How to get true answer on flat towing

See this is the exact confusion I'm talking about. After 60 years, there should be a definitive answer.

 

That's because lots of people post opinions with a very small amount of experience. This is great on a forum like this but can lead to confusion as you found. I just retired from my second job of 22 years building transmissions, transfer cases, and axles for these Jeeps. If you follow what I posted you should have no problems.

 

Nick is right, if you just unlock the front hubs and put the transmission in neutral and such, it will start getting hot in about 30 miles or so. Been there done that. Just unhook the rear driveshaft, that really is the definitive answer!

 

Just not as easy to back up. You can do it for a bit as long as you are going straight back. Yeah, one night in Durango about 11:00 at night. Don't forget about the towbar. A member here spoke of his father out driving his Jeep when the towbar dropped down and dug into the pavement. Bent things up well on the front of the frame. I admit that I did that once in a campground in Utah but was only going about 5 MPH and it picked up the entire front of the Jeep when it dug into the gravel. Now it is bolted and strapped up. To add, I was moving the Jeep to a spot so I could put the rear driveshaft back in and it's tough to get the Jeep off of the towbar if the front wheels are not on the ground.

 

Well I did have to rebuild the transmission :-/ but my father did it that way for years. But if the transfercase is in neutral what turns in the transmission?

 

Nick-Didn't hear you retired. Congrats.

 

Below is from an old thread search on flat towing--referring to a T-90--bet someone will recognize the reply! (Names didn't transfer in the "copy & paste".) Sources say the Borg-Warner T90 transmission was one of the most common transmissions found in 1946 to 1971 Jeeps, and similar in appearance & build to the T-86.
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Comment:
If you flat tow with the rear driveshaft on and the T-case in neutral, I can't imagine the fluid shear from the output gear turning the T-case intermediate gear, turning the mainshaft gear, then turning the transmission mainshaft , and burning up the main bearings and needle bearings in the T-90. Is the fluid level that much lower than the mainshaft gears that it wouldn't splash oil into the bearings? .

Reply:
Sigh. Yes, this can and does happen. Not always but I've had to throw away more transmissions than I care to think about because of exactly this reason. When the output shaft is being driven by the transfer case the speed gears on the main shaft and the pilot/pocket bearings are not being lubricated. These rely on the splash, oil climb, and pumping action of the oil climbing the counter-gear to get the oil up there. When the output shaft is being turned by the transfer case the countergear is held immobile by the input gear/shaft. Hence, the bearings and gears starve for oil. I've seen many where the input and mainshaft were literally welded together. Others where the speed gears were welded to the mainshaft. I had one that had gotten so hot it burned the gear oil out, the counter gear welded to the counter shaft, and the shaft spun in the case. Even the front bearing retainer was ruined on that one. Because the transmission and transfer case share oil with a T-90, the 18 transfer case had a lot of damage in this case also.

Guess next time I get one in I'll have to take pics to show the naysayers what I'm talking about and have proof positive.

 

Interesting

 

Did you read any of the thread before you replied?

 

First off, congratulations on retiring Nick!

Secondly, at the risk of sounding a bit thick... So when you tow with your transfer case in neutral the gears are not in mesh, but the oil acting as viscous fluid, is turning the gears that in turn, turn the output shaft of the transmission. There is no real torque but the turning of the mainshaft with no gear oil riding up the gears coming from the cluster will burn up the bearing surfaces? Gets real hot and friction welds all that together. I never really thought that could happen, but I see how it could now.

Like I said, it might sound a bit thick to ask what has already been stated. I just like to be clear.

That being said, I always listened to the older guys and took off my rear driveshaft if I was flat towing over a couple miles. I did tow that way from Prescott Az to Bellingham WA once like that. No issues and the D41 held up fine.

 

Yes I did ! I was trying to understand, thought that was what this forum was for

 

Can someone make a dash sticker like on CJ Joe's post?

 

So we know the dimensions?

 

One opinion--approximately 4" x 6" would look okay. Readable, yet not too big.

 

I agree on more specific instructions.

As I understand it, short distances (how ever that is defined) do the unlock, tcase neutral and in 3rd gear BUT longer distances or for best peace of mind, do the unlock and rear driveshaft.

I was not aware that you could do locking hubs for rear. I assume this means, no crawling under to mess with driveshaft before you leave then again when you get there plus again when you head back home and again when you get home. That 4 trips under sounds like a pain in the ***. So to me it's either get a trailer for it or add rear locking. Which now brings up what is that approx cost and are there any negative issues with it.

 

Well it does.... in gear. Doesn't' really matter which gear, with the tcase in neutral the engine will hold the gearbox shaft in any gear.

I made it a little smaller than 4x6. Print, laminate, trim, adhere.

 

See this is why after all this time there's still confusion.

Should just delete all these flat towing threads and leave one with correct facts pinned.