Wheel bearing or front diff?

[l3n0x]

So my 100 has developed a strange growling sound.. It happens around 40-60mph & goes away above or below that. Interestingly if I'm slightly turning to the right (like a long right curve in the road) it goes away completely. But when going straight or turning left it is there. If I put the transmission into neutral it still remains, so I think it's not engine related.

A couple miles (~6-7k) ago I've did a leaky front diff input seal on the car, just trying to put the nut back where it was, so the preload on the pinion bearing is probably not perfect.
Also if I lift the car & shake the wheels 12 - 6 or 3 - 9, I can't feel anything loose (except for the waaay long gone steering rack, but that's a different story)

I'm wondering if it is a wheel bearing or the front diff? I don't have an idea how to diagnose it..

 

[RedesKat]

So my 100 has developed a strange growling sound.. It happens around 40-60mph & goes away above or below that. Interestingly if I'm slightly turning to the right (like a long right curve in the road) it goes away completely. But when going straight or turning left it is there. If I put the transmission into neutral it still remains, so I think it's not engine related.

A couple miles (~6-7k) ago I've did a leaky front diff input seal on the car, just trying to put the nut back where it was, so the preload on the pinion bearing is probably not perfect.
Also if I lift the car & shake the wheels 12 - 6 or 3 - 9, I can't feel anything loose (except for the waaay long gone steering rack, but that's a different story)

I'm wondering if it is a wheel bearing or the front diff? I don't have an idea how to diagnose it..

I'd assume it'd be more diff related if there is no play /movement in bearings. I'm no master but I've heard the differential preload / backlash is pretty key and is a tricky thing to get perfect which could be why you're hearing a whine

 

[l3n0x]

I'd assume it'd be more diff related if there is no play /movement in bearings. I'm no master but I've heard the differential preload / backlash is pretty key and is a tricky thing to get perfect which could be why you're hearing a whine

It's not a whine, but a humm

 

[AlpineAccess]

Spindle Bearings were brought up in another recent thread as a potential source for a humm like this.

 

[UncleJakeNZ]

It could be worth moving the rear wheels and tyres to the front axle to eliminate a tyre hum first . If your steering rack has play it could be messing with front tyre wear .... which can do strange things between certain speeds

 

[abuck99]

Mileage? Service history? Last time bearings repacked & serviced ?Original or aftermarket CV axles in use? These are all important things to include when asking for help.

The fact that you didn’t reset bearing preload after replacing diff seal points towards bearing preload issues. Curious- Did you re-use inner and outer snap rings, lock washer when you reassembled?

I’d also check the CV axles for remarkable play per FSM procedure: in/out, up/down. There’s an illustration showing it. The low pitch rumble you described oftentimes presents in worn cv’s before they start clicking.

 

[JunkCrzr89]

A couple miles (~6-7k) ago I've did a leaky front diff input seal on the car, just trying to put the nut back where it was, so the preload on the pinion bearing is probably not perfect.

I’d wager that this is at least partially the culprit. IIRC, preload for a reused pinion bearing is like 50% lower than for a new bearing, and it’s possible that the bearing and/or spacer needed to be replaced (ie, cause of the oil seal leak) to get the preload set properly.

It could be worth moving the rear wheels and tyres to the front axle to eliminate a tyre hum first . If your steering rack has play it could be messing with front tyre wear .... which can do strange things between certain speeds

But this was my first thought as well. Have your tires rebalanced and rotated and see if the sound goes away.

 

[nissanh]

You said the sound goes away when turning right. This makes me to believe it could be a bearing as the load relaxes on the bearing that makes the noise when making a right turn hence no sound. Turning left should intensify the noise.

Did you check the bearing play white the wheel is on? If not try with the wheel on between 12 and 6 O clock. Keep the truck on jack stands. You don't want the vehicle to fall when your hand is at 6 O clock position.

 

[l3n0x]

You said the sound goes away when turning right. This makes me to believe it could be a bearing as the load relaxes on the bearing that makes the noise when making a right turn hence no sound. Turning left should intensify the noise.

Did you check the bearing play white the wheel is on? If not try with the wheel on between 12 and 6 O clock. Keep the truck on jack stands. You don't want the vehicle to fall when your hand is at 6 O clock position.

That's what I've tried & can't feel any play.

 

[l3n0x]

I’d wager that this is at least partially the culprit. IIRC, preload for a reused pinion bearing is like 50% lower than for a new bearing, and it’s possible that the bearing and/or spacer needed to be replaced (ie, cause of the oil seal leak) to get the preload set properly.



But this was my first thought as well. Have your tires rebalanced and rotated and see if the sound goes away.

Unfortunatelly it's not possible to replace the spacer/bearing without pulling the whole diff apart.. Which wasn't an option for me. Neither do I have the skills or the tools to do it, and don't have the money / trust to outsource it.. Mind that I'm living in a 3rd world country.

 

[l3n0x]

Mileage? Service history? Last time bearings repacked & serviced ?Original or aftermarket CV axles in use? These are all important things to include when asking for help.

The fact that you didn’t reset bearing preload after replacing diff seal points towards bearing preload issues. Curious- Did you re-use inner and outer snap rings, lock washer when you reassembled?

I’d also check the CV axles for remarkable play per FSM procedure: in/out, up/down. There’s an illustration showing it. The low pitch rumble you described oftentimes presents in worn cv’s before they start clicking.

It's the input seal (where the propshaft is), not the output ones (where the axles are). I don't know when the wheel bearings were last serviced, or anything about the life of the car before my ownership (last 2 years & 10k miles out of 20 years & 400k miles).
There is some up/down play in the CV axles though on the diff side.

 

[ramangain]

I'd wager you are (over)due for a front wheel bearing service anyways.

 

[Live to Ski]

Just got my fronts repacked. Yota tech says the were never serviced (140k miles). No surprise there.

So I'd follow ramangains advise.