November 4, 2009 Its not that bad really, just tedious, since you are swapping EVERYTHING over. The dash, wiring, and all the stuff comes out pretty simple. Rob L. Link to comment Share on other sites More sharing options...
XXLMJ Posted November 4, 2009 Author Share Posted November 4, 2009 Well the XJ i was looking at sold, So is there anything i should be looking for in a good donor? I want to keep the auto, and it needs to be a 4x4. Link to comment Share on other sites More sharing options...
Automan2164 Posted November 4, 2009 Share Posted November 4, 2009 Any XJ/MJ after '90. So, '91-'95 for basic OBD, '96 for later OBD, and '97 up for interior/front clip swap to new style. Rob L. Link to comment Share on other sites More sharing options...
XXLMJ Posted November 4, 2009 Author Share Posted November 4, 2009 Are the Renix motors that bad? I may have found one low miles, and cheap. 4x4, but its a 5speed. Next question is a Manuel swap hard to do? Link to comment Share on other sites More sharing options...
Geonovast Posted November 4, 2009 Share Posted November 4, 2009 Are you really in need for a 4wd swap? Or just the motor. A renix 4.0 in front of a manual will be a direct drop in in front of an auto. All you have to do is put your flexplate on in place of the flywheel, and pop the pilot bearing out of the crank. A manual swap isn't that hard to do, but you'll need a longer rear driveshaft if you do it. Also, what year is the Renix XJ? If it's an 87, 88, or early 89, that transmission isn't worth anything more than a paperweight. Link to comment Share on other sites More sharing options...
XXLMJ Posted November 4, 2009 Author Share Posted November 4, 2009 My motor is bad or going bad, so when i pull it i want to make the truck a 4x4. I'm basically looking for a XJ since they are so common, with a 4.0 and 4x4. I would love to keep a auto trans. but if i have to go with a 5speed i will. All depends on what XJ i find. The one i found is on Ebay and the owner doesn't know what trans. it is other than 5 speed. It is a 90 XJ so hopefully thats a good trans? Link to comment Share on other sites More sharing options...
Geonovast Posted November 4, 2009 Share Posted November 4, 2009 Yup. 90 = AX-15 = awesomeness. Why do you want to keep the auto? Link to comment Share on other sites More sharing options...
Geonovast Posted November 4, 2009 Share Posted November 4, 2009 The problems with getting a 5 speed for your 4wd donor lies in gearing, however. Right now with a 4.0/auto you have 3.55 in the rear axle. 4.0/5 speed has 3.07m which are crap gears. If you get a manual for your donor, you'll either need to find a 3.55 Dana 30(recommended), or set up the XJ rear 3.07 axle for your MJ. Link to comment Share on other sites More sharing options...
XXLMJ Posted November 4, 2009 Author Share Posted November 4, 2009 If gearing is gona be the worst problem, i can always pay to have the dana 35 gears swapped. The rear in my MJ auto is a D44 so I'm not ditching that! So i Think we have come to a conclusion the XJ with the 5speed would be a good way to go Even though its not a HO motor. Oh and i like auto trans manly because I'm lazy. My daily driver is a 5speed MJ. Link to comment Share on other sites More sharing options...
Geonovast Posted November 4, 2009 Share Posted November 4, 2009 Oh, definitely find a 3.55 D30 then. Paying to have gears swapped makes no sense. It'll be 1/100th the price to move perches around. Link to comment Share on other sites More sharing options...
XXLMJ Posted November 4, 2009 Author Share Posted November 4, 2009 Move perches around? What do you mean? I mean i could have a locker put in my front axle, and have the gears changed to what my rear is. Or I'm sure there are plenty D30 with 3.55 gears in the junk yards around hear. Link to comment Share on other sites More sharing options...
Geonovast Posted November 4, 2009 Share Posted November 4, 2009 i can always pay to have the dana 35 gears swapped. Did you mean D30? You can probably find a 3.55 D30 for much less than paying to have the 3.07 one re-geared. Link to comment Share on other sites More sharing options...
XXLMJ Posted November 4, 2009 Author Share Posted November 4, 2009 Ya i meant D30 and throw the D35 at a mailbox or something Your probably right about just finding one at a local junk yard. I'm getting a little ahead of myself i still need to get that donor XJ thanks for all the help. Link to comment Share on other sites More sharing options...
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