Which half shaft is bad?

[Gordo]

I've got a vibration and low frequency hum while driving straight ahead. It goes away when turning left but stays the same when turning right. I suspect one of my front driveshafts is on the way out. Is there a good way to identify which one it is before I go through the motions?

Thanks....

 

[Sparky]

Probably not the half shaft as those don't typically hum. More likely a hub bearing, and probably the driver side. Or it could be a noisy tire also...

 

[davenay67]

^ +1

More likely to be a hub bearing than a half shaft. More expensive to replace, but much easier and quicker to do. Lift each (front) corner of the truck and feel for play at the wheel.

Driver side is likely the candidate, but I've had bearings fool me before and end up being the opposite side to what I thought.

 

[Gordo]

Probably not the half shaft as those don't typically hum. More likely a hub bearing, and probably the driver side. Or it could be a noisy tire also...

The drivers side bearing is new! Tires seem fine.

 

[navigator]

when my hubs were going out they were really noisy but when I took them off you couldn't really tell.

 

[Sparky]

Well it should be under warranty then... I had my new one go bad after only 15k miles I think it was. BUT also as davenay said, sometimes they fool you and the opposite one that you would think from the test is bad.

Try this - jack up the front end, crawl underneath from the front (leave the tires on), and grab hold of the coil spring one one side. Have someone else give the wheel a good spin. Then do the same on the other side. If the hub bearing is bad enough you'll feel a raspy vibration in the spring on the bad side. When I had my bearing go out on me again I had the shop check it out (their warranty work) and he showed me this trick. Now mine was really bad and quite loud so I don't know if a mildly worn one would do this or not, but worth a shot.

A noisy tire won't necessarily show anything externally. The tires that were on my TB when I got it were rather noisy, almost bearing-sounding, until I replaced them. My parents have Mastercraft Courser tires on their vehicle and one recently within the last few thousand miles started making quite a racket. Thought it was a bearing until he rotated the tires and the noise followed the tire. Nothing appears to be wrong with it other than the noise. You could try rotating the tires and seeing if that makes a difference up front.

 

[navigator]

mine sounded kind of like I had mud tires on.

 

[strat81]

when my hubs were going out they were really noisy but when I took them off you couldn't really tell.

Same here. The "grab the tire and move it" test showed a solid bearing. But, it was noisy as hell.

I recall reading that proper retaining nut torque is important for longevity. If the bearing was replaced and someone cranked it to 87,000 foot-pounds, that might cause a problem.

Also, not all bearings are equal. eBay is chock full of crap bearings. "New" doesn't mean anything is the new part was lousy.

 

[HARDTRAILZ]

Quite unlikely a half shaft is bad. Check the wheel bearings. If you just had one replaced, it is fairly likely the other one needs it.

 

[davenay67]

Same here. The "grab the tire and move it" test showed a solid bearing. But, it was noisy as hell.

I recall reading that proper retaining nut torque is important for longevity. If the bearing was replaced and someone cranked it to 87,000 foot-pounds, that might cause a problem.

Also, not all bearings are equal. eBay is chock full of crap bearings. "New" doesn't mean anything is the new part was lousy.

True dat..!!

I went with Moog bearings (3 yr guarantee) and used a torque wrench to get the exact torque setting when I had to replace both front hub bearings within a few months of each other.

 

[strat81]

While you are inspecting everything, check the boots on the CV joints. It is possible that one has ripped, leaking the grease out.

 

[McGMT]

As was said proper torque on the shaft nut is critical to making these last as long as possible.... Most people either don't know, or don't believe it matters but it really does, especially on these sealed hub bearings...

103 ft lb

 

[Gordo]

Found it! Passenger side wheel bearing. I put it on my hoist and ran it in 4 wheel drive. Right front it is! Only the right front was spinning in gear and the noise was there so I blocked the right wheel to force the left one to turn. It was silent.
Turned the engine off, give both calipers a rap with a hammer to realease the drag and spun each wheel while holding the coils spring. This little trick works! Left was perfect but the right could be felt through the spring!
New one on order!

Thanks for the tips guys!!

 

[Sparky]

No problem

Good thing is those hub bearnings aren't a hard replacement. Make sure you torque the axle nut properly - it only takes about 103 ft lb, same as the lug nuts.