Diff fluid conclusions (Royal Purple did NOT do so well)

[99MPower]

Well, after a recent thread on M3F about RP 75w90 and 75w140/85w140, some links have appeared.

I thought RP and the coincidence of blown up diffs in the E36 were just that, a coincidence. After being shown some links of some tests, I will be removing ALL Royal Purple from my cars, and NOT recommending it anymore to my friends

http://www.amsoil.com/lit/g2457.pdf

Thoughts and comments appreciated

M3F thread
http://www.m3forum.net/m3forum/showthread.php?t=327137

[kenndoggy]

I'm still trying to figure out why people wont just run Redline (or OEM) fluid and call it a day. Its proven that it works. What more do you want?

[nsr13196]

Switch to AMSOIL!

[spedhere]

Key take-away: Mobil1 performs well, is affordable, is available but does not do much viral marketing on BF

[ScotcH]

Hmmmm ... a link to a paper on Amsoil's site saying that RP is bad? Say it ain't so

We've been using RP in our tranny and diff for 3 years now ... have yet to blow up a diff. Redline is WAY notchier in the tranny. The OE Castrol M3 diff fluid works very well also. For engine oil, I'll stock to Castrol TWS or Amsoil 2000 20w50

Stop reading shit and go with what people actually use ... or do your own testing.

[Brent 930]

Seems unlikely but anything is possible. While I have yet to run RP in my diff I just recently switched to RP Synchromax for my trans fluid.

Subscribed

[scottbm3]

Use what BMW uses. Castrol SAF-XJ 75w140. Works great and holds up very well especially in my OS Giken diff. A lot of the diff builders recommend it.




-Scott B.

[RacerX]

I use what my diff builder says is good to use, seems reasonable, why make it complicated?

Cheers.

[jbrannon7]

Well, after a recent thread on M3F about RP 75w90 and 75w140/85w140, some links have appeared.

I thought RP and the coincidence of blown up diffs in the E36 were just that, a coincidence. After being shown some links of some tests, I will be removing ALL Royal Purple from my cars, and NOT recommending it anymore to my friends

http://www.amsoil.com/lit/g2457.pdf

Thoughts and comments appreciated

M3F thread
http://www.m3forum.net/m3forum/showthread.php?t=327137

I read thru the M3F thread you linked and it is all hear say, not a single first hand report of RP causing diff failures. The one hear say failure that happened "right after he put RP in it" has no description of the failure.

Facts please, photos would be great, besides amsoils sales brochure.

Joe

[vdshenoy]

My buddy ran Royal Purple Race oil in his FP car's motor at nationals 2 years back and blew his motor - we told him not to change oils on the night before, but he did anyway, and I guess the lower viscosity of the oil caused something to happen...

I stopped trusting their "race" versions after that, and just run either BMW Synths or Castrol or Mobil1 Synths.

[mtrsprt]

Use what BMW uses. Castrol SAF-XJ 75w140. Works great and holds up very well especially in my OS Giken diff. A lot of the diff builders recommend it.




-Scott B.

Agreed! This is the way to go.

[POPS M3]

I use what my diff builder says is good to use, seems reasonable, why make it complicated?

Cheers.

+1

Ken

[M3amazesme]

Hmmmm ... a link to a paper on Amsoil's site saying that RP is bad? Say it ain't so

+1 imagine that.

If the results of their tests was true my diff would have been shattered quite awhile ago.

[cmargosi]

Regardless of where this came from, it's not like Amsoil bagged on all the competition, just a few fluids were shown to fail.

I run the Amsoil and I like it. Do you guys run Gear Lube / Diff Fluid in for your transmissions as well? If not, what do you like?

[99MPower]

I'm not saying Amsoil is the best, as Amsoil obviously did the testing. Facts are facts, (unless Amsoil just completely lied about the entire test) and RP is not as good as the others...

[savage217]

I think the RP Synchromax tranny fluid is awesome. Definitely better then the Redline tranny fluid from my own personal experience. I had Redline in the diff last season and put RP in this season. Haven't noticed any difference in noise, or any noticeable problems at all. RP is a good company and seems to make good fluids. Be advised because their 5-40 is not as good as the 5-30 , 10-40, 20-50. I believe a lot of oil companies have flaws such as this. Mobil 1's 5w-30 is actually not even up to par to BMW's standards, however their 15-50 euro race blend is an amazing oil and has been proven to withstand track abuse by many people. Moral of the story, make sure you buy the right product for the application. Just because the brand name is good doesn't meant the product itself is right for your application. I am not saying the OP's story is true, in fact it seems too biased and ridiculous to take seriously.

[99MPower]

what OP??? hopefully you are not talking about me. I simply came across some information, and was passing it on.

I've always been a supporter of RP. I've personally have never had any problems with it, but I have seen all the threads about "blown diffs, RP in diff". The link to the amsoil test was what changed my mind.

[mcclaskz]

What do you recommend for tranny fluid? I have had 2 getrags that leak the stock ATF fluid under heavy braking on my clutch. I have replaced the front input shaft seal in both applications. Both had loose or wobbly input shafts, but I am thinking of going with a higher viscosity tranny oil as well. What else it used successfully? This is a stock getrag tranny on a ITR E36.

[jbrannon7]

After reading thru the Amsoil report, it appears the best value, most easily obtained gear oil is the Mobil One oil.

Yeah I know, you get what you pay for, sometimes. High volume and good distribution sources like Walmart can give you a good product like Mobile One at a low price.

Personally I have been running RP for 4 years without issue, I will probably switch to Mobile One after reading that report.

I have blown several differentials in previous cars but none were due to oil, all were due to to much horespower for the diff.

Joe

[99MPower]

Personally I have been running RP for 4 years without issue, I will probably switch to Mobile One after reading that report.

Pretty much EXACTLY my same situation. No issues with RP, but after reading that report, will be switching it up

[bennyfizzle]

The LSD carrier bolt issue is a matter of not BMW not using loctite, none of the bolts n my diff had residual loctite on the threads.

[JClark]

Another fluid x is better than fluid y thread without any non-manufacturer testing proof.

[99MPower]

Another fluid x is better than fluid y thread without any non-manufacturer testing proof.

ive been searching and searching for non-partisan testing for diff fluid, and can't find anything except this test. I wish there was more, but nothing that I'm comn up with.

[das borgen]

ive been searching and searching for non-partisan testing for diff fluid, and can't find anything except this test. I wish there was more, but nothing that I'm comn up with.

you'd be best served scouring PhD candidates doing their doctorates

[ScotcH]

I'm not saying Amsoil is the best, as Amsoil obviously did the testing. Facts are facts, (unless Amsoil just completely lied about the entire test) and RP is not as good as the others...

Of course they didn't lie, but i'm sure they very carefully chose which tests to run to make sure that Amsoil would end up on top. Yeah, -30º viscosity is important I suppose, but certainly not for any high perforamnce vehicle I'd be driving ... much less a race car!

All I know is that RP synchormax is the best tranny oil I've used, and I see no difference between RP maxgear and castrol XJ in my diffs (except price ... that XJ is like feking gold!)