Interchangeable MJ & XJ parts?

[drase]

I've noticed that XJ's are commonly used as donor vehicles for MJ's, is basically every part from 86-92 XJ's interchangeable with MJ's?

[Geonovast]

As a general rule, 99.95% from the seats forward is the same, given same year, same options. Exhaust after the trans crossmember is different, the rear axles are essentially the same, except for how they mount. Rear springs are completely different, however.

 

Are you looking at something specifically?

[Eagle]

I've noticed that XJ's are commonly used as donor vehicles for MJ's, is basically every part from 86-92 XJ's interchangeable with MJ's?

Aside from what Geonovast posted, you should keep in mind that '86 thru '92 covers basically three "generations" of the XJ and MJ, and other than body parts there isn't a lot of interchange.

 

1986 had the 6-cylinder engine as the 2.8L GM V-6. From 1987 thru 1990 the 6-cylinder engine was the original "Renix" 4.0L I-6. 1991 and 1992 the 6-cylinder engine was the same 4.0L I-6 but it was set up with a Chrysler injection/ignition system that shares nothing with the earlier Renix system. Also, begining in 1991 the speedometer went to electric instead of mechanical, and the polarity of the fuel gauge and sender were reversed.

 

For the 4-cylinder, it was the same from 1986 thru 1990, and in 1991 and 1992 followed the 4.0L and got a new Chrysler injection/ignition system. Again, 1991 and 1992 electronics are not compatible with or interchangeable with the earlier years.

 

They also made some changes to the axles and to the front hubs, knuckles, and calipers. Especially when dealing with the front axle, it is critical to keep all components correct for the year of the vehicle the axle came from or there will be problems. You can bolt in a complete axle from another year, just don't forget what year the "new" axle is when ordering replacement parts for it.

[drase]

Great, thanks guys, I knew I could get the answers I needed here. I'm not looking at any specific year, just waiting for a 6 cylinder, automatic, shortbed to come my way for the right price. I have time to wait, once I get it I'll post it.