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Index > Engine/Drivetrain > Thread: Noisy rear diff
Thread: Noisy rear diff
Mazdarx605


Redlining
Posts: 314
posted June 23, 2014 05:49 AM

Noisy rear diff

Hey guys,

Over the past year I have noticed a strange noise coming from my truck, but only under deceleration. I have replaced the fluid in both the axle, and trans, but the noise is still there.

Last year I had a leaky pinion seal, and bought a new one. I didn't trust myself doing such a job, so I farmed it out to a local repair shop. I am now wondering if somehow they messed up the diff by not tourquing something quite right on the pinion.

Should I stop driving the truck? I really don't drive it much anyway, but should I totally stop before doing anything really major to the diff? Can I get this rebuilt by a axle specialist, and if so can they or I source parts for it? Could it be that the pre-load wasn't reset when they replaced the pinion seal. Is there a crush sleeve that wasn't replaced? I know I did furnish one to them, but I would assume they would get one if it were needed. Also I have a spare truck that is a project that may never be done. If I need to could I just use the diff from it in my truck? Both are 74 models.

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Brad


Rotorhead
Posts: 1672
posted June 23, 2014 08:48 AM

If it is making noise on decel and on light throttle it can be rear wheel bearings too. If you pull the rear brakes off and spin the hub you can hear it.

If they didn't set the pinion bearing preload, then the pinion bearings could be well either loose or too tight. Most likely they didn't do this, nor use a new crush tube. If you pull the rear end out you can check the preload yourself.

Finding a rear end shop that is both competent and takes pride in their work is hard to find. Most want to get paid and out the door.

You can swap the rear from your spare truck no prob.

Check out this webpage..lots of good info. Next time I'll ship it to Zuk and have him do it. http://gearinstalls.com/

       
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Mazdarx605


Redlining
Posts: 314
posted June 23, 2014 10:50 AM

If the pinion is too loose or tight does it mean I have damaged the differential or is it salvageable? Could I try a competent shop to just repair the possible loose tight condition and have them use a new crush sleeve? Are parts like the crush sleeve still available for these? Should I avoid driving the truck?

Thanks,

Chris

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Brad


Rotorhead
Posts: 1672
posted June 24, 2014 01:51 PM

The differential itself should be okay. Too much or little torque on the pinion nut will wear the pinion bearings quickly, which is what you likely hear. At the extreme the pinion teeth would not engage the ring gear teeth properly, and would accelerate wear of both parts.

I haven't found a crush sleeve available new. A shop who did my diff stretched the stock one out then installed and re-crushed it as needed.

If it's making a lot of noise I wouldn't drive it. At this stage I'd drain the oil and run a magnet thru it. Check the magnetic drain plug. If the fluid is silver or shiny then there's a big problem. Metal chunks a really big problem.

       
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Mazdarx605


Redlining
Posts: 314
posted July 28, 2014 03:49 PM

So I removed the differential in my truck today and found four large chunks of pinion teeth in the housing. I plan on using the spare diff I have, but I would like to rebuild this one. Anyone have a spare ring and pinion they would like to sell?

Chris

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