Community Forums

ualdriver · 08-29-2020, 08:02 AM

Hello-

I'm pretty sure my 2013 Freightliner XCS has a Axle Alliance Company R17 5-2N rear differential. It's due for an oil change, and it says to use 75W90 oil. When I look online, I see two different types of 75W90 oil when I look at Mobil 1. One says Mobil 1 75W90 LS. The other says Mobil Delvac 1 gear oil. Which one do I use? The Delvac is cheaper as it comes in bulk.

Thanks!

R.Wold · 08-29-2020, 08:58 AM

LS is limited slip with additives for the clutches in an LS differential. I have yet to see a motor home with a LS differential, but there should be a sheet metal tag on the diff mounted with cover bolts and it will have the exact model number that you can use to be sure.

Unplanned Tourist · 08-29-2020, 09:11 AM

Just be sure you get EP (extream pressure) rated oil.

You will destroy your diff in a hurry if it's not EP oil.

Happy Glamping.

ualdriver · 08-29-2020, 10:35 AM

How do I know if oil is rated for extreme pressure?

So I can use any type of oil, as long as it is 75w90?

R.Wold · 08-29-2020, 12:43 PM

mobile one synthetic is fine

Unplanned Tourist · 08-29-2020, 05:22 PM

Quote:

Originally Posted by ualdriver

How do I know if oil is rated for extreme pressure?

So I can use any type of oil, as long as it is 75w90?

It will have “EP” somewhere on the container.

Unplanned Tourist · 08-29-2020, 05:31 PM

Quote:

Originally Posted by Unplanned

It will have “EP” somewhere on the container.

Or a “GL-5” rating.

R.Wold · 08-29-2020, 05:50 PM

Mobil One is rated GL-5 amoung many other ratings and is approved for about every heavy duty manufacturer.

https://www.mobil.com/en-US/Commerci...Gear-Oil-75W90

ualdriver · 08-29-2020, 09:17 PM

All through R. Wold-

Thanks very much. I'm going to buy a couple of gallons of Mobil Delvac 1 75w90 and use that. I found it for $33/gallon + $11 shipping for a total of $77 for the two gallons. I think that's a good price?

dp7 · 08-30-2020, 12:05 AM

Quote:

Originally Posted by ualdriver

Hello-

I'm pretty sure my 2013 Freightliner XCS has a Axle Alliance Company R17 5-2N rear differential. It's due for an oil change, and it says to use 75W90 oil. When I look online, I see two different types of 75W90 oil when I look at Mobil 1. One says Mobil 1 75W90 LS. The other says Mobil Delvac 1 gear oil. Which one do I use? The Delvac is cheaper as it comes in bulk.

Thanks!

Pages from Freightliner workshop manual (attached) call for Delvac 1.

Mobil 1 LS is for passenger cars & light trucks with limited slip differentials.

ualdriver · 08-30-2020, 12:07 AM

Quote:

Originally Posted by dp7

Pages from Freightliner workshop manual (attached) call for Delvac 1.

Mobil 1 LS is for passenger cars & light trucks with limited slip differentials.

Thanks DP7!

R.Wold · 08-30-2020, 12:29 AM

Quote:

Originally Posted by ualdriver

All through R. Wold-

Thanks very much. I'm going to buy a couple of gallons of Mobil Delvac 1 75w90 and use that. I found it for $33/gallon + $11 shipping for a total of $77 for the two gallons. I think that's a good price?

I always shop Napa so that’s my price comparison. I’m sure you can beat their price with Amazon, but I like walking in to the local auto parts store and doing a little impulse buying too, but yes, I think that’s about as good as you can do.

R.Wold · 08-30-2020, 12:36 AM

Amazon price looks like $50/gal. Where are you getting it for $33? Summit has it for $36

vettenuts · 08-30-2020, 06:22 AM

I think if you get the information from the differential manufacturer, you can find an oil that meets the specifications (I think you will find you have a Detroit differential). I just used the Delvac in my Detroit (Mercedes Benz) differential in my 2015 Tiffin because it was on their approved lubricant list, which is documented online. I don’t think you will find Mobil-1, available at places like Autozone, on any of the manufacturer approved list (Detroit, Meritor, etc.).

As a side note, best shipped price by far for the Delvac was Summit Racing.