Another Mystery Vibration Only Under Load

[TX-ZACH]

Happy Labor Day guys and gals. The Mrs and I were out for a dinner cruise and had a vibration start at about 40mph and up. Let of the throttle and all smooth and starts to vibrate again if throttle is applied. It has a rhythm to it but seems not to get much worse with higher speeds. RPM seems not to matter. I did a visual inspection when we got home but could not detect anything out of place.

This morning I am going to grease all the zerts in shafts to see if they take a little more. Roll it in neutral while yanking on drain train. Check for loose bolts. Last time I checked them was about 3000 miles ago. I read some other threads about angle and balance the the shaft and torque the CV. Can anyone tell me other things to look at?

*5.5" Lift w/ 35" tires
*New motor about 10k miles ago
*Drivetrain has never been apart since Ive had it

 

[TX-ZACH]

I beleive I have found the culprit. Looks like a bad ujoint, one with a missing grommet or damaged, 1st one at the CV going to the Transfer Case. Pic 1 with bad, Pic 2 with good, Pic 3 with both together.

 

[Yeller]

That’ll do it.

 

[TX-ZACH]

Double checking to be sure I am ordering the right parts to rebuild this drive shaft. Spicer style and double checking vendors for parts. The Toms kit seems to be much less, more complete but back ordered. NAPA for local parts is 4 times the cost. What am I missing here? Is it domestic quality made in the usa vs china junk?

 

[Yeller]

For the labor and parts cost I usually just take mine to my local driveshaft shop. But I’m spoiled they are next door to my office at work.

Driveshafts Inc

As for the parts yes you are on the right track. As for the quality, don’t know. They are common to all of the domestic OEM’s at one point or another.

 

[lars]

Adding to what Yeller wrote... Driveline shops tend to be pretty common in regions where there is a lot of ag and related industry. The one near me always uses Spicer parts unless requested otherwise. I bring them my rear, which I'm hard on, every couple of years. Usually needs a u-joint or two. They re-use everything possible though sometimes it means starting over. In any case I get a straight, balanced driveshaft back that I don't have to think about. I've seen what happened when a double cardan let go at freeway speed. It was really angry.

 

[Yeller]

Adding to what Yeller wrote... Driveline shops tend to be pretty common in regions where there is a lot of ag and related industry. The one near me always uses Spicer parts unless requested otherwise. I bring them my rear, which I'm hard on, every couple of years. Usually needs a u-joint or two. They re-use everything possible though sometimes it means starting over. In any case I get a straight, balanced driveshaft back that I don't have to think about. I've seen what happened when a double cardan let go at freeway speed. It was really angry.

I've seen failed pins and ujoints in double cardan's destroy transfer cases, transmissions and engine blocks at highway speeds from the violence of the shaft whipping around. It is pretty sad to see a broken atlas, AX-15 and engine block from a failed driveshaft, very violent chain reaction. Not saying this is common but has happened.

 

[jim3326]

Take it to a driveline shop. The cost is minimal compared to the option. And it will be balanced, unless that's what you do.

 

[TX-ZACH]

Will do guys.. Thanks for the comments.