94 YJ U-Joints

[jgermann]

Need a little help with this. I was driving my jeep home the other day and I felt a bad vibration, about 2 minutes later the driveshaft fell out from one of the U-joints going bad. I called autozone and they told me to bring one it to get the right size. Well I did that and I got the 3.219". When I put them on it fit very tight on the yoke side but very very loose in the back. I just want to be sure the I need the 3.219" for the yoke side and the 3.622" on the rear axle side.

Thanks

[Jim_Lou]

Is this the rear driveshaft? Front or rear joint? Is the driveshaft stock? And I don't understand the "very tight on the yoke side but very very loose in the back." Do you mean that the U-joint caps are tight between the ears in the yoke, but smaller in diameter than the eyes in the yoke?

For starters, all four driveshaft joints are the same from the factory. If you have a shaft built up from a collection of pieces, anything is possible.

[jgermann]

Sorry for not being very descriptive. I am replacing both U-joints on the rear driveshaft. The U-joint at the front side of the rear drive shaft fits tight, like the old ones, when both caps are pressed in and the retainting rings are installed. I believe the driveshaft is stock, I am the third owner and there was nothing new put on it from what I can tell. The previous owners used it as a daily drive to commute 120 miles/day. Where you bolt the u-joint to the rear axle, the caps almost fall out from where it seems like its not long(wide) enough to fit correctly. The diameter is fine. When you look at the front there is not slop in the u-joint, and in it is tight and doesn't move from side to side, on the rear you can literally move the u-joint in the caps when it is pressed in and bolted on.

[Pete88YJ]

On a YJ, you'll have caps and screws that hold the ujoint to the axle yoke, rather than ubolts. A lot of times, the yoke can be all washed out for a loose or worn ujoint. Check to make sure the yoke isn't worn -- it could appear that the ujoint isn't fitting properly.

Another option is to drill out the threads on the yoke, and go with a standard ubolt to hold the ujoint in.

check out this link

Jeep Axle U-Bolt Yoke Upgrade

It also seems to say something about differences in 94/95 rear axle ujoint sizes. Give it a read.

Good luck
Pete

[jgermann]

Thanks Pete. The yoke has one small area that is slightly worn, but I don't think it is going to affect it. That site you posted says something about the rear having a different size. It is the 3.622" that goes to the rear axle from the rear driveshaft and a 3.219" that goes from the yoke to the rear driveshaft. Well I guess the guy at Autozone just made me waste 13.99 on the wrong part. I should have known to take both of them with me. I didn't even compare them before I threw one away. I'll try that out in the next couple of days to make sure that is what happened.

Oh yeah, I checked out that u-bolt and I don't think the u-joint is long enough to reach those, it barely fits in the bolt-on clips that are stock on it.

I wonder why they would make them 2 different sizes on the same axle for those 2 years?

[bandhmo2]

Some YJ's used 1310 Joints on both ends of the rear shaft, and some used a 1310 in front and a 1330 in the rear. I have no clue as to why. I really have to wonder what they were smoking when they designed that. I too found out about the different sizes the hard way.

Just for reference:

1310 Joints are 3 7/32" (~3.22") across the caps and use 1 1/16" diameter caps on most rigs, some Fords used 1 1/8" caps.

1330 Joints are 3 5/8" (3.625") across the caps and use 1 1/16" diameter caps on most rigs, some Fords used 1 1/8" caps.

1350 Joints are 3 5/8" (3.625") across the caps and use 1 3/16" diameter caps.

[Jim_Lou]

Different joints on the same shaft from the factory! I'd have bet $40 against that. Thanks for the reminder of how screwed up they were. Probably had a big stock of pinion yokes to use up.

[jgermann]

Thanks for the info. I realized that I screwed up even more than I thought too. I didn't mark the driveshaft on which side went forward so now instead of just change one u-joint this time I have to change the 2 again since I have the thing backwards. Guess thats what I get for getting in a hurry.

[jgermann]

Well by the time I got home last night I had the new u-joint in and it was 10pm, but it went smooth and fit like a glove. I am still chapped about wasting the extra 14-15 dollars on the u-joint that I didn't need but oh well. Since I didn't marked a line to make sure the driveshaft went in the same way as it came out, will I be able ot notice a big difference if it is not in balance anymore?

[Jim_Lou]

Drive shafts don't have to go back a certain way. They're balanced on a machine.