Gear Noise

[broncokak]

I've been hunting for a noise for the last few weeks and have narrowed it down to the rear carrier. The noise sounds like a typical gear howl only now as loud and there is a slight vibration with it. It is intermittent and happens both under power and during coast. Usually just tapping the throttle will make it stop. I've pulled the 3rd member out and am running my spare and have no noise or vibration.

Looking at my gears and bearings, everything looks good. What am I missing? I'm running an ARB, could the problem be in that?

 

[broncnaz]

Highly doubtful the ARB has anything to do with the noise. Some gears just make noise. How did the back lash feel? Patterns look ok but drive side pattern looks a little high on the gear. Might need a backlash adjustment. also I would expect the contact surfaces to be shiny those look rough might just be the pics tho as the pinion looks shiny. How did the oil look any shiny stuff in it? blackened?

 

[broncokak]

Backlash is fine. I should have added the gears are less than a year old as well. I swapped ratios last September and used a new install kit with Timken bearings.

 

[bronconut73]

Gear name brand?

Some of those racing gears (like Richmond) are kind of noisy...super strong but noisy.

 

[broncokak]

Oil looked like it has some fine metallic particles in it.

 

[broncokak]

Can remember the brand right off hand but I have the box in the garage. They came from Tom's Bronco Parts I think.

 

[broncokak]

4.88 ratio if that matters.

 

[bronconut73]

Oil looked like it has some fine metallic particles in it.

Well....I know that looks bad but it seems like you would expect to see a little metal during break-in....right? I think you have to replace your gear lube after the first 500 miles of ring & pinion break-in for that very reason.
Just trying to be optimistic here....

 

[bronconut73]

Can remember the brand right off hand but I have the box in the garage. They came from Tom's Bronco Parts I think.

Tom's wouldn't sell us those loud racing gears so that must not be it.....
Hmmmmm.....

 

[Yeller]

how's the preload on the pinion bearings? I had them be too loose and make all kinds of weird noises, not so light that it felt loose but not enough to keekp the bearings from making noise. I'd also closely check the pinion yolk I've had them get sloppy at the ujoint and cause all kinds of weird noises and vibrations.

As others have said could be a noisy gear set but usually that doesn't vibrate, or come and go.

 

[broncokak]

I know I put more than 500 miles on before the lube change. And the are Motive Gears so they must have came frome the Graveyard and not Tom's.

 

[Yeller]

Motive usually produces nice gears. But things do happen, we put a new 3rd in the U4 for the last race and didn't get a lap in prerunning before the pinion snapped between the bearings, so things do happen.

 

[Justafordguy]

X2, the pattern looks high on the drive side to me.

 

[broncokak]

how's the preload on the pinion bearings? I had them be too loose and make all kinds of weird noises, not so light that it felt loose but not enough to keekp the bearings from making noise. I'd also closely check the pinion yolk I've had them get sloppy at the ujoint and cause all kinds of weird noises and vibrations.

As others have said could be a noisy gear set but usually that doesn't vibrate, or come and go.

Preload seems fine. I used a shim instead of a crush washer. The yoke has some slop on the splines but that seems to go away when I torke the pinion nut down. I can check the preload again, it was good when I installed the new bearings last year but maybe with some miles on it now it could be a little loose.

 

[welndmn]

The wear patten on the ring gear looks like it's been run low on oil, the pictures don't show a normal wear spot, but scratches. This can also be caused by junk in the oil.
Good chance that noise will never go away with that patteren. A thicker oil like red line shock proof might help lower the noise.

 

[needabronco]

While your gear pattern looks acceptable by most shop standards, it could be better! You might do some adjusting and see if your noise goes away. 9" third members are easy to setup so it shouldn't be too big of a deal to do.

 

[broncokak]

The amount of oil was fine, never ran low. The housing doesn't leak nor the pinion seal.

 

[JWMcCrary]

You said backlash was fine, but, is there some room left to tighten it up and still be in spec? If so I would do that with fresh oil and give it try.

 

[broncokak]

I could tighten the backlash a little more I think, but not much.

 

[welndmn]

The amount of oil was fine, never ran low. The housing doesn't leak nor the pinion seal.

The pictures just looked like they had overheating, oil being the common one.
Does the wear patteren of the gears have little scores in it, or just a camera trick?