rear diff fluid!

[Big_T]

hey guys, i need to replace my oil pan gasket and my rear diff gasket. had a question for everyone tho.... what rear diff fluid should i put in when im changing it out? i plan on changing my gears from stock to 3.73's but i cant do it quite yet due to the fact my suspension NEEDS to be replaced and thats a little more urgent than my gears, so im probably going to have to change the fluid again soon anyway, so any suggestions or recommendations on what diff fluid i should use?!

 

[Tony]

i used royal purple with stock and 373 gears. full synthetic cant remember but i think 75/90? gears use to howl just a little and it shut them right up and has for months! good stuff and worth the extra $$. two bottles fill it just fine. no friction modifier needed. limited slip dif already added i'm pretty sure, lol

 

[94RedGt]

If your gears are not making any noise then dont change the fluid in it until you swap gears, anyways i used 80/90 oil with a bottle of friction modiffier.

 

[joekd]

If you have a stock diff cover then two quarts of 75w90 royal purple, one bottle of friction modifier

 

[RichV]

Just ask the guys at the part store, they can look it up. I used the Valvoline Synthetic with LSD modifier in it.

 

[Big_T]

im not changing the oil because its making noise... im changing the gasket because its leaking all over my driveway and that = NO BUENO! so to replace the gasket i need to empty it out. so the verdict is sounding like 2 bottles of 75/90 royal purple with 1 bottle of friction modifier? or can i go with something cheaper for now until i swap out my gears?

 

[OnyxCobra]

I wouldn't waste my money on Royal Purple, just buy regular diff fluid and a bottle of friction modifier. Should do you perfectly fine.

 

[modo]

are you sure its the rear cover and not the pinion seal? fluid is going to get blown all over and it will look like its coming from the rear cover. look near the drive shaft and see if there is oil splatter all over the place. if so its the pinion seal.

 

[Big_T]

no its coming from the rear diff. very small drip but when its sitting in my driveway or at work it makes a little spot. this car was never treated the way it should have been and never had its routine maintenance so seeing as how it has about 137K miles on it i think its time to change the gaskets. im positive its the rear diff gasket and my oil pan gasket.

 

[joekd]

Don't use a gasket on the diff cover, just RTV

 

[backwater309]

Ad:

Don't use a gasket on the diff cover, just RTV

...agreed​

 

[Venom351R]

Some of the synthtic rear end gear oils come with friction modifier already added. Ive used the NAPA brand stuff before and had no issues, Ive used the Mobil 1 and currently have AMSOIL in the rear and engine. Eventually doing a full AMSOIL Fulid change over.