Rear Drive Shaft Failure

[calvinhunt]

In a few of my 4-wheeling posts over the past few summers you've seen a red CJ-2A on the trail with me. �Yesterday the owner of that Jeep was in Canyonlands National Park near Moab, Utah. �My wife and I were unable to make the trip with him and his wife because we were out of the area. �My cell phone rang about mid-day showing the red Jeep owner's phone number. �Even before answering I was afraid my friend was in trouble. �He told me that he had twisted his rear drive shaft in two and wondered what he should do. �He was on his way back to his trailer awaiting at the park entrance but had one more "bad spot" to negotiate prior to getting off the trail and couldn't do it in two wheel drive. �Had I been along we would just have temporarily installed my rear drive shaft on his Jeep long enough to get over the bad spot, then put it back on my Jeep so I could get though and we'd be done. �Not being there I suggested he drive the 70 miles back to my home and "borrow" my rear drive shaft (his son from New Hampshire was with him using a rental Jeep-they could have driven that or the owners truck at the park entrance to my place). �I explained how easy it is to remove and install the drive shaft. �Neither he nor his son felt competent enough to tackle that job. The park service told him that he must have the Jeep removed from the park within 24 hours. �He called a AAA towing service from Moab, to come and rescue him. �The towing company charged $200 per hour. �It took 6 hours. �I'm sorry that such an easy fix had to cost him so much. �

I've provided a couple of pics of the drive shaft. �It looks like there had been a crack in the shaft before failure. It is the 1 1/2 inch rusty surface. The rest of it appears to be fresh break. There doesn't appear to be any other damage to the shaft, no gouges, dents, or bends so what would have caused the crack to develop?. �





Have any of you seen this before? �

I see that Kaiser Willys sells NOS front and rear propeller shafts for $199 each (but a local CJ5 owner bought a NOS drive shaft from them and sent it back because it was not really NOS but sloppy and worn with nice paint). Beachwood Canvas sells a new rear shaft for $275 and a new front shaft for $595. �I have an old shaft from surplus parts acquired while doing my restoration project a few years ago, but it seems to have excessive play on the splines (and maybe I should save it as a spare after this experience).

I would appreciate your thoughts and/or experiences on the failed shaft as well as the best way to help my friend acquire a replacement shaft for his Jeeo.

[bretto]

To put it blunt, and no disrespect to your friend but you should be knowledgable to do simple fixes like that before going on such ventures. �And with tools in tote. �Ouch!
If it were mine to fix and the splines were good, I'd take it to a driveline shop and have them re-tube it with the stock ends.

[F Bill]

If it were mine to fix and the splines were good, I'd take it to a driveline shop and have them re-tube it with the stock ends.

x2

Wow.....that was an expensive tow for a minor problem.  I didn't realize driveshafts were getting so expensive...I'm gonna have to put my extras in a safe place now.  Hopefully your bud has learned his lesson about being prepared.... Was he really 6 hours back in the mountains?

I take it the rental jeep couldn't drag his jeep over the tough spot?

I'm not a metallurgist but an existing crack and the type of break would indicate a defect in the tubing since new to me.  It doesn't exhibit any of the deformation you would normally see in an overload situation. I have a feeling he may have had a driveline vibration going on for a while before it broke, too.

[Matto]

Any chance that drive shaft filled with water and froze at some point?

[Bob W]

That is an unusual looking failure. Looks like the metal was very hard with sharp edged fractures. I would think a drive shaft would be softer metal that would tear.

If he is not concerned about originality, some aftermarket driveshafts are stronger. I just purchased a couple from Tom Woods in Ogden UT for $219.00 each. These are heavy duty off road driveshafts that probably won't break behind an L-134.

One problem I see on these old Jeeps that may cause driveshaft problems is U-joint binding. With the rear axle is hanging in the air by the springs, when the Jeep is high centered, the u-joint at the transfer case may bind through it's rotation. This puts incredible forces on all the components, something will fail. This problem is much worse with any lifted suspension.

[Gunslinger]

MY 2 cents, I used to do a lot of metal fatique work, that really looks like a rotational fracture, my guess is that the rusted area is a crack from some time ago, that finally propegated enough to fail the part.  Twisting action and the load from the rear end would cause the failure to rotate around the shaft.  It may have been cracked 25 years ago and finally let go.

Lesson learned, you could have bought a jeep for that towing bill,,, Ouch !!!