Made A Flat Tow Mistake

Casey.425

New Member
Joined
Jan 24, 2021
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16
Location
Seattle, WA
My transfer case blew up while I was out wheeling at Walker Valley in WA. I'm pretty sure it skipped a tooth due to 4low not fully being engaged. Sounds like a box of marbles with every rotation. I couldn't shift it into anything besides 4low and neutral.

Literally at the same time, my slave cylinder hose cracked and I lost my clutch because I lost all fluid and pressure.


So I had to get flat towed about 25 miles on forest service roads. We went slow, 15-20mph.

I ASSUMED, manual trans in neutral, tcase in neutral. I had no service, I couldn't google it. I see now that is wrong, due to lubrication issues.

Is my NV3550 going to be toast after that short of a distance? It was making zero noise when I coasted it onto the trailer yesterday- no trans bearing noises, so nothing seems to be blown or angry. Thoughts?


I just trailered it home, going to rebuild the Tcase/think about an Atlas.
 
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I think you will be fine. I flat tow behind my motorhome and accidentally knocked the trans out of gear (with t-case in neutral) one day before setting off for about 4 hours at highway speeds. Mine has the super weak AX-5 and while I'm sure I may have added some wear and tear it still works perfectly with no signs of damage.
 
I don't foresee any issues with the transmission. If the transmission did spin, it already had some lubrication from being driven around before, so the bearings were not dry. In addition, at those low speeds, you're unlikely to generate the kind of heat that could cook the oil out of the bearings.

Now if you pulled it cross country at 80 mph we might see an issue.
 
My transfer case blew up while I was out wheeling at Walker Valley in WA. I'm pretty sure it skipped a tooth due to 4low not fully being engaged. Sounds like a box of marbles with every rotation. I couldn't shift it into anything besides 4low and neutral.

Literally at the same time, my slave cylinder hose cracked and I lost my clutch because I lost all fluid and pressure.


So I had to get flat towed about 25 miles on forest service roads. We went slow, 15-20mph.

I ASSUMED, manual trans in neutral, tcase in neutral. I had no service, I couldn't google it. I see now that is wrong, due to lubrication issues.

Is my NV3550 going to be toast after that short of a distance? It was making zero noise when I coasted it onto the trailer yesterday- no trans bearing noises, so nothing seems to be blown or angry. Thoughts?


I just trailered it home, going to rebuild the Tcase/think about an Atlas.
Hi, As a new comer to this great forum I don't understand what is wrong with flat towing a jeep with the transmission in neutral and the transfer case in neutral. Can someone please explain it to me? thank.
 
Hi, As a new comer to this great forum I don't understand what is wrong with flat towing a jeep with the transmission in neutral and the transfer case in neutral. Can someone please explain it to me? thank.
The transfer case in neutral can still apply a small amount of force to the transmission, causing it to freewheel if it is in neutral. However, since the front of the transmission isn't driven, lubricant isn't flowing in the normal paths. Thus, the part of the transmission that is windmilling is not properly lubricated, causing excessive wear and tear on gears and bearings.

It won't blow it up immediately, but it will significantly reduce the life of the transmission. Much like running a power steering pump low on fluid or running a pressure washer dry.

If the jeep absolutely had to be towed with a transmission in neutral, the proper solution would be to pull the driveshafts. In an emergency, you could also flat tow it with the engine idling, but this adds a degree of risk.
 
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The transfer case in neutral can still apply a small amount of force to the transmission, causing it to freewheel if it is in neutral. However, since the front of the transmission isn't driven, lubricant isn't flowing in the normal paths. Thus, the part of the transmission that is windmilling is not properly lubricated, causing excessive wear and tear on gears and bearings.

It won't blow it up immediately, but it will significantly reduce the life of the transmission. Much like running a power steering pump low on fluid or running a pressure washer dry.

If the jeep absolutely had to be towed with a transmission in neutral, the proper solution would be to pull the driveshafts. In an emergency, you could also flat tow it with the engine idling, but this adds a degree of risk.
OK, I understand now, thank you for the very informative explanation.