Flat Towing

Gotta love that search function!!! Seems this topic comes up about every other week on the 3b page also.

 

When talking about your TJ you're talking apples and oranges compared to an early or intermediate CJ. Your TJ's transfer case has an oil pump driven by the output shaft of the transfer case so the transfer case is oiled when towed as the rear output shaft drives the oil pump so when towing the rear drive shaft in effect is driving the oil pump. The transmission should be in gear or in park as the manual says.

CJ's, any CJ whether it has a Dana 300, Dana 20, or 18 transfer case does not have this pump. When the vehicle is towed with the rear drive shaft in place the rear output of the transfer case is driven by the rear drive shaft, with no oil being pumped to the upper bearings. On 300 and 20 transfer cases with the centered output the oil is not up around the output bearings in general and can starve for oil, causing the bearings to burn out, the shafts to weld themselves together, and generally causing all kinds of issues. On the 18 transfer case the rear output is low down and in the oil so it doesn't have so much of an issue but does create a lot of drag and accelerated wear. On the 18 transfer case the oil being slung around can "drive" the upper gears and the rear output of the transmission causing it to turn. Because the transmission relies on the FRONT input gear to drive the counter gear to splash oil up and lubricate the pilot bearings between the input gear and main shaft as well as the rear output bearings.
By putting the transmission in park or gear it keeps the rear output from turning avoiding this issue.
On the 20 and 300 the friction between the output shaft of the transfer case and output shaft of the transmission can cause the same situation.

This has been covered many, many times here before as said in previous posts.

I've experienced these issues first hands and have had to throw away more customer's transmissions and many transfer cases because of this. Most of them had welded themselves to a point they couldn't be disassembled or had self-destructed to a point there wasn't anything left to salvage. You know it's bad when the bearings weld themselves to the shaft and then the bearings spin in the case wiping that out as well.

 

yow!

i better save up a LOT of money for a truck and a trailer huh?
in about 10 years i will make it to moab......

 

:lurk:

 

heehee

 

Has anyone ever considered posted all the pertinent information about flat towing into a single sticky thread? Something that covers the different models that all the members can refer to?

 

Yeah, that's obviously working out.

 

Nikmil, thanks for the info.i totaly understand the issue with the d20 and 300.i had a 73 cj5 that was trailered .good to know about the pump on the TJ,this is going to be my main hunting/off road rig. The 69 cj5 is going to be a garage/trailer queen so no more flat towing.you bring up some very good points. thanks for your knowledge on the subject.

mike s.

 

No. Just disconnect the rear drive shaft. Problem solved.

 

thanks