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U-joint failure and carnage

5K views 38 replies 15 participants last post by  9T4YJ 
#1 ·
I bought my YJ on X-mas Eve. It is my first 4X4. I drove it home 250 miles. The only things I noticed unusual was a single hard clank, early in the trip when I was really pushing the 2.5L, trying to get up to speed in the passing gear. There was no more clanking the rest of the way, but I stayed out of passing gear. Also, I felt a lot of sway, when coming off the accelerator or when braking. I attributed that to my inexperience with 33's on a 4" lift. When confirming the sway bar is connected, some off-roading buddies, that I'd shared the experience with, suggested there could be a bad/going bad U-joint.

After having a cold, getting a tag and insurance, replacing some hard top hardware, and fixing my door locks, yesterday, the wife and I were finally ready to get ridin'. We went and filled up the tank. Came home and added some Seafoam. Then, headed for a nearby wildlife drive. I had tried shifting the transfer case, previously, in my driveway, without issue. But, this was to be our first real test of the 4WD.

I checked, in another thread, that it was okay to shift the t-case from 2H to 4H on the fly. So, as soon as I hit the hard-packed dirt/gravel road, going 10-15mph, I pulled it down to 4H. About 75 yards after that the U-joint, between the t-case and front driveshaft, let go. The driveshaft spun freely, denting the tranny pan and bending the shaft, tearing loose the transmission and transfer case linkages, and destroying my E-brake cable. I was able to shift the tranny and t-case to Neutral, from underneath, and get the rig started again. When I did, I found transmission fluid bleeding out around the tranny pan. I'm hoping the impact just killed the gasket and it isn't something more serious. I, also, found that I now have no brakes at all. I hope that is just associated with the E-brake.

I'm not sure how to proceed, now. I don't know if I caused this or if it was just a bad U-joint? Maybe something in the tranny, t-case, or front axel locked up? Should I fix the parts I know are broken and give it another go? Or, should I take it to my local "Jeep specialist" for pro repair/inspection? Part it out?

Anyway, I will try to take some pictures of the carnage, and post them up, today. All help and input is appreciated.
 
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#2 ·
I would take it to someone who can tell if the lift done on your YJ included all the necessary upgrades to the suspension system. When you lift one that much a lot of things come in to play such as driveshaft angles!

Not all is lost until you know what you have and may need to fix it. I always look at it as the cost to repair versus vehicle value. If it cost more to fix than replace, replace.
 
#3 ·
Thanks. That is great advice about cost to repair vs. value.

I know that the t-case has been lowered and it has a SYE.
 
#4 ·
Here is what I'm left with. I held the shaft up to the yoke and the angle seems pretty slight. I haven't found the other bolt for that cap. I wonder if the cap just came loose...






 
#6 ·
I just went and measured. It looks like that's a 1.5" drop kit I've got.
 
#7 ·
I would say that the carnage happened when the vacuum built up enough pressure and finally locked the CAD on the front axle which put you into 4wd.

I guess you found out the hard way that a Wrangler isn't a shift on the fly vehicle?

In 1 of your pics of the E-brake cable, the hard line just above it is wet, this is probably your problem with the brakes. The E-brake cable that was damaged has nothing to do with the brakes working or stopping you.

You need a new driveshaft, there is no fixing that 1. New u-joints, Spicer 1310 is the part numbers. New saddles and bolts to hold the driveshaft on, you can get those from NAPA.

The t-case linkage in the pic doesn't seem to be broken, it just came out. So, put it back in.

I see in the last pick that it has a SYE and an aftermarket rear driveshaft, even looks like a Tom Wood's shaft from the blue on the splines of the slip yoke. So maybe its time to get a new front drive shaft from the same company? I believe they are $189 + shipping.

If the auto trans. is ok, You will probably get out of this little carnage for around $500, that's fairly cheap, for the damage that you have done.
 
#9 ·
I guess you found out the hard way that a Wrangler isn't a shift on the fly vehicle?

In 1 of your pics of the E-brake cable, the hard line just above it is wet, this is probably your problem with the brakes. The E-brake cable that was damaged has nothing to do with the brakes working or stopping you.


If the auto trans. is ok, You will probably get out of this little carnage for around $500, that's fairly cheap, for the damage that you have done.

When everything works, it should shift on the fly without self-destructing

The wet hard brake line may have been leaking before or it took a hit when the cable did. It looks like it is not in the clips that attach it to the frame anymore.

I doubt if the transmission is damaged, probably just needs a gasket and maybe a new pan.
 
#14 ·
Yeah, I commented to my wife, when we couldn't find the other bolt, that isn't strange if such a little thing caused such damage.
 
#18 ·
I don't know what happened, just adding my 2 cents. I shift into/out of 4wd on the fly all the time. No ill effects. Personally I'm guessing your unjoint was bad and came apart, or that bolt came out and let the u joint move around and come apart.
Thanks for the input, bud.
 
#21 ·
To me, it looks like the only impact to the transmission was at the pan and that sprung lever was bent up and the linkage rod was knocked out of it. I bent it back down, but wasn't able to get the rod back in, by hand. You are right, though, it looks awfully wet in that area.

The transmission is not losing fluid, as it sits now, in my driveway. With the motor running it is bleeding fluid from around the gasket. I didn't notice any coming out of the shifter area.
 
#23 ·
When you get ready to put it back together make sure you use locktite on the stap bolts.
Yeah, I'm with ya on that. I was just trying to decide whether to use medium or high strength...
 
#29 ·
Blue Loctite - which is removable is strong enough, if the strap bolts are torqued down properly to begin with

Red Loctite - is permanent! And will likely require heat to remove. Could luck getting those little strap bolts off if you put on red Loctite.

New strap bolts typically come with a blue nylon patch on them already, which is a thread locker.
 
#33 ·
Blue Loctite - which is removable is strong enough, if the strap bolts are torqued down properly to begin with

Red Loctite - is permanent! And will likely require heat to remove. Could luck getting those little strap bolts off if you put on red Loctite.
Nope. Red 222 Loctite is NOT permanent. In fact, I use it daily on small screws. It locks good but is not permanent. The hardware I use it with comes out very easily with 222 but not as easily as if there wasn't any at all. 271 is much stronger and would take some muscle to loosen up but nothing that a little leverage won't take care of. You don't need much either. Just a drop and it'll wick through the threads as it goes in and thin out a lot.
 
#30 ·
I e-mailed the PO about all this. He said he had all the U-joints replaced when the lift was done. I haven't found any thread locker on the recovered saddle bolt. Also, the bolts and saddles look stock, to me. So, I guess they were reused, maybe without thread locker, and possibly no torqued to spec.
 
#36 ·
A normal driveshaft angle max is about 15°. A cv shaft reduces the angle by half. Those are the limits.
 
#38 ·
It is still broken down in my driveway. I've been recovering from an ankle injury for the last month and a half. I have a new Tom Woods driveshaft, new parking brake cable, and new trans filter/gasket. I don't quite have the brake lines figured out, yet. But, I do have a factory service manual. Hopefully, I will be getting to work on my YJ soon.
 
#39 ·
I have the heavy duty "gold" front driveshaft from Tom Wood's. It's probably worth the extra 20 bucks.

The TC drop kit can come off with the SYE. The drop kit is for using a solid shaft and slip yoke. In that application, you want your output shaft and pinion to be on roughly the same angle. In a CV double cardon set up, you want the output shaft level, and the pinion pointing at the output. Your front driveshaft is long enough that the change in angle and lift doesn't have much effect on it.

Your u-joint strap was probably broken already or really loose. The clangs you heard when you first got the Jeep were probably from that joint. When in 2WD, the front shaft does not spin because the CAD (central axle disconnect) keeps the front axle in "neutral". When you shift to 4WD, the TC engages and vacuum is applied to the engage side of the CAD so the front axle is now in "drive".
 
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