Rear axle noise

[The_Handier_Man1]

From: poppinjohnnies  (Original Message)
Sent: 5/25/2005 4:16 PM

The rear axle in my '78 Chieftain has been howling since the day I bought it.  Oil is good, hub bearings are good.  I believe that the carrier bearings have worn thus wearing out the ring & pinion gears.  I have access to a good rearend from a '73 Chieftain.  The only difference that I can tell between the two (so far, anyway) is that the '73 has 5 lug nuts and my '78 has 8.  Will this be a problem or can I just swap out the hubs?



From: denison
Sent: 5/25/2005 8:18 PM

I dont know. You would have to establish that both axles were the same series, then check part numbers for the differential parts in the part catalog for the two chassis. There should be an axle # on the back side of the differential housing. On the curbside below the axle tube centerline is where it is located on mine. If the axles are both HD60 or HD70 or whatever, then it -might- be feasible, but the driveshaft might be a different diameter, and have a different sized yoke for the universal joint on the end of the pinion shaft.
The mattter of changing the hubs would also involve the diameter and the width of the brake drums and brake shoes, and the different type of brake system. I am about positive the 73 and 78 would have had different wheel cylinders and brake plumbing to the rear axle, possibly different parking brake set up also. I dont know about the possibility different wheel bearings.

If the noise from the differential is a ringing noise, its a common sign of wear and lack of pinion to bevel gear preloading. This can happen from poor set-up, or from wear or having sat with too much water in it. The adverse wear can happen quickly if the differential was run very low on fluid, otherwise it would take hundreds of thousands of miles. It is possible the noise would be less if you had the differential adjusted with the proper shims - at which time you could check the carrier axle bearings and the condition of the pinions inside. We did this with my F1 pickup truck that had 350k miles on its rear axle. Afterward I could still hear the ringing, but it was a lot softer. The bevel gear had slight grooves in it, matching the pinioin gear of course; no metal shavings in the differential oil though. With the axle completely off the vehicle, it was still a lot of work, and took a couple of special tools I didnt have, as well as the dial indicator, etc.