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Driveline Vibration??

2K views 5 replies 3 participants last post by  xblowhard 
#1 ·
My 02 SD 4x4 has a growing vibration problem...seems to be most noticeable under light throttle around 45 mph. I've been suspecting u-joints or center driveshaft support bearing. Tires are @ 70 psi, lug nuts are 150 ft lbs. Removed driveshaft today to check u-joints, center bearing. They are all good. One thing concerns me and that is, with gear selector in "N", 4-wheel drive UN-selected, engine off, all wheels free to spin, it takes both my hands to rotate the driveshaft. Clockwise, it's noticeably harder to turn than counter-clock, but even that direction surprised me. I'm wondering if I have a bearing going out in the transfer case or maybe the tranny. What I'd like to know is this: What am I rotating when everything is in neutral? Front driveshaft easily turns the front axles.
Last thing before coming in for dinner tonight: Wheels are up in the air-I decided to check tire run-out. Three were close to "0" but the Right Rear had .300" out of round!! Almost 5/16". There's my vibration. (I think) But what about the driveshaft rotation resistance?
Sorry about the wordy post ... Can't seem to adequately express myself in 10 words or less.
 
#2 ·
If the t-case is in neutral and you're trying to turn the driveshaft with both rear wheels off the ground while still attached at the t-case and differential, you may just be feeling brake drag, although you have a nearly 4 to 1 advantage in turning the driveshaft over turning the wheel (by the hub - not the tread of the tire, which would be much easier because of the leverage.
 
#3 ·
I was lying under the truck, all wheels free, T-case NOT in 4 wheel drive (in neutral, I guess==It's shift on the fly). Turning the driveshaft by hand-it takes more twisting force than I expected. What is turning inside the t-case & transmission?
 
#4 ·
I don't believe that the ESOF t-case has a neutral position. So you were turning the t-case and the output section of the tranny as well.
 
#5 ·
I read in the manual once how to get the ESOF into neutral; it is an entire wiggle your toes and touch your nose process. So, you were likely in 2-hi.
If you think you might have something wrong in the diff I'd pull the cover. It's probably time to change your fluid anyway so even if nothing is wrong it won't be a wasted chore. Make sure to use the friction modifier additive.
If there is no lateral play at the trans output or diff input then chances are you are good on bearings.
 
#6 ·
Problem solved

Thanks guys. Sorry for being slow to get back to the forum. Further investigation revealed a right rear tire has a tread bulge of 5/16" that I finally spotted when I checked eccentricity with a dial indicator. (It was actually .300") Put my spare on and took my Wife & 2 Beagles for a ride and all aboard gave the ride a 5-Star approval rating. Looks like I'm in the market for 4 Michelins tomorrow since my old tires are more than half gone.
After the password thing that happened to this site a short time ago, it appears that when I reset my account, my profile is missing. I plan to take care of that as time allows--maybe I'll go premium soon as well. This is a very helpful bunch on the Diesel Stop.
Emmitt
PS ... How come I'm not getting email notifications re new posts?
 
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