Diff Oil

[MikeG71]

Morning everyone, Since my front pinion is leaking I figured I would change the oil in my rear diff as well. I have 2 quick questions (1 is a dumb one) concerning diff oil change.

Dumb question first.... Since there is no drain plug will I need to replace the gasket on the rear diff after cracking the bolts to drain it? (I have a good feeling I know the answer, lol)

I bought Lucas 75W-90, do I need to add the LS Additive to that?


I never heard of adding an Additive before (still learning these trucks), but I did see it mentioned in another post. I’m thinking the Lucas has the lubricating properties needed........ ? I just don’t want to go through changing it and find out after the fact otherwise.

Thanks in advance!

 

[moezer]

Dont reuse it use rtv sealant.

If u have a limited slip in the rear then yes u do

Sent from my SM-N950W using Tapatalk

 

[jmd4100]

Morning everyone, Since my front pinion is leaking I figured I would change the oil in my rear diff as well. I have 2 quick questions (1 is a dumb one) concerning diff oil change.

Dumb question first.... Since there is no drain plug will I need to replace the gasket on the rear diff after cracking the bolts to drain it? (I have a good feeling I know the answer, lol)

I bought Lucas 75W-90, do I need to add the LS Additive to that?
View attachment 209387

I never heard of adding an Additive before (still learning these trucks), but I did see it mentioned in another post. I’m thinking the Lucas has the lubricating properties needed........ ? I just don’t want to go through changing it and find out after the fact otherwise.

Thanks in advance!

In the front dif use 75w-90 oil without any additive. In the rear use 75w-140 with an additive. I used a copper sealant on the cover after using a razor blade and carburetor cleaner (brake parts cleaner works too) to get the old sealant off the diff pumpkin and cover. Each takes a little more than 2 quarts, so but 3 of each. Only use additive in the rear if the one you buy doesn't already have it included. If the one you put in the front diff already has an additive it is still OK to use even if you don't have a LSD (anti-spin) in the front. Good luck

Sent from my SM-N975U1 using Tapatalk

 

[dexter]

Check your manual. you most likely don't need an additive.

I've used Lucas; fine.

You don't need to open the diff. You can suck it out with a syringe type of pump and plastic tubes.

 

[Brando_SLT]

If you have the limited slip you will need the MOPAR additive. Otherwise, just use the Lucas gear oil.

 

[MikeG71]

I’m sure it has Limited Slip (2500, 4wd) so is it just 1 bottle of the additive that gets added?

@dexter Thanks for mentioning the pump, I didn’t think about that.

Thank you for the input.

 

[Travelin Ram]

Read your manual. AFAIK HD trucks only use the helical gear type LSD that does not require additive.

 

[dexter]

I’m sure it has Limited Slip (2500, 4wd) so is it just 1 bottle of the additive that gets added?

@dexter Thanks for mentioning the pump, I didn’t think about that.

Thank you for the input.

See answer above.

You need 2 sizes of tubes - large one goes on the pump, smaller one goes into that to make it easier to get to the bottom of the diff.

shove the smaller one into the larger one until it is tight - so it doesn't fall off.

 

[MikeG71]

Thanks again for the help my dudes!

 

[Rambo14]

Pretty sure the manual specifies that no additive is needed.