Servicing the Axle locking Differential

pointhalifax · May 30, 2002

My 2001 2500HD has the locking differential.It was to be serviced at 5000 kilometers and again at 25,000 kilometers.

The dealer says that they do not do the initial servicing because it is not necessary.

What is involved in servicing the axle locking differential?

Really appreciate this site and the expertise it represents.

Thanks for your help.

Point Halifax

JimDandy · May 30, 2002

The servicing is a fluid change. Rather simple, but tedious task. A new gasket (if using synthetic, otherwise RTV is fine) and 4 quarts of gear lube, if you plan on taking cover off. I used Mobile1 in mine.

If you just want to drain and fill, that is a very simple task. Drain screw at bottom of differential, drain fluid & replace. Fill plug on back cover.

BTW no additives at all. Do not add any!

425EXPEDITION · May 30, 2002

i recently read another post where someone said it had to be done around 5,000 miles ?? i read the service(owners) manual and the first service isnt until 7500 miles and it doesnt call for differential fluid change..am i missing something ?? i read thru the manual and found that even up to 100,00 miles it doesnt call for fluid change..where are you guys getting this info and what doesn it call for intervals of differential fluid chang ?? a buddy of mine is a truck mechanic for local power co. and he said on the fleet(HD2500) trucks with synthetic gear oil they dont change it asits nto called for..thanks

Shaners · May 30, 2002

My '00 1500 Silverado called for the early rear diff. fluid change. I think the '01 and '02 trucks don't require the rear diff fluid to be changed except for severe-duty applications. I know my '01 HD doesn't call for the 5K mile fluid change.

MR. DRAG SLEDDER · May 30, 2002

I did mine @ 500 miles of towing and added Mobil1. When is the next service required? :ehh:

MakoMike · May 31, 2002

What flavor Mobil 1 are you two using?

JimDandy · June 2, 2002

Mobil1 Synthetic Gear lubricant its 75W-90 weight, and meets GM's API GL-5 requirement. Not to mention it's 1/4 the cost of GM's grape scented fluid.

MR. DRAG SLEDDER · June 3, 2002

same as Jim

MakoMike · June 3, 2002

Thanks for your posts. I think I will be changing over the front and rear on mine as I bought the truck used with 14,600mi on it and I am unable to find any history for it, or do you not think I should worry about the front end?

MR. DRAG SLEDDER · June 4, 2002

for what it costs, it's cheap insurance and peace of mind. I would do both at the same time.

pointhalifax · June 7, 2002

Thanks a million guys for your advice and help.

Appreciate having you guys around

Ron PointHalifax

Maxed Out! · June 10, 2002

Note: If you plan on doing heavy sustained towing, the recommended rear gear oil weight is 80W 140. Synthetic of course.

SilveradoWV · June 10, 2002

I dont have the Locker, but on my window sticker it says it has Synthetic gear oil! Is that GM stuff or just an aftermarket brand? Also is it synthetic in the front too?