front drive shaft
#1
Member
Thread Starter
Join Date: Dec 2012
Location: N.W. Ohio
Posts: 139
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Grand Cherokee
Engine: 4.0 high output
front drive shaft
Ok haven't posted in awhile frankly because I haven't had any problems. Until now. The u joints in my front drive shaft when to ****. I pulled the drive shaft and replaced the u joints. I repacked the needle bearings in the flange and inspected the pressure spring. I put the new joints in and everything seemed fine. Until I got on the E way. At about 55 to 60mph the front end starts to shake. Just wondering if I need to get it rebalanced or what. It never did that before. I take the shaft out and run with no problems. I have no clue.
#5
Member
Thread Starter
Join Date: Dec 2012
Location: N.W. Ohio
Posts: 139
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Grand Cherokee
Engine: 4.0 high output
Ok so its just a minor adjustment then. I'll pull it back out tomorrow and have a look. Any chance that it might correct itself? Wishfull thinking. I know. Lol
#7
Seasoned Member
Join Date: May 2014
Location: Nor Cal
Posts: 375
Likes: 0
Received 3 Likes
on
3 Posts
Year: 1993 & 1994
Model: Grand Cherokee
Engine: 4.0
when you assembled the double velocity joint did you get all the parts back in time with each other? Did you mark them to make sure they are all back in the same position?
Max
Max
Trending Topics
#8
Member
Thread Starter
Join Date: Dec 2012
Location: N.W. Ohio
Posts: 139
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Grand Cherokee
Engine: 4.0 high output
Yeah I marked all. I just took the shaft back out to have a look. The shaft looks to be inline. One of the cups fell off the forward u joint and I now have 2 broken needle bearings. Been fighting with this Damn thing for 2 months now. About ready to scrap it and start over.
#10
Old fart with a wrench
Okay, here's what happened to me. I've done so many u-joints in my life I figured I knew what I was doing and got complacent.
When I replaced the u-joints on my '97 ZJ's axles shafts, I removed the snap rings and used a BMF hammer to drive out the caps. They were quite rusty and took a lot of force to come out. I actually bent one of the flanges so the new snap ring wouldn't seat in the groove. I had to take it apart again and bend the flange back so that the dimension between the flanges was enough the seat the snap ring. Apparently I got the right flange to bend back because there was no vibration after I got it back together. Don't trash your shaft just yet, it can be saved.
On your front shaft, the u-joints need to be "in phase", that is the joint on the diff needs to be in the same rotational plane as the joint on the t/case. This is controlled by the way you put the spline joint back together. If that's not clear, look at it this way. If you lay the shaft flat on the floor so that the t/case u-joints are parallel with the floor, the front diff joint must be parallel with the floor also.
I built a driveshaft for a hot-rod truck once that needed to be a special length, shorter than original. I set the shaft up on a surface plate with a round bar thru the front joint cap holes resting on blocks of equal height. Then I did the same with the rear flange, rotating it until they were the same angle and dimension. After welding it together and installing it, I figured I'd need to balance it. After running 130 mph in the 1/4 mile, we had no vibration. I guess I did it right.
When I replaced the u-joints on my '97 ZJ's axles shafts, I removed the snap rings and used a BMF hammer to drive out the caps. They were quite rusty and took a lot of force to come out. I actually bent one of the flanges so the new snap ring wouldn't seat in the groove. I had to take it apart again and bend the flange back so that the dimension between the flanges was enough the seat the snap ring. Apparently I got the right flange to bend back because there was no vibration after I got it back together. Don't trash your shaft just yet, it can be saved.
On your front shaft, the u-joints need to be "in phase", that is the joint on the diff needs to be in the same rotational plane as the joint on the t/case. This is controlled by the way you put the spline joint back together. If that's not clear, look at it this way. If you lay the shaft flat on the floor so that the t/case u-joints are parallel with the floor, the front diff joint must be parallel with the floor also.
I built a driveshaft for a hot-rod truck once that needed to be a special length, shorter than original. I set the shaft up on a surface plate with a round bar thru the front joint cap holes resting on blocks of equal height. Then I did the same with the rear flange, rotating it until they were the same angle and dimension. After welding it together and installing it, I figured I'd need to balance it. After running 130 mph in the 1/4 mile, we had no vibration. I guess I did it right.
Last edited by dave1123; 07-08-2014 at 04:01 PM.
#12
Old fart with a wrench
Looking at your picture, the front yoke and rear yoke are 90* out of phase. It's a wonder it didn't come apart! Split the slip joint apart and assemble it so the u-joints are pointing the same way. Then you'll have to replace the burnt out joints in the double-carden. The caps are blue from overheating so the temper is gone.
Last edited by dave1123; 07-09-2014 at 03:37 AM.
#14
Old fart with a wrench
Yeah, that's what I'm talking about. It happens to the best of us. Ask me about the time I was wondering why my truck wouldn't start when I had the distributor rotor in my hand with my tools.