Looking at changing the oil in the rear diff on my 05 3500. The truck is used in the summer only, and occasionally pull a 34' fifth wheel long distances up long steep grades at times.

I notice a light howl from the diff under load.........think it's possibly the pinion bearings since this is a high mileage truck. I've already replaced the diff and wheel bearings.

At our shop the big commercial trucks use 85/140 synthetic in the diffs..........is 85/140 GL5 synthetic okay or is it better to go with the lighter 80/90?

 

75/90 is the recommended spec for ALLLLLL applications GL5 100% synthetic. SOme run 75/140 who tow in hot weather.

 

Yeah, I've been running 75W140 Redline... It can get over 110 here.

 

I use servere gear 75-140 synthetic Amsoil!

 

Sounds like a heavier weight gear oil application to me.

 

I'm running the 75w-90 mobil 1 (available at the parts store) and a mag hytec cover, 8 quarts total. I have no concerns about the rear end not having sufficient lubrication in the Phoenix heat.

The heavier weight oil won't hurt anything, but you may find your mileage drops a couple tenths per mpg.

 

Okay thanks, perhaps I should look into the mag hytec cover as well.

 

There are other "extra" capacity covers out there available for our axles, and at a lower cost. I myself like the look and the integrated o-ring seal they use in their design.

 

I like the MH dip stick so I can easily inspect the fluid without draining it.

 

I run the PML rear cover in mine and it's about 100 bucks. Adds 1.5 quarts and really nice looking. Available in several finishes.

 

This one?

http://www.yourcovers.com/diffcover_10361.php

As-cast finish
$190.00
Black powder coating
$235.00
Polished finish
$300.00

This American Axle rear end differential cover fits some 2003 and newer Dodge Ram 2500 and 3500 and it fits GM trucks Silverado and Sierra 2500HD & 3500 with the Duramax or 8.1 engine.

The Dodge Ram 2500 and Ram 2500 may have a 10.5-inch or an 11.5-inch ring gear. (See our AAM 10.5, 14 Bolt for Dodge differential cover if you have an 10.5-inch ring gear - click here.) Check the identification sticker in your glove box or on your driver's door to determine which differential you have.

For the Chevy Silverado and GMC Sierra 2500HD & 3500 with Duramax or 8.1 engines, PML offers a choice of two differential covers for the rear end. See also PML P/N 9511 for different styling and 1 quart over stock increased capacity. Click here for the 9511.

This diff cover has oil fill, level check, and drain holes to make it easy to follow the 15K oil change interval that Dodge specifies for the AAM axles used in 2003 and newer Ram 2500 & 3500 trucks.

This cover also has an undrilled boss for a temperature sensor. Please call to order if you would like the boss drilled and tapped.

PML also makes a cover for the front differential on Dodge Ram trucks. Click here for information on the AAM 9.25" Ring Gear, 14 Bolt differential cover.

Volume: 0.75 qt. over stock



Looks ok, like the factory cover from my Nissan Titan, but the MH is definately worth the extra $80 over the as cast PML cover IMHO. The MH has the o ring seal, dip stick, and holds ~3 quarts over stock.