My dually's rear diff started clunking at takeoff, especially when towing our camper. I took it to a truck shop, since I know little to nothing about differentials. I got a call from them today and they say that my diff is just plain worn out. Side gears, ring and pinion gears are all worn badly. The bearings are also about shot, especially the driver's side carrier.

They quoted me three prices..

1) Only replace the side gears and bearings... $1,000 parts and labor. Pretty much, a "Band-aid" fix.

2) Replace the whole differential, with a rebuilt unit and new bearings... $1,600 parts and labor. Also includes a 1 year, unlimited mileage parts warranty.

3) Replace the whole differential, with an entirely new Jasper unit. $3,000 parts and labor. Includes a 3 year, unlimited mileage warranty. That warranty also includes parts, labor and towing.


Anybody have any other ideas??

 

I'm assuming it's a Sterling 10.5 rear.

A master rebuild kit with gears, trac-loc diff and carrier/pinion bearings is about $1,000. With the open diff and just the spiders and reuse your old carrier it's about $650.

New axle bearings with seals are about $250.

Then there's labor. Figure $5-600 to setup the rear and another $1-200 for the axle bearings.

So for a trac-loc rear that's around $2k. For an open rear figure $1,500-1,700 range...

Of course if you have a trac-loc carrier already (factory LS rear) then it'd be somewhere in between those two numbers if you just get clutches and spider gears and reuse your own case.

That's my back of the napkin calculations so #2 seems right on the money cost wise assuming it's an open rear and assuming they do the axle bearings too.

So you're paying an extra $1,400 for an extra 2yrs warranty...

Do you trust the shop that's doing the rear? I'm assuming with #2 they're going to rebuild it themselves.

If it were me, and I trusted the shop, I'd go with #2. Also, if I had an open rear I'd pop for a limited slip to drop in. But that's just me, not everyone cares for LS rears...

I would not do #1.

Also, make sure you break it in correctly. First 100 miles, keep the speeds down under 55mph and for the first 500 no towing, heavy loads or hard acceleration. Have the shop change the fluid at 500 miles and make sure everything looks cool. Then enjoy for another 300k miles...

 

Since it's a dually, isn't the rear a Dana 80?

 

I have no idea... But those are the prices for a 10.5 Sterling. Should be in the same ballpark as the D80 though. Enough for a quick napkin cost check...

Anyway, as long as it's setup right there should be no issues with it. Not in a year, not in 3, not in 10... Break it in correctly and make sure it's got a good pattern and it's not running hot (under 200*). Usually if something's going to happen it'll show up pretty quick. Change the fluid before the warranty runs out just to make sure everything's cool.

So it's up to you if you want to spend the extra money for the "extended" warranty. Just make sure you trust the people doing the rear.

 

Called the shop back today and they are doing the rebuild. Not the Jasper unit...

They are also doing the axle seals and using 75w-140 synthetic.. While they have it down, I'm going to get new rear brake shoes and pads.. The parking brake was getting kinda weak..