Royal purple
Logistics Pro
Joined: May 2011
Posts: 4,832
Likes: 668
From: Maine
Personally, I think RP is junk.
All tests I have seen RP was one of the worst synthetics, it didn't hold it's viscosity at all. Ok for short life.... but the longer you use it the thinner it got.
All tests I have seen RP was one of the worst synthetics, it didn't hold it's viscosity at all. Ok for short life.... but the longer you use it the thinner it got.
Senior User
Joined: Sep 2008
Posts: 419
Likes: 0
From: Alfred NY and Long Island
I was looking into the Royal Purple Synchromax to put in my 6 speed. Maybe I won't though. I have a friend who swears by Amsoil, and he can get me a pretty good deal through his business. So maybe I will stay away from the RP and go with Amsoil.
O BTW I put Mobil 1 synthetic in my rear diff and so far so good, I think I paid like 14 a qt though.
Dennis
O BTW I put Mobil 1 synthetic in my rear diff and so far so good, I think I paid like 14 a qt though.
Dennis
Postmaster
Joined: Sep 2007
Posts: 4,005
Likes: 3
From: Mcafee, NJ
I was looking into the Royal Purple Synchromax to put in my 6 speed. Maybe I won't though. I have a friend who swears by Amsoil, and he can get me a pretty good deal through his business. So maybe I will stay away from the RP and go with Amsoil.
O BTW I put Mobil 1 synthetic in my rear diff and so far so good, I think I paid like 14 a qt though.
Dennis
O BTW I put Mobil 1 synthetic in my rear diff and so far so good, I think I paid like 14 a qt though.
Dennis
hard to believe but it takes ATF
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Senior User
Joined: Sep 2008
Posts: 419
Likes: 0
From: Alfred NY and Long Island
Ya I read that it takes the Auto Tranny Fluid. The RP web site said that the fluid is designed specifically for manual trannys that are designed to take ATF. Thats why it caught my mind.
Any other recommendations for fluid in the zf6?
Thanks
Dennis
Any other recommendations for fluid in the zf6?
Thanks
Dennis
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Lead Driver
Joined: Jun 2003
Posts: 8,298
Likes: 24
From: Damon (South East Texas)
My friend has a water well service uses his trucks to haul and tow loads constantly. Everything that had the RP in the diffs have had failures and the oil turned into a black stinky mess. I have the Mobil syn in my diff and trans. Soon to be in transfer case also.
still plays with trucks
Joined: Mar 2004
Posts: 1,743
Likes: 3
From: Twin Falls Idaho
I've had RP in my diff for 50K and it still looks nice and purple. Course I don't tow much
. only about 30,000 miles a year! I also have it in my tranny and t/case. I've had good luck with it.
as always, your mileage may vary!
Barney
. only about 30,000 miles a year! I also have it in my tranny and t/case. I've had good luck with it. as always, your mileage may vary!
Barney
Logistics Pro
Joined: Aug 2005
Posts: 3,884
Likes: 180
From: Morgan Hill, CA
Mobil 1 Syn ATF gets my vote. I had some smuggled across state lines recently since you can't find it in CA very easily.
Posting Guru
Joined: Jun 2008
Posts: 1,037
Likes: 0
From: Albuquerque
Ran it in my harley, once. Changed out the dino for synthetic burple. 250 miles later, lost the rear cylinder due to overheating. Back to running Penzoil 50 weight and no issues.
Not going in my truck. Just sayin.
Not going in my truck. Just sayin.
Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
Back to the O/P:
I like Mobil-1 75W-140 in both the front and rear differentials. Good stuff, and available most everywhere.
Also, I did not need to add any friction modifier to get the rear clutches to perform correctly, but YMMV.
If you have a SRW, synthetic is an absolute MUST! You might be surprised at what the temperatures get up to in there.
Pop
I like Mobil-1 75W-140 in both the front and rear differentials. Good stuff, and available most everywhere.
Also, I did not need to add any friction modifier to get the rear clutches to perform correctly, but YMMV.
If you have a SRW, synthetic is an absolute MUST! You might be surprised at what the temperatures get up to in there.
Pop