This product states that is has posi/limited slip lube all ready in it. Should I still use GM posi lube along with the 1.7 Qt is calls for? The rearend is a 3.70 posi 9 bolt.

 

the 9 bolts have a different type of limited slip, i dont think they need additive.....but all that royal purple stuff is gonna do is cost alot of money. if you need additive just buy regular or synthetic gear lube and put it in.

 

No you're fine. Royal Purple is the best!

 

I'm running RP in my new rear. I went to a Torsen though so I have gears now instead of clutches so I just used the RP fluid and no GM additive and it's so quiet you hardly know it's there

If you have a 10-bolt with the clutch type system, you should add the GM additive on top of the RP anyway even though the bottle says it's added that was my experience anyway...

 

Royal Purple is worth every penny... I wouldnt use it in my engine, cause of the cost, but both my trans and rear have it... My rear end gear wine is gone from the richmonds, my tranny NEVER overheats and thats with the stock cooler running, and me getting on it all the time..... I put there gear oil in my gf's eclipse cause its a 5spd and the shifter is like cutting butter, lol its gr8 stuff I highly recommend it..... One of these days ill try that Amisol stuff, but I get the RP at a discount from work so hey why not go with it... And the only reason I tried it is because I was reading gr8 reviews about it... So if u wanna get a fluid u dont need to worry about and your hard on your car go for it.....:hail:

 

i got royal purple in my 9 bolt, i added the posi additive before i read the bottle. works fine.

 

Next to the best, actually...

Certainly better than the typical petroleum-based lube.