rear axle howl: inexpensive fixes?

Ive got a howling 489 case 3.55 clutch type sure grip in my 70 duster. (bought it used) i finally made up my mind that I'm not going to screw around with doing the explorer 8.8 swap, as i just hate c-clips. (had an axle exit the truck at work recently....)

so I'm starting to work on the 8.75. i fixed my rear wheel bearings today, which made things a lot quieter. still have the whine/howl under throttle, though. anything above maintenance of speed going downhill gets really, really loud. driving with earplugs or the stereo cranked up is just not an option, either. i like to hear myself think.

so, anyway, here's the question:

if the howling is due to improper gear mesh (according to google, that's what causes it under load), what can i do to fix it?

can i reset the gears with standard tools (i have all the dial indicators, calipers, micrometers, etc from when my dad built motorcycle engines)?

or, better yet, does the Lucas rear axle lube that guarantees to quiet noisy axles actually work?

worst case scenario, i have to pay the local drive line guys 800 to rebuild this thing. id prefer not to dump that kind of money at this point in time if i don't have to.

long story short, what kind of inexpensive fixes are there, or is it just shot?

Michael

My experience with this is that you'll need to setup the rear end properly to get it to stop making noise. I'm not experienced with the rear end you're talking about but you could also have a pinion bearing that is gone. You could pull the cover and check the meshing with some grease then try to adjust with different shims.

Mine made noise. When I pulled the cover to look, I didn't get "splash!", I got "glop". I put the cover back on and bought a new rear end. If the fluid left at any point, everything is toast.

Check the pinion nut. Change the lube make sure it has the skunk piss additive for the clutches.

Throw in a few handfulls of sawdust, then sell the car.

Start by wiggling the pinion flange. If you can move it up/down left/right any at all, I'd start haunting the junkyards because that means the ring and pinion have been running misaligned for a long time. No amount of bearing swapping will fix it, only a new R&P. New bearings etc will still mean the wear pattern is all wrong, meaning still noisy. The parts aren't that expensive, but setting the rear end up with the crush sleeve etc is sorta out of the realm of the average dude.

If its gear whine, which it probably is since it makes noise on drive but not on coast, you most likely need gears. As others have said, check pinion bearing play, but I'd not count on a lot of success there.

On the other hand, nobody ever died from a bit of gear whine. Bearing whine, yes, but I've pulled gears that howled like a bugger, and haven't been able to see why.

Unfortuneatly, if there are many miles at all on the gearset, they don't like to have their adjustments tweaked. If it's that bad, the 8.75 is easy to change the drop-out. Raise the car, pull the axle shafts, pull the carrier. Insert new (different) carrier, reinstall axles, new lube in, and car back on the ground. I've changed them at home in 45 minutes. Once I had to fight one axle shaft, but even that only took the process to 90 minutes.

Look for a same ratio, good gearset carrier, at a wrecking yard. You might even luck into a SureGrip for a few bucks. The most I've paid for a Mopar 8.75 punkin is about US$ 75, and that had a good SureGrip in it already. Another 20 bucks for the proper oil, and you're in it for a C-note.. That would even please my child-of-the-Depression old man.

The whole sawdust-and-peddle it is a little premature, IMHO. YMMV, as always...Good Luck!