I'm putting a Poison Spyder cover on the kid's rear Dana 44, and I'm curious to know which gear oil to use.
I'm not sure if this axle has LSD, so I'm going to use synthetic oil, just in case.
The numbers are confusing, and I think I need 75-140 oil, as this vehicle has 4:11 gear ratio.
Am I correct?

Thank you for sharing your knowledge.

 

Yes, I believe that's correct. I put the same covers on mine (which has a LSD in the back, and 3.73 gears) and that's what I used.

 

4.10 would be your gearing. I've always ran 75-90w in mine until last night I switched to 140w because of adding an Aussie and trying to quiet it down.

 

i used 75w90 in mine 1.5 in the front 2.5 in the back i belive.

 

SAE 80W-90 (API GL-5) or equivalent.
For trailer towing, use MOPAR Synthetic Gear & Axle Lubricant SAE 75W-140 or equivalent.

If the new cover is bigger than the OEM cover, you will need to have more oil in the differential.

The oil fill plug on the new cover may be higher than the OEM plug. Filling to that level would be way too much oil.
Make sure the oil level is a little above the bottom inside of the axle tube so oil will flow out to the end bearings.
A bent zip tie makes a good dip stick.

 

I use 80W-90 in mine front and rear. Most 80W-90 comes with the LSD additive already in it, so just check the bottle. That's good advice on filling them up. I know my Solid covers hold more fluid than stock, but you should still put the stock amount of fluid back in or you'll be blowing lube out of your breather tube. If I remember my numbers correctly, the front Dana 30 holds 1 quart and the rear Dana 44 holds 2.5 quarts.

 

I don't quite understand your thinking.
If your Solid covers hold more oil, the stock amount of oil will be at a lower level in the housing. It's important the oil is at the correct level so oil will be able to lubricate the outer axle bearings.

Am I misunderstanding your post?

 

I think we're sorta saying the same thing. LOL In other words, don't fill it to the bottom of the fill hole with aftermarket covers.

 

Would suggest using lube locker gaskets if replacing cover as they are more forgiving if knocked on rocks at not leaking afterwards.

 

I wonder how many folks apply the traditional RTV gasket maker properly? I suspect this to be the source of the problem with some folks having leaky differential covers.

Apply a bead that is 1/4" to one surface and then mount the differential cover immediately. Finger tighten the bolts. Wait one hour for the gasket maker to set. Tighten to torque specifications (I think it's 30 ft lbs). Takes 24 hours to cure but you can put oil back in after torqued to spec.