What gear oil to use

[john3976]

Simple as possible and not worrying about warranty issues means only one thing. Use the Stock oil. Buy it from the parts department at your local dealer and save your recept... it doesnt get any simpler then that and you know the original oil works fine with no shudder.

Any brand GL5 rated oil of the correct weight and type can be used. If you use the wrong oil i. e. GL4 instead of GL5 and you break the rear end then you will pay for it and not DC.



As for the above engine warranty being denied, if he was using extended drains and broke his engine then they have the right to void that warranty, if he used an API certified oil speced for diesels and followed the recommended drains then they cannot void his warranty, unless he was using Amsoil in which case it's not being API certified they could void the warranty.

 

[Diesel Power]

if i were you i would try amsoil, there 30+ year reputation speakes for it self. thanks Oo.

 

[Ken55]

I tried Amsoil severe gear 75w90 at 30000 miles on the truck. After about 25000 miles I started to get the shudder in my rear axle. I dumped it and put in Mobil 1 syn and the shudder went away. Don't know why it started but it did. Also fluid was really dirty when I changed it!!!

 

[Bartlett]

Ok i am going to try one of the above mentioned fluids and see what happens. Have to get that shudder to go away before pulling the 5th wheel.

mike

 

[Edgemann55]

Just replaced F&R diffs with PML covers and Amsoil severe gear 75-90. No shudder at all. Nice thing is now my next change is just drain and fill. Got 50,000 mis till that happens. Amsoil in everything.

 

[Bartlett]

I drained the texaco syn-star 75-90 and put in royal purple 75-140 and presto... . the shudder is gone. Also got valvoline atf +4 at napa for 3. 90 a quart and did a transmission service. All seems well now.

 

[sevobuck]

I thought the Royal Purple has additive in it?

 

[Bartlett]

yes it says that it has it.