Engine/Transmission (1998.5 - 2002) oil weight questions

[HD-J78]

Hi, wanting to change out all my fluids with synthetics (Amsoil). Owners manual calls for 90w for the rear and 75w for the NV4500. Amsoil's web site says to use 75w-90/80w-90 for the rear and 75w-90 for the NV4500. Should I try to find another brand synthetic or just go with what Amsoil recommends?

Thanks.



2000 2500 4x4 cummins

 

[DIESELWRKS]

I have been happy for the diff, oil running royal purple or redline... I can get redline cheaper than amsoil where I live... I usually run them 25-30k miles. . as far as the nv4500 this transmission if I remember is picky there is only one lube and one only that was a true match and that is the dealer specific for that. I dont know for sure to say if amsoil is a 100% match to the dealer oil. .

 

[AH64ID]

Amsoil SVO 75w-140 is what I would run front/rear.

Looking at the service manual synthetic 75w-140 is the standard lube for the front, and 75w-140 is recommended in the rear for HD applications.

AMSOIL Synthetic Gear Lube - Gear Oil

For the NV4500

AMSOIL Synthetic Automatic and Manual Transmission Fluid

Dodge Ram Fluid capacity and specification Information

 

[SHobbs]

I have been using Royal Purple 75W-90 in the transmission and 75W-140 in the rear end. I believe the 75W-140 is recommended for those that tow regularly or tow heavy, 75W-90 is ok for occasional lite towing. Normal change interval is around every 30k for me.

 

[Mhannink]

changing the oil now on my 97 been running schaffers full syn 80-90 in trans and diffs have had 0 issues for 2 years and i dont know how many miles.

 

[SnoKing]

In Alaska I think I would run the 75w/90. I run 75w/140 in the rear and 75w/90 in the front. I tow a 5th wheel trailer and have the Dana 70(auto).



SNOKING

 

[amsoilman]

If you use what Amsoil recommends, you will have no problems! I sell alot of (SVG) Severe Gear 75W-90 for the differentials, well as the (MTG) Manual transmission 75 W-90 GL-4 fluid for the 4500 transmission.