New axle bearings and seals

76BBSub · July 31, 2001

Have had an extra rumble in the Suburban for a few weeks now, and couldn't figure it out. I was under the truck last week and saw diff fluid had been leaking out of the driver's side axle seal and splashing radially out from the tire. I figure the axle bearing is making the rumble and the seal is the leak, so I bought a new set for both sides. Also rented the puller tool (slide hammer) and bought a bearing and seal dolly to help knock them into place.

Has anyone done this job on an older 12-bolt? It's not a full-floater, so according to the Haynes it can be done at home. I did this on a '77 Jeep Cherokee (old, big body style, not the "new" one) and it wasn't bad.

Any thoughts or experiences would be appreciated. This is my Friday project...

Jeff

76BBSub · August 4, 2001

The new axle bearings and seal are installed, and I have done the obligatory "test drive".

WOW, this baby is way quieter than before, I guess those bearings had been running thin for awhile. The only problem...now I can hear the various wind noises and squeaks a little more clearly...character, right?

Anyway, I took a couple digital pictures, so I think I'll do a tech page on this in case anybody is interested.

Later,

Jeff

gmcblu · August 4, 2001

Ah, yes, gotta love that "character."

76BBSub · August 6, 2001

Yep...tons of character now...mostly wind noise. I had been trying various undercoatings and even bought some heat shield/sound deadening material to fight the road noise. Turns out it was mostly the bearings going bad. Now if you let up on the throttle at pretty much any speed the only noise you hear is the wind noise in the vent windows, and a little bit of tire hum on the concrete highways around Houston.

Guess I'll just turn the radio up!

PS. If you're in the throttle all you hear is 454 cubic inches through the headers!!

Jeff

76BBSub · August 14, 2001

I was hoping to see improved gas mileage with the new bearings installed, I figured metal on metal at the rear axle was eating up a mile per gallon or so....

Nope.

Filled up last night after 350 mosly highway miles, still only 10.5 mpg, which is what I was getting before.

Oh well, at least it's alot quieter inside the truck....

Jeff

jsims · August 16, 2001

Jeff,

thanks for the site tip, cool forum...regarding bearings...I may have a similar noise somewhere in the rear...but it only whines when I back off at fairly high speeds. Sort of a whining hum. No splashing oil or grease, just a little damp around 12 bolt diff.

76BBSub · August 16, 2001

Actually, that sounds more like front wheel bearings. When you let off the gas more weight shifts to the front end, so if your bearings are a little worn they'll make some noise. If it's the rear bearings they'll probably eventually leak, one of mine did, and you'll see the diff fluid on the backside of the brake assembly and radiating out from the center of the back of the tire. I don't know of an easier way to check it, though. Could also be inside the diff. You'll probably have to wait until it gets worse to really diagnose it.

Jeff