Blackstone on Royal Purple MaxGear-- How Serious?

[Kayger12]

I ran RP MaxGear (75w90) in my 2005 BMW 330ci differential for 16K miles.

After I read some reports of differential failures after running RP, I decided to switch out to Red Line and send a sample of the RP to Blackstone.

The report looks to be cause for concern, but I do not know very much about this differential as far as the types of metals present, nor what conclusions I can draw from these kinds of numbers (if any).

I know there's a ton of knowledge on this site and appreciate any feedback and/or interpretations.

Thanks for your time.

 

[Loobed]

Originally Posted By: Kayger12
I decided to switch out to Red Line and send a sample of the RP to Blackstone.

... what conclusions I can draw from these kinds of numbers (if any).



Not much knowledge on gear oil from me, but my conclusion is that you did right by switching to Red Line.

RP could have washed out wear metals that were left behind by the original fill. Synthetic oil can do that in an engine, and it might do it in a rear end.

 

[Kayger12]

^ Interesting. I didn't know that that was a possibility.

Thanks for the info.

 

[Rob_Roy]

The oil stayed in grade, and generally seems to have held up well. The wear metals....any chance this is a limited slip type differential?

 

[Garak]

Kayger12, I'd suggest that Loobed is right about residual stuff being left behind. I'm no expert on differentials either, but if you ask me, a rear end would be worse than a differential for trying to get rid of factory fill contaminants, with no filter, and drain procedures and methods all over the place.

A local, trusted transmission/differential guy has stated basically the same on several occasions. He was always in favour of removing the cover and cleaning, or at least doing a minimum of a second change sometime in the near future. And he didn't do it to get people back in his shop right away either; he was very reasonably priced and scrupulously honest.

As for the RP, I don't think there are any problems with the fluid assuming you used the correct viscosity, and it is supposed to be acceptable in limited slip differentials without any further additives. Take it for what it's worth though, since I'm certainly no expert.

 

[oliveoil]

How many miles on the diff?

 

[Kayger12]

Thanks for the feedback.

@Rob- This unfortunately isn't a limited slip diff.

There were 63k miles on this diff when I drained the RP.

Prior to that, it went 47k on the original gear oil (the car had 46k when I bought it).

 

[01rangerxl]

I hope it's not serious as I have had the same fluid in my truck for almost 35K miles now. No problems here, but I haven't drained any, just checked the level/color at the fill plug.

Loobed might be right about the residual metal. I drained the factory fill at 55K, added Valvoline Durablend, then drained that at 82K and filled with the RP. The Durablend was kind of dirty for only 27K miles, so it probably did mix with some residue that was left in the diff.

 

[Jim Allen]

Kayger12: This is difficult to interpret accurately because it was a followup from another oil. Blackstone was pretty vague too, in case you hadn't noticed and that's a "tell." Then you switched gear oils and the next test will equally as difficult to properly interpret. Most likely, the next test will show less metals because what was in there will have been well washed after the previous short run and the mistake will be to think it was the Redline that did it. The only way to get a "clean" read on the oil is to replace the oil with the same one and sample it a second time and then do several other samples over time to get a trend for the metals. At this point, these are tea leaves that cannot be read.

It would help to know what oil was used previously and how long had it been in there prior to the RP change.

With regards to RP Max Gear, I have heard the usual internet "My Oil's Best" babble putting it down but nothing documented about diff failures... and I've been listening. If you have seen some, please detail them or the source. That's just me being interested in following up, not a challenge. Frankly, I don't believe most of what I "hear" in that regard and it has nothing to do with the RP brand. It's no worse than any other brand, better than many, and they all have a basic level of quality that pretty much relegates any major failures to the category of "other causes." Most gear oil, from the least expensive dino to the most expensive boutique synthetic, is too good to be the cause of a diff failure in and of itself. There are rare exceptions.

 

[Kayger12]

Thanks Jim. I definitely am at a loss as to what conclusions, if any, I can draw from this.

The previous oil was the BMW factory fill. It was in for 5.5 years/47k miles. I changed it out for the RP shortly after buying the car.

I know that looks don't mean much, but the factory diff fluid did not look terrible when it came out, and it was not low on fluid.

Most of what I've heard (negative) about RP has been conjecture. I asked the most recent poster on a site I frequent to post up some supporting evidence as he indicated he had read plenty of bad things about RP. He posted the following:

Originally Posted By: zhp43867;159451
It seems most of the evidence is differential related, but there are some complaints about the transmission fluid too.

A major argument/debate thread:

[URL]http://m3forum.net/m3forum/showthread.php?t=309026&highlight=royal+purple[/url]

Amsoil analyzed a bunch of competing fluids, unfortuantely the link on amsoilds site is down, but here's the surrounding discussion:

[URL]http://www.m3forum.net/m3forum/showthread.php?t=327800[/url]

A bunch of E36 M3 owners differential's failed and they were all running RP:

[URL]http://www.m3forum.net/m3forum/showthread.php?t=320821[/url]

A quote from M3F



Non BMW, transmission related:

[URL="http://www.rx8club.com/showthread.php?t=222036"][URL]http://www.rx8club.com/showthread.php?t=222036[/url][/URL]

[URL]http://g35driver.com/forums/reviews/113443-mt-gear-oil-royal-purple-not-so-good.html[/url]

Now not all of that is specific to BMW or transmissions, however I would still stay away from the transmission fluid given my own experience and that of other owners with other makes of cars.


Again, interesting info-- but it's mostly circumstantial evidence at best.

As for the trans fluid warnings from people-- I also had a RP Synchromax sample done with this diff sample. That ran for 16k miles in the 6 speed Getrag manual trans and performed very well.

 

[Jim Allen]

Good response, thanks.

The Amsoil test is often waved around as the end-all-be-all documentation but it's pretty hard to choke down as "unbiased." We've debated it here ad nauseum and reached no solid conclusion. Nor could we ever. Some have accused Amsoil of falsifying data. I wouldn't even start down that road, as they are a basically reputable company. Nor can I believe RP can turn out extremely poor oil with any regularity. I have to assume that the universe dumped on RP by letting Amsoil get hold of one of the occasional bad batches that all companies turn out sometimes. I suppose one can't blame Amsoil for taking advantage of it. The fickle middle finger of fate I guess.

Don't know anything about these BMW diffs. Some diffs are notoriously hard on oil... two that come to mind are the Nissan Titan and the Honda S2000, both of which have a small oil capacity and a smallish ring gear in relation to the work they have to do, so they run hot and hotter. This also plays a part in an oil choice and you want the best if you have one of the notorious ones. Which oil is best is the big question. The main issue in your sample was the metals. Otherwise, the test looked OK. No excessive shearing. Decent flashpoint. Would've been interesting to have tested the FF oil. Well I guess you're hooked enough to follow up again and it'll be interesting to see what comes up next time.

 

[INDYMAC]

Is this an M3 differential? Have you been able to find any other UOA's with the same application? Short of having a good historical trend going for yourself, it may be all that you can turn to for alternatives that might perhaps work better.

I recently read this LE white paper on how to choose a gear oil. It's easy to read and makes sense.

http://www.lelubricants.com/documents/resources/purchasinggearlubes.pdf

I use LE 1605 Duolec SAE 110 in all my rear diffs (Torsen, Gov lock). It's outstanding.

Good luck with your BMW.

 

[INDYMAC]

I just saw it's a 330ci. Beautiful car!

 

[Doug Hillary]

Hi,
Kayger12 - Such a single pass UOA is probably acceptable. You need to trend UOAs for them to become meaningful. The viscosity appears to be good and the following condemnation limits for wear medals are indicative (but not absolute by Manufacturer)

Fe - 1000ppm
Cr - 5ppm

Some carry-over contamination may have been evident in the numbers and especially the Cr

 

[Kayger12]

Originally Posted By: Jim Allen
Well I guess you're hooked enough to follow up again and it'll be interesting to see what comes up next time.


I'll definitely follow up and post the results from the next sample when I change it out again. Thanks again for the help and info.

Originally Posted By: INDYMAC
Is this an M3 differential? Have you been able to find any other UOA's with the same application? Short of having a good historical trend going for yourself, it may be all that you can turn to for alternatives that might perhaps work better.

I recently read this LE white paper on how to choose a gear oil. It's easy to read and makes sense.

http://www.lelubricants.com/documents/resources/purchasinggearlubes.pdf

I use LE 1605 Duolec SAE 110 in all my rear diffs (Torsen, Gov lock). It's outstanding.

Good luck with your BMW.


Not an M3 diff, unfortunately. It's an open diff. Thanks for the link.

Originally Posted By: INDYMAC
I just saw it's a 330ci. Beautiful car!

Thanks!

Originally Posted By: Doug Hillary
Hi,
Kayger12 - Such a single pass UOA is probably acceptable. You need to trend UOAs for them to become meaningful. The viscosity appears to be good and the following condemnation limits for wear medals are indicative (but not absolute by Manufacturer)

Fe - 1000ppm
Cr - 5ppm

Some carry-over contamination may have been evident in the numbers and especially the Cr


Ok. Makes sense.

Thanks to everyone for the helpful feedback.

Much appreciated.