2000xj alternator - compatible with 98?

[blistovmhz]

2000xj alt I believe is dying. I've got a whole whack of 98 alts laying around. 2000 uses a plug connector while 98 had a bolt on. Does anyone know if the voltage regulators are built into both alts? Could I just either swap plug/connectors and expect it to work?

 

[DieselSJ]

Search here and there is a thread on changing the rectifier from one style to the other. Other than the rear connectors, they are identical. However, when you get them apart you may find the brushes are trashed and that is why it is failing.

 

[blistovmhz]

Was just wanting to verify that either both, or neither are regulated by the ECU
Looks like they're identical (as you said) except for the connector and swapping the connector should be simple.

Still not sure it's an alternator problem unfortunately. It was running fine the past few days, but yesterday the voltage gauge intermittently dropped off. Then when the girl went to start it back up to go home, it wouldn't crank over. Had it towed. I looked at it this morning. Wouldn't crank over while boosted to my Jeep, pulled the negative cable at the block and connected it back up. Fired right up. Ran for 5 minutes, then the voltage gauge dropped off again after giving it some RPM, then died. Pull neg cable again and give it a clean and stick it back together, fires up, but every time I give it some throttle, the gauge voltage drops to 12, then 9.
Tapped on the alt cover and voltage came back up. Dunno wtf. I'm sure I didn't touch the alt cover when moving the neg cable around. Suspect they may both be at fault.

 

[DieselSJ]

That is what mine was doing - sort of OK at idle, then volts would drop beyond the bottom of the gauge if I gave it throttle. I put in a 160a from a Durango. The 1998 and 2000 are controlled the same way and are totally compatible. Again, check the brushes when you change the rectifier.

 

[blistovmhz]

Welp, I had a bunch of spare alternators, but someone stripped the brush assembly retaining screws on most of them . Found one with about 25% left on the brushes and stuck it together, and at least thus far, no more wonkiness. I'm starting to wonder if the 2000+ ECU's are just way more sensitive to voltage fluctuations than previous years, cause Jeepy's been throwing tonnes of strange/unrelated/nonsense codes.
After swapping in the new brushes, the motor still did it's low idle thing for the first run, but restarted it and took it for a spin, and seemed to run fine. Fuel economy seems to be tanked though now . I really hate this Jeep. Second most I've spent on an XJ, and by far the worst of the lot. So many little things wrong, plus the blown head and messed up block.
It's slowly coming back together, but I really hate working on stock XJ's.

 

[go1lum]

I have done this swap a few times super easy. Did you have to change the bracket at all? I did this swap last year and had to use the 98 bracket on the 00 because the 98 alt had a clearance issue with the 00 bracket.

 

[blistovmhz]

Naw. Just swapped the brushes cause u couldn't get the connector off all three of my donors.

 

[ehall]

Electrical connector on the back was changed for all Jeep/Dodge/Chrysler in 99