Unusual performance?

[Roadmaster]

so while i had Irma up on the lift today, i asked him if i could test the 4X4 to see if all 4 wheels engage.
in DRIVE- just the right rear was moving
in 4X4 - just the right rear was moving

i know the 4X4 works because i used it one of the few times we had snowy roads and it performed well.
at least i think it does?

overall the undercarriage looks real good, just need a front axle boot.

[BenM]

It sounds like either you have a 128 (1986) transfer case, or the coupling has gone on the 129. With the coupling has gone bad on a 129 it will act like a 128, just make sure to change the fluid. All four wheels get power, but it doesn't have the limited slip function between the axles.

[Roadmaster]

i thought my '85 had the 129?  i don't really understand what you are telling me since i'm not a mechanic.
what fluid needs changed?  where is the coupling?

[carnuck]

Coupling is inside the tcase. Try stopping the tire by hand. Also, check the round tag on the back of the tcase (in line with the front driveshaft) to see if it says NP128 or NP129.

[Roadmaster]

is that the pumpkin on the rear axle?

[JustinS]

No, the t-case would be attached to the transmission, where the front and rear driveshafts meet.

[carnuck]

Here's a married trans/tcase combo (tcase on the right end) The aluminum piece between the tcase and trans (with the rectangular tab sticking up) is the 1" adapter ring needed to put an AW4 with an Eagle (NP119/128/129) or FSJ (NP208/219/228/229) tcase. NOTE: The AW4 needs to be 23 spline ('91-96 XJ unless you get the whole computer harness wired in from a alter one)



Here's what the tag looks like (This was on the '91 AW4/NP231 I have to go with the Spirit I'm selling)

[Roadmaster]

thank you so much for taking the time to spell it out for me.
next time its up on a lift i'll have them check it out again.
so i hope i am not getting power from just the right rear wheel only.
it drives and performs real nice for me.
its just a sunday driver / back up car anyways,
 but in the event i would need to part with it, i'd like to know what i have

so far my list is just little stuff:
no high beams
no driver side windshield washer
no lighter,
 right turn signal doesn't blink,
no speakers installed,
 and only one wiper speed.
all small tinkering kind of stuff. 
 i want the drive train to work as it should.