rear axle howl: inexpensive fixes?

[dusterbd13]

Ive got a 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 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

[big gear head]

Check the pinion nut first. It is comon for the nut to back off and allow the pinion bearings to be loose. If the nut it loose then tighten it to about 150 foot pounds and give it a try. If the nut is not loose then see if the pinion has amu movement in it up and down or in and out. If it moves in any direction other than rotation then you have a pinion bearing problem and you must rebuild it. If everything is tight then you probably have a gear going bad, or a differential beaering going bad. In any case you will have to remove the chunk and find the problem and fix it. You didn't mention if you have the 741, 742 or 489 case.

[dusterbd13]

its a 489 case.

if i remove the chunk, how can i check to see if its the bearings or the gear itself?

michael

[big gear head]

The gears might show signs of wear, but it might be hard to tell. The only way to check the bearings is to remove the differential from the case so that you can see them. If you do this then you would have to check the backlash before removing it so that you can set it back the same way when you put it back together.