What type of oil do yall run in your diffs. What do recomend? I am doing a compleate seal replacement in front and back diffs and just wondered what the best oil to use is.

 

I'm running 75w90 full synthetic in my diff, .... maybe not penny-wise but I had to rebuild my orig diff and it was a real pain, ... good deal for me to pay the extra pennies, ....

 

Same here, Amsoil.

 

Amsoil 75-90, may try Amsoil's severe gear next change, I do lot of towing. No issues yet though.

 

Plain old 85W-140 or somesuch, either said Valvoline or Rotella on the bottles.

Be sure to add the limited-slip stuff if it applies to your situation.

 

75-90 redline

 

could i run strait lucas oil and is 2 quarts really all it holds

 

I wouldn't mess around... put real gear oil in there. 75W90 or so if it's a regular work truck, 75W140 if you tow. Mobil makes a synthetic that says "LS" on it for Limited Slip, so it has the additive already in it. If you have an open diff, don't bother with the LS additive.

After that... it's all brand preference. I want to say the rear end holds closer to 4 quarts and the front around 3 if I remember correct....

Don't even bother buying gaskets for the pumpkin cover. Both my surfaces were pristine, and they still leak like a sieve. Use some RTV for your gasket, and only finger tighten your bolts and allow the RTV to set. Then, the next morning you can ease them up with a ratchet when the RTV is dry.

EDIT:From the sticky: D70 rear = 7 pints (3.5 qt) and D60 front = 6.5 pints (3.25 qt)

Fluid capacities:
https://www.dieseltruckresource.com/d...d.php?t=204044

 

I run royal purple 75/140. I get it real real cheap, thats my reason. Before I was running gm 75/90 full synthetic for the same reason as above! Both have and are working real good for me. Not sure on the price if you buy it at the counter. I think the royal purple is cheaper than the GM stuff?

 

Same here^ I use RP and so far so good. Please everyone knock on wood!

 

I too am using Amsoil 75W90 and have been for quite a few years. If you tow quite a lot 75W140 is a good choice. What I found out about 75W140 using oil analysis was that 75W140 retains all too much water unless you tow enough. It does not heat up enough under moderate towing and daily driving to burn off water and temperature sensitive comtaminents.

Bob

 

Mobil 1 75W150 LS in the rear, 75W90 LS in the front.

 

Where did you purchase your Mobil 75-150 Synthetic LS oil? How costly is it? Thanks, John

 

I just got some of the Mobil 1 75-90 LS to do a fluid change and was wondering if the amount of additive already mixed with the fluid enough, or will I need to add some of the Mopar stuff as well?