firehawk00

I'm changing my rear dif cover with a mac girdle. I want to replace the fluid with Royal Purple synthetic, thing is the only shop in town that carries it only has 80-140 weight. I need to have my car ready by Friday, so I can't order the 75-90. Do you guys think that's to heavy? What can happen if I use that instead?

95z6spd

iTrader: (1)

Well it might actually be better for your rearend as far as durability is concerned. It is heavier so it wil take a few more horses to turn the thicker oil. You might lose 3-4 rwhp with the heavier weight. But also it should make your rear quieter if it makes noise.

firehawk00

Thanks, hopefully it'll break even.....being that Royal Purple is suppose to give you some hp.

2redgmc

iTrader: (1)

Where in TX are you?

You don't need the 85w140.