Hey guys, new here.
so I've got a 1987 xj with the aw4 and the 4.0. Its 4x4, it's got 170k. When I bought it the jeep had no interior, no hatch attached, it was rough. I was given a mess of parts from a 95 and a 96 which I installed including hatch seats seat belts the bottom half of the dash trim a set of 32s and a 4" lift. The jeep drove onto a trailer in 4 lo no problem, and after driving it into the garage and installing all the new parts, I drove it out just to have a popping grinding spinning noise, the driveshaft lurching and spinning odd ways. When I shift into gear it'll drive in whatever I put it in, but after driving a short ways itll pop and spin and grind like gears are trying to catch but cant. Itll fall out and then slam back into gear and keep driving, and then pop back out and so forth. I have no idea. The trans fluid is fine, no leaks anywhere either. Also, I've got a little box that was mounted on the bottom trim piece beneath the glove box, should i have a plug on the dash that goes into this or is that box generational? I know the older renix jeeps were different than the mid 90s counterparts. Thanks for the help!

 

Did you install a 4 inch lift?

 

Yes I installed the lift took it out of a parts jeep I had, I used the driveshaft from the parts jeep as well, and that one had no issues driving or shifting

 

Did the lift include a slip yoke eliminator, or some way to correct the pinion angle? A 4 inch lift can affect the angle, and cause driveline issues.

 

No eliminator, but the 96 was identical almost to my 87 and it never did this stock or with the lift, and the 87 did pop out once driving into the garage before it got the lift but I had assumed it was a loose linkage and when I checked The trans linkage was tight

 

The 87s axles sit at a better angle than the 96s as well more turned towards the jeep rather than more parallel so its a pretty clean angle underneath

 

First thought is the xfer case linkage is messed up. Also poor motor and trans mounts can affect the adjustment. Do you perhaps have a 242 full-time xfer case and a front disco axle? That would certainly make the drive shafts spin funny if in fulltime 4wd and the front axle is connecting/disconnecting. The box under the glovebox is probably the transmission computer. If that isn't connected, it won't shift on it's own.

 

I'll check the tcase linkage in the am, its ridiculously covered in mud so that may have something to do with it. Most of the jeep is, and too cold to run the hose for the power washer. I have no idea about the tcase but I'm relatively sure that the renix 4.0s had the 231 case behind them. Is it worth upgrading to the aftermarket linkage? The front axle is vacuum actuated, d44

 

Yeah probably a 231. I assume you don't have a 4wd full option on the shifter

 

I have 2 levers sticking out of the floor, when I said it had no interior I mean it was stripped to bare metal everywhere lol. No shifter pattern, no tcase shifter pattern, no center console until recently, I just mounted a rear view mirror and sun visors. It's got 2 then I pull it up and it clicks and 4x4 pops on the dash then I pull farther and it clicks into low so no no full time option

 

Sure it's the trans popping out of gear and not the transfer case? Sounds like a bit of a cluster in the transfer case shifting department.