Changing differential fluid

As far as service, I recommend following the manufacturer's recommendations locaed in the owner's manual. As far as a how to, it is easy to do. Basically all you need to do is remove the differential cover and the gear lube will drain out. Clean all surfaces and replace the cover with a new gasket and refill.

This guide and video will help you get the job done

https://youtu.be/6F26Kir0OCg

and

https://www.2carpros.com/articles/differential-service

Let me know if you have questions or help doing it.

Joe

My 2006 silverado 4x4 has been making a low humming/ grinding sound while driving. It has sure to been at least 35000 to 40000 miles since it has started. I have changed fluids at 50000 miles and recently changed the front diff fluid due to a milky appearance most likely due to an improper seal when the dealer changed the fluids. The noise is a low deep sound that is always in intervals and always the same. the only time it changes is sometimes it isnt there at all. however, at highway speeds 55- 75 it gets longer in the time the sound is made and the intervals are a but longer. At lower speeds the noise is in shorter intervals and is a shorter 'hum". The noise is made with or without the engine running and also with the transmission in N. Both front hub assemblies have been changed and I put on aftermarket because the stock hubs busted. I know its not those bearings. what could this be? Please help.

Was the sound there prior to seeing the white foam in the front differential? Is that the area where the sound is coming from?

No, in fact the sound began before that. I changed the transfer case fluid today and still the same. All fluids have been changed. I suspect it must be the front diff, rear diff, or thansmission areas. But i can feel it in the steering ever so slightly so i must be in the front right?

Since you can feel it in the steering and that is where the oil was contaminated, my first guess is a bearing in that area. Check pinion bearing, axle bearings...

My truck has about 170,000 miles and the transfer case and differential fluid has never been changed. If I change them now can it cause any harm? Also, what kind of fluid goes in the two?

Hello, I'm Danny.

Changing with that mileage will not cause any harm.The most crucial is always an automatic transmission.Here is a tutorial showing how to change the differential fluid:

https://www.2carpros.com/articles/differential-service

I've attached pictures below showing what types of fluid and the capacities for the front differential,rear differential, and transfer case.Hope this helps and thanks for using 2CarPros.

Just want to make sure I am getting the right stuff and amounts

for the front differential i need use 80w-90(how many quarts) and for the rear differential i need use 75w-90 synthetic(how many quarts) and for the transfer case I need to use auto trak II(2 quarts)

Can I use 75w-90 synthetic in both the front and rear? If I have to use 80w-90 for the front differential does it matter if ti says limited slip on the bottle? and for the transfer case if I can not find the auto trak II fluid can I use something else?

so what i was thinking to use, which is offered at my local parts house is:

Valvoline 80W-90 High Performance Conventional Gear Oil for the front differential
Valvoline SynPower 75W-90 Full Synthetic Gear Oil for the rear differential
Valvoline Transfer Case Fluid for the transfer case

also, I have seen a couple different recommendations o how to fill them all. Some say to fill all of them until oil starts to come out of the fill plug and others say that for the differentials to fill about 1/2 inch from the fill plug????? which way is right?

Hello again.

If you want to give me the VIN number (vehicle identification number) I can find out if your truck came with limited slip differentials and what size differentials it came with.I can then provide you with regular non-Chevrolet dealership regular auto part store brand fluids and capacities.Hope this helps and thanks again for using 2CarPros.

Danny-

2GCEK19N531361849.

Hello again.

Okay, I'll have the info for you in the morning.Thanks again for using 2CarPros.

Danny-

Hello again.

As far as the transfer case goes it shows to only use the GM brand fluid which for whatever reason is called manual transmission fluid and calls for 2.1 liters. Both the front and rear differentials call for 75-90 weight limited slip gear oil.The front holds 2.0 qts and the rear holds 3.0 qts.You can use any brand for that.Hope this helps and thanks again for using 2CarPros.

Danny-

Sounds great and thank you!

Since you looked it up what size differentials does it have?

Thank you once again, you guys rock!

Hello again.

The differentials are 8.5 size with 4.10 gear ratios. Hope this helps and thanks again for using 2CarPros. Hope you will use us again in the future.

Danny-

When filling I just fill until a little comes out of the fill hole, right?

Hello again.

Yes! On the differentials and the transfer case. Thanks again for using 2CarPros.

Danny-

how do I do it?

remove the cover off the rear diff to drain the fluid. There is a fill plug on the front of the diff housing. It will be on the pass side.
The front diff will have a drain plug on the driver side, and a fill plug just above that.
You should use full synthetic gear oil in both diffs.

thanks

don't forget to leave feedback :D

want to check and change the front differential fluid but was unsure how to do it...

raise vehicle and support. place drain pan below differential cover. loosen but DO NOT remove differential cover bolts. break cover loose. allow lubricant to drain. finish removing bolts and clean pan. reinstall pan then fill with 80W or 80W-90 GL-5 gear lubricant to within 1/4" (6mm) below edge of the filler hole. If you have the limited-slip or locing differential then also add 4 ounces of limited slip additive.