ninety4formula

Hey guys I don't have my book with me to tell me what gear lube I should be running in the rear end. I plan on stopping after work to buy some. What are you guys running?

cv67

80w/90 is fine.

Kubs

Remember not all fluids have the limited slip additive in them. Either pick some up with the oil or get a fluid that has additive in it.

I use the AMSOIL Severe Gear 75W-90 in mine which includes the additive. All I did was put the fluid in and have had zero issues with chattering tires.

http://kahunamotorsports.com/svg-product-page.html


If you do add additive, make sure to drive in figure 8s in a parking lot to make sure it mixes in well and gets to the clutches quicker.

Analog Kid

Royal Purple 75w-90. It also has the additive in it. Good stuff.

Nathan Plemons

Mobil 1 is good stuff but I believe you do need to put the additive with it.

pmihaltian

This gear oil works great for me.

1985 Corvette

I'm running into this issue as well with a D44 I'm replacing fluid in soon. It's not rocket science but one tends to make it such when you see all the choices for fluid available.

Local Car Quest parts store has Royal Purple 75W-90 which is listed with additive. Also, the diff requires 1.5 quarts of fluid gear fluid plus additive correct?

Local GM dealer told me one container of gear fluid plus three bottles of slip additive. I did some reading on the forum and see two 23 ounce bottles of GM 80w-90 gear lube and one bottle of slip additive.

Pro/Cons of using Royal Purple 75w-90? 80w-90 is what I see used the most so far.

Kubs

The total fill is 1.8 quarts.

The second number is what is more important. You could put in straight 90 weight oil but it would be much thicker in the cold. I dont think you will notice a difference between 75W or 80W oil.

1985 Corvette

Well, I picked up two quarts of Royal Purple Max-Gear 75W-90 with Synerlec. I'm assuming Synerlec is the slip additive. I won't be filling the D44 today, I just finished cleaning off the surfaces to seal the batwing back to the differential again.

The plan was to lay it flat on the garage floor tomorrow with the drain plug off until Royal Purple comes spilling out during adding. The drain plug has the classic signs of vice grip bite marks all over it.

I'm using high temp red silicone gasket material, same stuff used for oil pans and valve covers.

pmihaltian

I have used Royal Purple gear oil in my Dana 44 differential and my Super T-10 tranny for several years now. I personally spoke to one of the tech specialists at Royal Purple HQ in Texas and he assured me that I did not need the limited slip additive when using Royal Purple gear oil. Sooooo, I did not add anything to the trans or the differential other then the Royal Purple gear oil. I have had no ill effects what so ever. What's more, my transmission shifts much smoother, is significantly quieter and no longer pops out of 2nd gear when decellerating down a hill.

FWIW - my experience has been very positive.

1985 Corvette

That's reassuring. Just buttoned up my D44. Any particular torque rating for fastening the bolts to seal it up? I just did them to 30 ft lbs with a wrench. They feel good and tight The red stuff is squished out all the way around, that's a piece of mind for me so far. I tossed the camber brackets on the corners and fastened those as well for full clamp.

When the drain hole starts to spill fluid leave it at that? I thought about plugging the hole then adding a little extra for good measure. I've always been terrible at the simplest things like sealing and filling.

pmihaltian

Assuming that your Vette is level and not tilted toward the front of back, when the FILL hole starts to spill fluid leave it at that. Do not add just a little more as to over-fill either the trans or the differential, you run the risk of blowing out your seals - AND you don't want to do that.....

kimmer

I use Royal Purple everywhere.