Rear end oil?

[ArkansasMystic]

I'm gonna change the oil in the rear end on my car. It's got 135k miles and I don't know how long it's been so I'm sure it would help out. I've got a couple questions first. What weight oil is needed? How many quarts? What oil should I use. I know I'm suppose to add friction modifier, does it really matter what kind? Any suggestions? Thanks!

 

[C O 13 R A]

TTT for ya! I'm looking to do the same would like the same info.

 

[BMF42]

I used 75w90 royal purple. Its worked great with no issues. With RP you don't need friction modifier, but if you really want it check out ebay. I got my friction modifier for really cheap on ebay. Good luck.

Al

 

[gq916]

i took it to a shop and they used 3 quarts 75w-90 valvoline(non sythetic) plus additive.

if you go with sythetic use redline 75w-90 plus additive seperate

 

[19Mystic96]

i have 75w-140 from Redline + friction modifier.. around 3 qts.. just pour until it starts coming out the fill hole..

 

[ArkansasMystic]

I'm thinking I'm gonna shell out money for the RP. I really need it changed this week, and the local parts store apparently doesn't have friction modifier (they had some type of additive they were trying to sell, but it wasn't friction modifier).

 

[Tabres]

I used 75w90 royal purple. Its worked great with no issues.

This is what I used, plus a bottle of friction modifier which I had to purchase from the dealer and also happens to be the foulest smelling stuff I have ran across in quite a while.

 

[FoxFour]

From Royal Purple's Site
All viscosities of Max-Gear are formulated with hypoid friction modifiers necessary for use in clutch or cone type differentials. No additional additives are necessary.

 

[ArkansasMystic]

That's the benefit I'm looking at. I really need to get the oil changed this week. I can't get the friction modifier locally, but can get the RP gear oil. Hate to spend $60, but I think it'll end up being money well spent.

 

[ARdoller]

my rear only used two of the 3 quarts of RP gear oil that were included with my gears.

if you can, id change the gears/oil in a very well ventilated area. used gear oil reeks. it tends to give me headaches.

 

[nckissfan]

I used Lucas rear end oil. I added a friction modifier.

 

[ArkansasMystic]

I guess what I need to verify is that I don't need to add the friction modifier. I've got some slight noise coming from the rear which I've been told is just because the fluid needs to be changed and the friction modifier added. I know the RP site says it isn't needed, so I guess I should take their word for it. Any thoughts on this?

 

[CleanNGreen96]

I usually go with the Heavy Duty Lucas Synthetic 80-90w GL-5. It says it already has the friction modifier in it like alot of aftermarket brands do. But to be on the safe side, I'd just stop by the dealer an buy 4oz of the stuff. It's cheap insurance just to have it, than risk burning out your LSD...

 

[ARdoller]

I guess what I need to verify is that I don't need to add the friction modifier. I've got some slight noise coming from the rear which I've been told is just because the fluid needs to be changed and the friction modifier added. I know the RP site says it isn't needed, so I guess I should take their word for it. Any thoughts on this?

do you have aftermarket gears? if theyre whining, its more likely that they were installed incorrectly. not saying they wont work right, but if theyre not set correctly, they will whine. this is apparent with most Motive gears (vs FRPP gears that i hardly ever hear anyone complain about whining. mine are FRPP and they are silent).


if new oil/friction modifier doesnt do it, you may need the gears reinstalled if you want to get rid of the noise.

 

[ArkansasMystic]

I have FRPP 3.73's that have been in for at least 8-9 years. I spoke with a guy that works on rear ends locally and he said just change the fluid and add proper amount of friction modifier and it should be good to go. It's hard to explain, it's really not a whine. We'll change the fluid and go from there. I can get the friction modifier, that's not a problem. I just don't wanna add it if it's not needed.

 

[ARdoller]

i wasnt expecting you to say theyve been installed for 8-9 years...

 

[ArkansasMystic]

Haha, yep. My brother bought the car in 02-03 and they were in then.

 

[GForceJunkie]

With Royal Purple gear lube you do not need to add friction modifier.
I used it after a gear swap and it only took 2 quarts to fill it.
After about a thousand miles, still quiet. I think all of RP's products are worth the money. I don't think it smells that bad.(Not). It's just dead dinosaurs.:burnout:

 

[ARdoller]

With Royal Purple gear lube you do not need to add friction modifier.
I used it after a gear swap and it only took 2 quarts to fill it.

same here, like i mentioned before.

I think all of RP's products are worth the money.

their motor oil is a waste of money. i see them do comparisons on tv all the time between RP and other off-the-shelf products, and RP never lives up to the hype.

plus, most people that use RP in their car, most likely didnt own the car for most its previous life, and a lot of professions seem to say that if a car hasnt been running RP most of its life, that its really not worth starting now.

but thats just what ive heard. i dont have deep pockets to spend on RP, so i dont buy it. their gear oil came in a package deal i got with my gears, so i used it then. but i never hear any complaints about their gear oil.

 

[ArkansasMystic]

I did read one comparison (pretty lengthy) and it didn't rate the RP very high at all.
http://www.synthetic-oil-tech.com/Gear Lube White Paper.pdf
I'll call the dealer tomorrow and make sure they have some friction modifier and I'll probably pick it up depending on price. I just need to decide on what brand of oil to use. I've heard good things on mobile 1. Also, with 135k on the car, should I get synthetic or not? I know with engine oil you don't want to switch to synthetic after that many miles, but wasn't sure on the rear end.