Driveline Vibrations and Motor Mount Lifts

[Mike_H]

@bobthetj03 Ha, Ha, my Vibes are gone...How are yours?

Seriously though, I had an extra day of vacation planned before I left on my trip to Drummond Island. I spent the morning on Honey do items, and the afternoon on the jeep. Took some good measurements of the rear drivetrain. When I started...

My Tcase was at 10.1°, my driveshaft was at 14.9°, and my Axle was at 9.1°. That gave me an operating angle of 4.8 at the T-case joint and 5.8 at the rear joint. Its within one degree, so probably OK, but its pushing the limits.

I also wiggled my Axle side U-joint and it had a bunch of play in one direction.

So, what did I do. Well, I didn't like the difference in angle, so I added about a 1/2" of spacer (8 3/8" washers) between the transmission and the transmission mount.

My new drivetrain angles are 9.3° at the T-case, 15.7° on the Shaft, and 9.1° on the Axle...which gives a T-case operating angle of 6.4 and an axle operating angle of 6.6.

I also replaced the U-joint that was bad. Found a broken needle bearing in it!

Went out for a test drive, and everything is Nice and smooth again. If it wasn't such a pain in the ass to put those washers in, I'd pull them and take a drive, just so I know if they make any difference. Thanks for all your input.

 

[bobthetj03]

I too would like to know if it was the axle ujoint, or a combination of that and your angles. This may give me a direction to go with my vibes. Glad you got it sorted brah!

 

[Mike_H]

I too would like to know if it was the axle ujoint, or a combination of that and your angles. This may give me a direction to go with my vibes. Glad you got it sorted brah!

I was thinking about how this might help you...but I don't think it will. I essentially "adjusted" my pinion angle with the stack of washers. You're running a double carden DS correct? I'm just running the single joint variety. If you want, I can take some measurements of my set-up though, and compare them to yours. You are geared lower though, so the DS is spinning faster than mine at any given speed. I just wonder if the type of joints installed in your DS have anything to do with it. The faster the joint spins, the less tolerant it is of misalignment. I wonder if different mfgs have different specs?

 

[bobthetj03]

I was thinking about how this might help you...but I don't think it will. I essentially "adjusted" my pinion angle with the stack of washers. You're running a double carden DS correct? I'm just running the single joint variety. If you want, I can take some measurements of my set-up though, and compare them to yours. You are geared lower though, so the DS is spinning faster than mine at any given speed. I just wonder if the type of joints installed in your DS have anything to do with it. The faster the joint spins, the less tolerant it is of misalignment. I wonder if different mfgs have different specs?

All Spicer non-greaseable ujoints, so don't think it gets much better. I still feel my problem is with the front drive shaft angles, mostly the TC front yoke angle. By doing what you did, basically a small tummy tuck, you lessoned the angle of the front drive shaft at the double cardan joints.

 

[Mike_H]

All Spicer non-greaseable ujoints, so don't think it gets much better. I still feel my problem is with the front drive shaft angles, mostly the TC front yoke angle. By doing what you did, basically a small tummy tuck, you lessoned the angle of the front drive shaft at the double cardan joints.

True. But again, you have adjustable control arms, so it shouldn't matter what your tcase angle is at the front driveshaft, right? Basically you point the axle at the tcase, so there is essentially 0 angle at the axle, and the driveshaft angle is split between the two u joints of the double carden joint. Maybe the angle is too severe and it's binding?

 

[bobthetj03]

True. But again, you have adjustable control arms, so it shouldn't matter what your tcase angle is at the front driveshaft, right? Basically you point the axle at the tcase, so there is essentially 0 angle at the axle, and the driveshaft angle is split between the two u joints of the double carden joint. Maybe the angle is too severe and it's binding?

Something ain't right. I can tell you that.

 

[sweld]

@bobthetj03 Ha, Ha, my Vibes are gone...How are yours?

Seriously though, I had an extra day of vacation planned before I left on my trip to Drummond Island. I spent the morning on Honey do items, and the afternoon on the jeep. Took some good measurements of the rear drivetrain. When I started...

My Tcase was at 10.1°, my driveshaft was at 14.9°, and my Axle was at 9.1°. That gave me an operating angle of 4.8 at the T-case joint and 5.8 at the rear joint. Its within one degree, so probably OK, but its pushing the limits.

I also wiggled my Axle side U-joint and it had a bunch of play in one direction.

So, what did I do. Well, I didn't like the difference in angle, so I added about a 1/2" of spacer (8 3/8" washers) between the transmission and the transmission mount.
View attachment 50592


My new drivetrain angles are 9.3° at the T-case, 15.7° on the Shaft, and 9.1° on the Axle...which gives a T-case operating angle of 6.4 and an axle operating angle of 6.6.

I also replaced the U-joint that was bad. Found a broken needle bearing in it!
View attachment 50593

Went out for a test drive, and everything is Nice and smooth again. If it wasn't such a pain in the ass to put those washers in, I'd pull them and take a drive, just so I know if they make any difference. Thanks for all your input.

That’s a little closer to 1”


Sent from my iPhone using Tapatalk

 

[KCsTJ]

@bobthetj03 Ha, Ha, my Vibes are gone...How are yours?

Seriously though, I had an extra day of vacation planned before I left on my trip to Drummond Island. I spent the morning on Honey do items, and the afternoon on the jeep. Took some good measurements of the rear drivetrain. When I started...

My Tcase was at 10.1°, my driveshaft was at 14.9°, and my Axle was at 9.1°. That gave me an operating angle of 4.8 at the T-case joint and 5.8 at the rear joint. Its within one degree, so probably OK, but its pushing the limits.

I also wiggled my Axle side U-joint and it had a bunch of play in one direction.

So, what did I do. Well, I didn't like the difference in angle, so I added about a 1/2" of spacer (8 3/8" washers) between the transmission and the transmission mount.
View attachment 50592


My new drivetrain angles are 9.3° at the T-case, 15.7° on the Shaft, and 9.1° on the Axle...which gives a T-case operating angle of 6.4 and an axle operating angle of 6.6.

I also replaced the U-joint that was bad. Found a broken needle bearing in it!
View attachment 50593

Went out for a test drive, and everything is Nice and smooth again. If it wasn't such a pain in the ass to put those washers in, I'd pull them and take a drive, just so I know if they make any difference. Thanks for all your input.

I'm going to try this with my rh30 auto.
Did you have to use extra long bolts for the tranny mount with washers?

 

[Mike_H]

I'm going to try this with my rh30 auto.
Did you have to use extra long bolts for the tranny mount with washers?

Yes, hard to go buy some bolts that were a half inch longer. Thankfully they are standard size, so easy to come by.