Wheel bearing noise.

[cams472]

Ok I know that it's almost impossible to diagnose a noise without actually hearing it but......I have a 93 Cavalier SRI 16V in great condition which was due a cam belt change three years ago. I parked it up outside and eventually got round to sorting out the belt and rollers etc a few months ago. Needless to say the discs had gone rusty along with a few other bits and pieces so I changed the entire braking system including discs, pads, shoes, handbrake cable. When I drove the car after it's lay up and subsequent work I could hear a rumbling noise just like the wheel bearings were shot. I was a bit surprised because these had been changed before the car was taken off the road. My MOT guy told me it was possible that water had gotten into one of the bearings and rusted it so both bearings were once again replaced........Much to my horror the noise is still there! The guy that changed the bearings told me that one caliper was binding very slightly and may be causing the noise but I am minded more towards some other bearing being shot. This has only appeared since being laid up and having the brakes changed. My thoughts are maybe a bearing in the gearbox (more specifically a diff bearing? ) anyone heard of these making this kind of noise? Are these prone to it? Is this an involved expensive job? The gearbox changes fluidly and makes no noise or whines. Would a slightly binding brake caliper produce the same noise? The noise is worse at about 30 and is very much like a worn wheel bearing It's a low hum changing slightly in pitch with each turn of the road wheels. Many thanks.

[Gaz]

Have you tried swapping the wheels round, ive had this before when there has been cheap tyres on.

[Squig]

do you mean a varing pitch when on the move or when turning, say, right?

[cams472]

Had the car up on stands today and ran it up in gear. The noise is almost certainly coming from the diff where the driveshafts go into the casing. I'm guessing this will be the diff bearings? I am wondering if it's going to be easier to locate a good secondhand gearbox or maybe get mine reconditioned, are the diff bearings easy to replace?. The Noise changes pitch with each turn of the wheel so it's an up and down drone, It is the same noise as I've heard many times when wheel bearings are failing. The noise does not alter when the car is cornered either way. Are these gearboxes for the 16V model easy to come by in good condition secondhand? Many thanks for the help.

[Envoy CDX]

are you 100% sure its the gear box? I had a rumbling noise after changing the discs and pads on the cav turned out to be the catch plate (on the back of the disc) was pushed in too far - see if thats the problem.

[Cavyman_130]

hows the clutch on it? if the thrust bearing is on its way out this will give off a rumbling noise.

[Squig]

second hand gearboxes vary in price dependant on model, however, I think yours will be either an F20 or an F18. Both are relatively cheap secondhand, but on the downside secondhand gearboxes can hide problems that you won't find until running.
so secondhand 'box is probably cheaper but reconditioned will be guaranteed for a while at least

check everything else first.

[cams472]

Thanks for the help here it's been appreciated. I think I'm pretty certain that it's the diff thats rumbling so I've decided to change the gearbox. How do I tell which box I have? Is there a more desirable box that will fit i.e closer ratios?

[Cavyman_130]

going by what you have said (93 SRi 16v) im guessing you have the redtop engine so your gearbox will be the F20 unit.