royal purple diff fluid

[nonova0074]

I just service my rear diff with royal purple, if anyone has used this fluid did you add the gm additive. I didn't use it and its quite, I was wonderinf if it should put it in. I also added a ta performance girdled cover.

 

[joemama]

Don't need the additive with Royal Purple.

 

[nonova0074]

Thanks is swear by rp product I put 3 qts in and am thinking about adding another half, the only thing is it isn't cheap at 16 per qt

 

[nonova0074]

Sorry cell phone grammar

 

[turboc87gn]

Talked to several drivetrain guys and every one told me not to use synthetic fluid in the diff!!!!

 

[STP]

I tend to agree...I've always run reg ole 75w90 Valvoline in my diffs with the additive..However, a month or so ago I installed Royal Purple in a friend's diff and it is not as smooth around corners as it should be. I'm draining all the synthetic out and refilling with reg 75w90. For insurance, if I were you I might dump a bottle of additive in it.

 

[turbo nasty]

FWIW a new Eaton posi unit (clutch just like ours) has a wraning label that comes with eth unit that says not to use syn fluid as it will hamper the clutch operation

 

[joemama]

All that may be true, but I've had Royal Purple in my differential for six plus years. It actually quieted up a whine in my differential on full lock turns and U-turns. G80 posi.

 

[turbo nasty]

All that may be true, but I've had Royal Purple in my differential for six plus years. It actually quieted up a whine in my differential on full lock turns and U-turns. G80 posi.

But is your posi working correctly? Just because its quite doesnt mean that its alowing the carbon friction disks to grab and properly distribute the power to both wheels as the LSD is designed to do. There is a reason they have that label in there.

 

[joemama]

Have not calculated if both wheels are equally putting out the same power. If I was worried about that, the car would have a spool.
All I know is both tires go up in smoke instantaneously:biggrin:

 

[we4Mateo]

I've used Mobil 1 and RP rear end fluid, I needed additive to quiet them both up. Both wheels spin evenly, evn with additive and synthetic fluid, according to the black marks

 

[Steve]

I have always used regular 75w-90 with the additive also. I know Eaton and Auburn both recommend against synthetic gear lube with thier carriers. The posi's require some friction to work properly and I can't see spending more to go against the manufacturers recommendations. And besides I have never seen a rear that was damaged due to lubrication issues unless it just did not have any lube in it!

 

[turbo nasty]

I have always used regular 75w-90 with the additive also. I know Eaton and Auburn both recommend against synthetic gear lube with thier carriers. The posi's require some friction to work properly and I can't see spending more to go against the manufacturers recommendations. And besides I have never seen a rear that was damaged due to lubrication issues unless it just did not have any lube in it!

DING DING DING we have a winner...can I get a AMEN:biggrin: