Good morning guys. I just went to back my 1992 AW4 XJ out of the driveway so that my girlfriend could get her car out. I put it in reverse and backed into the street fine, but when I put it into drive and pressed the gas, I went nowhere. RPMs went up but I didn't move at all, it's like I was stuck in neutral. I put it back in reverse and still nothing. I tried this back and forth and went nowhere. Tried to put it in 4WD but that made no difference. At this point I was getting frustrated because cars were lining up waiting for me to move out of the street. Finally, I put it in drive and floored it. It finally caught and I slowly moved forward. Drove it around the block after that and had no issues. Any one have a clue what it could be? Car has 285k on it and I'm assuming original transmission.

Also, this has happened before but not as bad as it did today.

 

Hows the transmission fluid look? did you check level.

 

Here's the fluid level. It's hard to see in the picture so I marked it on the photo with the black line. Looks over full, but this is sitting in the driveway cold, not running.

 

You need to check it with the jeep up to operating temp and running.

With the Jeep running up to temp..Put the Jeep in neutral then check fluid.

 

 

I am having a similar problem, in that my AW4 wont engage reverse once every so often. The truck is new to me, with +200k miles, and I have serviced the trans.

after a few mins of stuffing around, it has so far

It seems no other action is involved in selecting Reverse than the cable moving the valve into position..ie no electric or solenoid operation

Regretably, imo, this means the trans is on its last legs, and I would assume internal pressure is not high enough to engage reverse, which requires the highest pressure.

Note..when it does this, I can detect a faint whirring sound from the trans.

I fitted a reverse light that also beeps, so i can tell for sure the selector is in reverse

next step would be to perform an internal pressure test.

mine fails the "select reverse within 1.5secs" test, outlined in the manual, takes ~1.7secs

 

This makes me wonder if being "over-full" can affect the way the trans works ??.......

 

Right, that's what I was wondering as well. I have read before that being over full can cause slippage, but I know next to nothing about the workings of transmissions.

 

Just an update if anyone finds this thread in the future. Apparently there is a check valve on the transmission lines that stop the fluid from draining out of the torque converter. Also, apparently this doesn't work on my jeep. The solution to this for me has just been to start the jeep and put it in neutral for about 30 seconds to allow the fluid to flow and refill the torque converter. This has "solved" my problem

 

yes, there is apparently a drainback valve, with a weak spring that fails...see youtube on "AW4 stripdown"

My vehicle also does this overnight, takes about 10 secs to pump enough pressure to engage Drive

I think this vehicle had been out of use for at least 2 yrs before I got it, and the trans is quite worn

It now whines in 1st or 2nd, hopefully doesnt get worse