Driveline Slop Question

[eric1514]

I crawled under the Jeep this morning just 'cuz and I grabbed the rear driveshaft and I could rotate it back and forth about a quarter of an inch. I thought the noise from the rear end in my car was a warn pinion bearing. I'm thinking now I may have excessive backlash instead. I crawled onder my Chevy Silverado and the driveshaft is not moveable.

So the question is, should the driveshaft have that much play in it?

 

[Overlander BC]

Sounds like you need new U Joints.
There's 2 sizes. Make sure you get the correct ones.

 

[eric1514]

Sounds like you need new U Joints.
There's 2 sizes. Make sure you get the correct ones.

I thought so too, at first, but all the slop seems to be in the differential. The u-joints are tight and there is no slop between the driveshaft and the pinion yoke. I just don’t know how much slop I should be able to feel.

 

[Overlander BC]

I thought so too, at first, but all the slop seems to be in the differential. The u-joints are tight and there is no slop between the driveshaft and the pinion yoke. I just don’t know how much slop I should be able to f

Wait i

I thought so too, at first, but all the slop seems to be in the differential. The u-joints are tight and there is no slop between the driveshaft and the pinion yoke. I just don’t know how much slop I should be able to feel.

Was it in neutral when checking the driveshaft?
A rear dif shouldn't have much slop at all if the tires are on the ground. Backlash should be 0.006" or less

I thought so too, at first, but all the slop seems to be in the differential. The u-joints are tight and there is no slop between the driveshaft and the pinion yoke. I just don’t know how much slop I should be able to feel.

 

[24turbo]

Spider gears themselves and slop in the splines of the axles in the spider gears make it seem like there is lots of slop. Mine *probably* isn’t much different than yours. Mine makes a bit of noise when on light throttle but has done that for the past 2 years and hasn’t gotten any worse. I’ve changed the oil and there isn’t more on the magnet then I would expect. Backlash is .010 which is top end of the spec. I have 360 000 kms on it. Drop the cover and you’ll see what I mean how sloppy the spider gears are.

If yours has a howl it probably is the pinion bearings, (possibly combined with the backlash) but if it has 1/4” slop because of worn pinion bearings,the bearing would be destroyed and you wouldn’t be driving it.

I would bet you could change every bearing in the diff and it would have no noticeable change in slop.

 

[michael mehle]

My 07 is the same slop. Shifting from reverse to drive can slam pretty hard if I'm not careful. Thoughts? TIA

 

[Overlander BC]

So today I got under mine and dropped the main driveshaft to do the U joints. And checked how much play the yoke has. I'm estimating about 1/4 to 3/8 of an inch of play. And it feels normal to me. Hope that helps a bit man.
Got the new U joints in, greased, torqued the flange bolts to 85 ft/lb.
Only destroyed one 18mm deep socket to pound the cups out. They were in there. I think they were the originals.
Drives like brand new now. No more vibration. The whirring noise on deceleration is gone. The old U joints were so bad the driveshaft could move enough to go clunk clunk clunk

 

[eric1514]

My 07 is the same slop. Shifting from reverse to drive can slam pretty hard if I'm not careful. Thoughts? TIA

Mine does the same. Pretty good clunk with my foot on the brake and shifting into reverse or from reverse to forward.

 

[eric1514]

So today I got under mine and dropped the main driveshaft to do the U joints. And checked how much play the yoke has. I'm estimating about 1/4 to 3/8 of an inch of play. And it feels normal to me. Hope that helps a bit man.
Got the new U joints in, greased, torqued the flange bolts to 85 ft/lb.
Only destroyed one 18mm deep socket to pound the cups out. They were in there. I think they were the originals.
Drives like brand new now. No more vibration. The whirring noise on deceleration is gone. The old U joints were so bad the driveshaft could move enough to go clunk clunk clunk

I don't have the vibration but it definitely makes a whirring noise when I coast. That's what led me to thinking it was the pinion bearings. If you eliminated that sound with new u-joints, I might try that first. I think the joints are original so even if it doesn't fix my noise issue, they could stand changing anyway.

Any brand recomendations?

 

[Overlander BC]

I don't have the vibration but it definitely makes a whirring noise when I coast. That's what led me to thinking it was the pinion bearings. If you eliminated that sound with new u-joints, I might try that first. I think the joints are original so even if it doesn't fix my noise issue, they could stand changing anyway.

Any brand recomendations?

I'm not sure about brands, but if you get made in USA, it's usually tough and long lasting. I only get greasable joints. (Tip- remove the grease fitting before removing the old u joints). One thing is for sure, U joints are relatively cheap and easy to do and if they've not been done in a while, it's easier now than in January. If it makes rhe noise go away, awesome. It really is preventative maintenance.
Oh, and mark the driveshaft components before removal so it's easy to put together again in the same alignment. I usually use a series of F's for the front, a R's for the rear with a paint pen or something.

 

[Puddle Jumper 2.0]

I used Dana/Spicer joints as they are the OEM supplier for Jeeps and yes to above…… front and rear joints are not the same. More “Jeep Wisdom” from the wonderful automotive engineering folks………

 

[Overlander BC]

Actually Spicer is a good brand. Thinking back I put 6 of them in my old YJ and they never failed. They're probably still in it being enjoyed by the new owners.

I used Dana/Spicer joints as they are the OEM supplier for Jeeps and yes to above…… front and rear joints are not the same. More “Jeep Wisdom” from the wonderful automotive engineering folks………

 

[Shankster]

Agree with 24turbo - if it's time for a fluid change anyway I'd pop off the cover and give everything a once over - it may just be the overall play within all the parts of the diff. When I first bought my Liberty (with 125k miles) the diff was noisy and had a lot of slop - it turned out the bolt for the cross pin shaft was sheared off. If you end up needing a diff rebuild you might consider putting a locker or LSD in there while your at it (I have a good PowerTrax LSD on the shelf if interested) - with all the labor cost or effort to rebuild a diff you might as well get an upgrade out of it.

 

[Overlander BC]

Agree with 24turbo - if it's time for a fluid change anyway I'd pop off the cover and give everything a once over - it may just be the overall play within all the parts of the diff. When I first bought my Liberty (with 125k miles) the diff was noisy and had a lot of slop - it turned out the bolt for the cross pin shaft was sheared off. If you end up needing a diff rebuild you might consider putting a locker or LSD in there while your at it (I have a good PowerTrax LSD on the shelf if interested) - with all the labor cost or effort to rebuild a diff you might as well get an upgrade out of it.

Yup, anytime a labor intensive job underway- upgrade while there. 100%
I had an LSD in my old YJ and it was a godsend at times. Just had to use the right dif oil additive and it was great. No turning chirps, but when it needed traction, it delivered