Charlie, just don't know if/how your truck is different than mine. Are you saying you have no owner's manual with your truck, or it just isn't available to you for some reason? I know that mine calls for 75w-140 synthetic in the back, with additive if you have limited slip, and GL-5 75w-90 in the front.

I have to agree with you about the parts store clerks. Trust them I don't, but I know them well enough that they let me look over their shoulders when they look stuff up for me on their computer. Sounds like yours is similar to mine, as well, as far as never having everything you need in stock. I'm sitting here trying to order what I need off of their website, but it doesn't appear they will ship any fluids. So, I'm stuck finding it elsewhere or have to wait for the store to order it.

 

Yeah I'm at the store's mercy getting fluids here in deliveranceville.

Do you think 75-90 with LS additive will work for a few days? Im thinking that a few days of running it then swapping it for 75-140 will clean it up pretty good.

 

I dont have the expertise to answer that. I assume it might be okay in a pinch. But i would try not to have to do that service twice in a short period if i could.

 

manual says 75-90 for non towing and 75-140 for towing. you will be fine. Takes almost 3 qrts and i used LSD friction modifier in mine and used 3oz per 1 qrt of oil

 

My manual calls for 4 oz. of additive for LSD. Funny, it tells me how much additive to use but I can't find anywhere that it tells me how much oil to use. I realize the rule of thumb is to fill the bottom of the drain hole but it would be nice to know approx how much oil to have on hand to do that.

 

In the 04 Srv Man thats avail in the links in my sig, start on page 18 and it covers everything

 

75w-90 will be fine unless you are hauling/towing heavy. But I'd probably change it a bit sooner than if I was running 75w-140.

Take you a good gander at the fluid, the ring & pinion and the magnet for those clips or metal fragments. These factory LSDs can cause BIG problems if left unchecked...

 

i just did mine a couple weeks ago. the bottom of the housing had like 1/8 inch thick layer of metallic-like sludge sitting there, and part of a broken clutch pack retainer. It still works fine though... you'd never know anything was messed up in it. and after I changed the fluid and put the additive in, it quit "moaning" and ratcheting during low speed turns. I used mobil 75-140 and a 4 ounce bottle of mopar additive