My 1995 Bronco has developed a noise from the rear axle. I disconnected the rear shaft, drove it and the noise was gone. I found a bad u-joint, replaced all three and the noise is still there. I narrowed the location down to the axle. Could this be a bearing? Or something worse!!! She has 107,000 miles on her. Has anyone have a hunch as to what I may be looking at?

All help is welcomed.

 

What kinda noise is it?

Because since ive had my truck, ive had a whine in the rear when im off the gas or 1/15 on the gas, but when im giving it a fair amount of gas, the noise subsides. And im wondering what that could be.

It is a clud, whine, bang?

Adam

 

Does the noise change with vehicle speed or when giving/letting of the gas? From my experience if it changes with the amount of gas it’s a bearing going out.

 

Sorry for the weak description.
It is more of a thumping noise. Almost like a rock caught in the tire, it increases with speed. No vibration yet, so I am leaning towards a bearing. Any idea as to what bearing? Wheel, pinion??? I am discounting any severe damage, as the problem slowly arose, not brought on by misuse or abuse.


1995 Eddie Bauer, 5.8L, 7" lift, 37" MTR tires.

 

If the noise is speed related, and you are wondering if its axle or pinion bearing, keep in mind that the pinion is gonna be spinning faster than the axles so if the rhythmn is faster than it should be per tire revolution, then you may be dealing with pinion bearing(s). If its about in time with tire revolution look to the axles.

Ahh just read your signature...with 37's I'd go for wheel/axle bearings first.

 

your thump is a broken ring gear or pinion gear tooth. take off the rear end cover and check the ring gear for missing teeth. it may also be the pinion, but you might not be able to access that. look for metal shards in the fluid. if this is the case, you need to replace the ring and pinion.

 

ayoungblood: your noise is either extremely worn ring and pinion gears or bad pinion or carrier bearings. if your ring and pinion gears have been recently replaced, they are out of adjustment. there is too much backlash in the pinion gear, and that is causing your whine.

 

So you have any idea how to go about doing that?

Adam

BTW, its like a whine/hum.

 

if you aren't a seasoned mechanic, i would not recommend messing with ring and pinion measurements. It is an art. With the driveshaft disconnected, try turning the pinion yoke back and forth VERY gently. you should feel a small gap between the point where the ring gear is pushed clockwise and where it is pushed counter-clockwise. this gap should be so small that it is very difficult to recognize. a large gap causes the whine you hear upon gentle acceleration/coast and also causes premature wear of the gears. again, i would recommend having this checked by an autorized mechanic.

 

I just replaced my spider gears for a whine and thunking. They were definately the culprit, as they were chipped and cracked. When you crack the case, check them too! Dealer price is under $50.

 

Just remove the cover and inspect everything you see inside. Mine had a missing tooth on the ring gear, loose bearings and badly worn spider gears. Even if someone else does the work, you want to know what needs to be done in order to get good estimates.

Jim

 

I had a similar problem. I put the truck on jack-stands and ran the truck while I used a broom stick on the rear axle housing and put it to my ear. Yes it sounds stupid but works. I narrowed it right down to the diff and the bears had gone.

 

I had a similar "Thumping" noise in the 9" rear in my 1984 Bronco.... I wound up chipping off a few ring teeth.. and the end support bearing on the Pinion was shot...

I believe I helped it along... because I do have the 460... and the C-6 has the AOD 1st/2nd gear set... and sometimes... I actually drop it down into 1st manually when doing about 30... and then hammer it... So with this rear end I am not going to be doing that so much... hahaha

 

Youngblood:
Are you sure your noise isn't just the fuel pump? I hear a similar sound in mine but I assume it is just the fuel pump doing its thing.

 

What luck! I was just going to post the exact same question! My 88 (with 351 and 33x12.50) is now making a thumping noise, most pronounced at slow (10 mph) speeds. When I go into neutral while moving the thumping stops. I did this to simulate no drive shaft spinning. Back into drive and the thumping starts again. Maybe dropping into first to help slow down on hills wasn't a great idea after all. So, consensus here, what might be broken, and what to do to fix it?