Alternator MJ vs XJ.

[512tr]

The alternator stopped charging last week-end, I'm able to get a new XJ alternator.

 

Will a 4.0l XJ (88-90 mod) 100A alternator fit my 87 MJ ?

 

I assume both have built-in voltage regulator?

[87manche]

should. The engine compartment is pretty much the same between xj and MJ.

[square]

Yes It should fit

All the 4.0L are the same in the range 87-90

[CWLONGSHOT]

YUP!!

I have one for mine sittin' in the garage. Just waitin' for warmer weather to drop it in!!

 

Good luck!!

 

CW

[Pete M]

Oooo, not so fast there guys. While the XJ and MJ are essentially the same up there, Jeep used a few different alternators up front, even in the same model year. Only way to know for sure is to check. When I ordered my 170A for my 88, I had to choose between 3 different mounting styles to figure out which would fit in my truck. (If I remember right, mine takes the GM style)

Jeep on!

--Pete

[whowey]

All the 4.0L are the same in the range 87-90

 

 

That's not completely true.

 

In 87, there were some differences. Different mountings for some of the accesory brackets, there are different part numbers for some parts. Variances in vacuum line routings and the like. Remember 87 was the last year of AMC's independence, and the first year of completely new drivetrains in the MJ/XJ. Lots of funky stuff happens, even more than was the 'norm' at AMC.

[CWLONGSHOT]

Well, I'll be!! You learn something new everyday!!!

 

I have four here to look at. My buddies, '88, my two '89's (1 XJ & 1 MJ) and a '90 XJ. They are all the same size shape and mounting. I based my answer on those.

 

Sorry for the miss-information!!

 

CW

[512tr]

Thank for the replies, the alternator is ordered...(should fit XJ 88-90), so I just have to wait and see if it will fit in the existing bracket.