hi guys i have a 04 ram 3500 and planning on chnging differential oil. i wanna make sure am doing this right.
does my car have limited slip hence need to use synthetic or not?

 

It may or may not have LSD, it depends on how it was ordered. You can check for a tag on the axle or a sticker in the glove box.

BUT whether or not it has a LSD doesn't dictate the use of conventional or synthetic lube. It dictates whether a friction modifier should be used. I'd use a full synthetic lube in the rear axle (75w-140) whether it was equipped with a LSD or not...

 

Dodge specifies synthetic for the diff. If there's no sticker on the glove box door, an easy test for LSD is to put one wheel on slippery and one on dry. Goose it (don't punch it). If it moves, it has LSD.

 

You could also get a build sheet from any dodge service department. They match your VIN to the Chrysler database.

 

thanks guys thats really helpful
Hammer
does a full synthetic lube need a friction modifier ?

 

it'll be great if u guys confirm this
does a full synthetic lube need a friction modifier or not ?

 

The need for the modifier and the requirement of synthetic have nothing to do with each other. Some diff fluids contain the modifier, but not because it's synthetic. If you have LSD, you must use the friction modifier. If you don't have LSD, the friction modifier will not be necessary, but it may be in the fluid you use.

Stock LSD? Friction modifier required. No stock LSD? Synthetic required, but modifier not necessary (won't hurt, you just don't need it).

 

^^^ Exactly

 

thanx MikeHTally & weedahoe
would it harm using a conventional oil?

 

Might cause extra wear depending on the oil used.