Scary JL transfer case failure on hill climb

Unkle_Willy

Unkle_Willy

New member
So today I had my son try driving up a maximum incline obstacle on slick rock at Moab (Hummer Hill). At the steepest part he lost traction and needed to back down to reset his line. While drifting backwards - still in 4-low / Gear M1 - the front tires slid over a crack and then caught again, at which point there was a bang and a nasty gear-grinding noise as the jeep quickly rolled back down the hill until he stopped it with the brakes. When I checked with him the transfer case was still engaged in 4 low, and the transmission still was in M1. It seemed to me like the transfer case popped partially out of gear, but he never touched anything and was able to reset his line and complete the climb. The only driveline mods are an upgraded (lengthened) front driveshaft. Anyone else seen this happen on a JLU Rubi? Going to upload a video when I can.
 
I'm thinking maybe it was not fully engaged into 4 low. I have seen others "pop out" when they are only partially engaged. They will be engaged far enough to move, but added force causes it to go back to neutral, as the teeth are not fully meshed.

It is important to pull firmly into low range, and be sure it is fully engaged.

The pop and grinding follow this thought, as it will still be pulled far enough for the tips of the teeth to gnash against one another.
 
jdofmemi said:
I'm thinking maybe it was not fully engaged into 4 low. I have seen others "pop out" when they are only partially engaged. They will be engaged far enough to move, but added force causes it to go back to neutral, as the teeth are not fully meshed.

It is important to pull firmly into low range, and be sure it is fully engaged.

The pop and grinding follow this thought, as it will still be pulled far enough for the tips of the teeth to gnash against one another.
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Yes, but I should have added that I'd been wheeling in 4 low for a couple of hours before this happened. Nothing changed except this was probably the most strain on the driveline up to that point. When I watch the video it definitely seems like when the front tires slipped backwards over a crack and then bounced down and caught traction is what caused the event. I HAVE had issues sometimes getting the t-case lever to lock firmly into 4-low but as I said - in this case we'd had it locked in for miles of rough going up until this happened.
 
M1 may have been your cause, I tried that on Where Eagles Dare steep climb thinking it would be better but the gearing was so low I could hear the strain and saw the 4LO shifter move, got worried it would jump out of gear that I moved it into D and let it do its thing.
 
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I've also had the T-case pop out of 4L at times. As you found out it can be a real pain in the ass. Ironically, my daughter has wheeled my JL harder than I have, and this has happened to her a few times as well. After numerous times we're
always making sure multiple times that the 4L is engaged fully before an obstacle.
 
Unkle_Willy said:
Yes, but I should have added that I'd been wheeling in 4 low for a couple of hours before this happened. Nothing changed except this was probably the most strain on the driveline up to that point. When I watch the video it definitely seems like when the front tires slipped backwards over a crack and then bounced down and caught traction is what caused the event. I HAVE had issues sometimes getting the t-case lever to lock firmly into 4-low but as I said - in this case we'd had it locked in for miles of rough going up until this happened.
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I've had mine pop out a few times also... Could it be possible that being in reverse it was able to spit it out of gear even though it had already been in 4 low for a while, everything in the TC would be spinning in the opposite direction of normal combined with the shock of the front tires skipping across a crack
 
Talked to a few guys at the Jeep display and they indicated there is an adjustment that can be made in the linkage under the shift console that resolves the pop-out of gear issue.

They said take it to the dealer but maybe some online searching will produce the adjustment procedure.

The Grand Wagoneer is a big ass vehicle lol
 
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Dealer?

I'd appreciate if anyone knows where to find the adjustment procedure that they post it up here. I wouldn't trust the dealers around me with changing a fuse.
 
I thought mine was fine but it kept jumping out of 4lo while on Hotel Rock trail

each time I put it back into 4lo it felt like it was in, but it took pulling into 4lo with some force to get it to stay.
 
CalSgt said:
I've had mine pop out a few times also... Could it be possible that being in reverse it was able to spit it out of gear even though it had already been in 4 low for a while, everything in the TC would be spinning in the opposite direction of normal combined with the shock of the front tires skipping across a crack
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It wasn't in reverse - he was drifting it backwards against the torque converter in first gear. The incline was steep enough that he could do that by letting off the brakes.
 
Unkle_Willy said:
It wasn't in reverse - he was drifting it backwards against the torque converter in first gear. The incline was steep enough that he could do that by letting off the brakes.
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Regardless... the gears in the transfer case were still spinning in the opposite direction from typical. I'm not insisting this was the cause of it popping out like that but the gear selected in the cab of the vehicle doesn't change which direction the tires, driveshaft and gears in the case were going.
 
CalSgt said:
Regardless... the gears in the transfer case were still spinning in the opposite direction from typical. I'm not insisting this was the cause of it popping out like that but the gear selected in the cab of the vehicle doesn't change which direction the tires, driveshaft and gears in the case were going.
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I see your point there. Agreed a possible factor.
 
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