08s2000CRbackinblack

Can I use this or does it contain a friction modifier. It says it contains a limited slip additive. How bout the mobil syn gear lube ls Thanks

w00t692

When they say that they are almost exclusively referring to clutch pack type LSD's.

I always use Mobil 1 in my diff.

08s2000CRbackinblack

i read that one person was using royal purple but really no one esle had any feedback about it. any one chime in? please

redlineracing

I've tried many gear lubes over the years(RP,GM,PZ,others) and I like Amsoil SG 75-90 best of all.

It DOES containt limited slip additive.I run it in the Z06 & the S2K.

As a general rule,I change the trans/diff at the same time( of course the fluids are not the same)...every Spring or 15k miles...whichever comes first.

\rlr
carolina

slipstream444

Royal Purple products are terrible. I have personally experienced an oil related failure using their gear oil - and RP does NOT back their product.

Below is a link to a white paper commissioned by Amsoil that outlines a comprehensive battery of every meaningful industry standardized test conceivable for gear oils.
Say what you will about the test being paid for by Amsoil. The bottom line is an independent lab can't afford to be anything but objective when conducting tests. If they loose credibility, they go out of business. Amsoil could have conducted the tests in their lab, but it would defeated the purpose of demonstrating objective results. BTW - every one of the manufacturers have verified the performance results demonstrated in the tests - and none have challenged them.
Amsoil Severe Gear does not come out in the number one position in every test - but it performs in the top 10% in every test - and not one failure in any of the Pass-Fail tests.

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

The tests demonstrate the importance of a gear oil with not one or two good operating characteristics - but good properties across the spectrum of operation. RP and Lucas oils are the worst overall performers in the test. They perform well in a couple tests, and then fail most of the other tests. I personally believe that's because those companies focus more on marketing and less on product quality and characteristics.

People get emotional or take defensive positions based on "feelings" when it comes to oil. I can't believe the number of posts that state "I use Brand XX oil and Love it!" or "I love the way this oil makes my car feel". It makes my skin crawl to see or hear that crap. Most of that is self-gratification and justification for believing marketing hype and then blowing money on a particular product. I personally make decisions based on expert advice, empirical performance tests, and years of personal experience.

Amsoil SG 75W110 is the perfect oil for OEM diffs, and for street driven modified diffs. You can use the 75W90 in colder weather with no problems. 75W140 is good for track driven modified diffs. The SG line from Amsoil is the best gear oil available today IMHO (with tests to back it up). Amsoil gear oils come with friction modifiers built in, and you can add more of their modifier (see their site) if you have a noisy clutch-type diff.

INDYMAC

Thanks for sharing your experience Slipstream. How in the world did you try to prove that the RP gear oil caused a diff failure, in your own mind and theirs? How did you know for certain that there wasn't a metallurgic defect or some other facilitating damage done prior to the RP fill? Just curious...

slipstream444

The axle was a Dana A44 on a Jeep Grand Cherokee. The vehicle had about 55k on it. I had been running Amsoil Series 2000. I took the vehicle into the Jeep dealer to confirm what a noise was that was coming from the right rear of the vehicle. They essentially took the outboard portion of the axle apart to look at the outboard bearings. The bearings looked brand new and they thought the noise was more likely the parking break (drum inside the rear disc).

I didn't have any spare Amsoil when I took it to the dealer. The Jeep and Toyota dealer pushed Royal Purple at the time and gave me a good deal on the gear oil and free installation.
I watched the entire process because the dealership was sensitive to my desire to see what was being done to my vehicle. I had a great rapport with the dealer principle, the service manager and the mechanic.
Everything was assembled correctly and topped off to the proper level. I drove the Jeep for less than two weeks and the entire rear end (not just the right rear) got significantly noisier. I took it to the dealership and they discovered all of the bearings were shot (the RP was almost black coming out). My Jeep was no longer under warranty. Additionally, I found out the dealership had just experienced a few problems with other vehicles that had Royal Purple installed (the mechanic told me). However, the leadership from the dealership would not confirm what the mechanic told me - and I protected the mechanic who had personally called me. The dealership refused to pay for the repair. They offered me a max blue book trade in on my Jeep, and a dealer cost (not invoice) deal on a new Grand Cherokee. I didn't want to have anything else to do with any Chrysler product and turned that down (I had been waiting for the new RX8 to come out as well). That was the closest I could get them to cover the problem. The dealership immediately stopped using and selling Royal Purple - and I got word from one of the other employees they offered free services to any vehicle they had installed Royal Purple. The service manager directed me to the Dana regional rep in Oklahoma City. I limped my Jeep over there and paid to have the axle rebuilt. They took it apart and immediately asked me what gear oil I was using. I told them RP, and they immediately told me it was an oil related failure - and one of several they had seen.

In two weeks all of the bearings were shot and the gears began to polish. I called RP to see what they would do for me and the representative laughed at me. They said there was no warranty on their product and I couldn't prove it - then he hung up.
I'll sum it up: My diff failed within two weeks of using RP, the Jeep dealership quit using RP after my diff failure and offered other customers free gear oil changes, the Dana factory rep said they had several RP related failures to include mine - I can tell you I didn't have to stretch the facts to come up with a reasonable conclusion on this. Royal Purple is garbage. The company does NOT cover their product. The white paper I provided above demonstrates that their product is below substandard in almost every industry standardized test (Castrol mineral based oil performs significantly better). Use what you want. I can't think of a reasonable person who would use the product even based on the white paper results... but I've heard of stranger things.

Amsoil covers their product. If you have what you believe to be an oil related failure - they tell you to keep a sample of the fluid and to ship the damaged parts to them. They will spend the time to determine the mode of failure. While it's not convenient by any means - at least they care enough to offer, and they want to know if there is a problem with their product.

I guess I can thank RP for one thing - the experience hastened my S2000 purchase. I traded in the Jeep after it was repaired by the Dana regional depot. I bought my 2003 S2000 after I was disappointed with the RX8, which I had been waiting to test drive (I was the third person behind the dealership owner and sales manager to drive the first one in OKC). I waited to buy the S2000 because I wanted to see what the performance of the RX8 was in comparison (I'm not really a convertible guy). I had owned two RX7s and was a rotary fan. I'm not a fan of the RX8.
I ended up with a new 2003 S2000 in 2004 because it arrived with a second shipment of 2004 AP2s to my local dealer. I had been eyeballing their test vehicle because I liked the AP1s better, but would not go for an abused tester. The dealership didn't want the new 2003 car mixed in with their 2004 stock - so I got a killer deal.

INDYMAC

Thanks for the long explanation Slipstream. That's very unfortunate.

But being an unbiased reader here, I'd have to say that I believe the rear end was already headed for its grave before you even introduced the RP. I base this on the fact that you were already hearing unusual noises before you took it to the dealer with the AMSOIL in there. I also don't have much appreciation for the Jeep Grand Cherokee reliability either, especially the drive train. It's possible that the RP accelerated/exacerbated the deterioration, but hard to say for sure. I'm certainly no fan or plan to be of RP.

If it were my vehicle, I would have laid the blame on Dana first, then AMSOIL, and then the dealership for not finding the problem while you were in there on your first visit. But that's typical of dealerships to recommend bringing it back when it's really broken, and then they replace the part.

That's pretty much how I would resolve my feelings about the occurrence. But I also can understand not liking the RP brand or customer service too.

redlineracing

Did the trans/diff fluid change today.

Trans=Amsoil 5-30 Man Trans
Diff=Amsoil Severe Gear 75-90

\rlr
carolina

slipstream444

The dealership didn't replace any parts - there were none to replace, and the vehicle was not under warranty.

Perhaps my unfortunately long write-up wasn't clear enough - the rear-end was proven to be fine by the initial inspection for the noise coming from the right rear. I personally held the bearing in my hand that was being looked at as the possible culprit - and it looked as good as a new one. The noise culprit was the parking break shoe that was slightly rubbing on the inside of the drum portion of the rear disk (the rear break was a disk and the parking break portion was a small drum integral in that disc). The noise was similar to a bearing noise, but resolved after everything had been reassembled and the parking break shoe had been adjusted. I personally inspected the gears while the rear cover was off and they looked perfect - with little to no observable wear other than a normal wear pattern (which the mechanic had pointed out). There was very little wear apparent - as usual with Amsoil gear oil (Series 2000 at the time). The AMSOIL 75W90 that was in the rear end came out CLEAN with around 11,000 miles on the clock. Amsoil was not the problem and the axle was fine prior to the installation of the Royal Purple - I'm not sure how the logic escaped you.

The difference after two weeks - to include the noise being completely different, and coming from the entire rear end - was night and day. The bearing that had been previously inspected to be in like new condition, that I had held in my hand previously, was now worn beyond normal limits; the fluid was almost black when it came out; the gears that had lower than normal wear had a distinctively polished look to them - nothing the dealership had done in the original disassembly/reassembly process would have caused any of those problems... I watched the entire thing. The only variable that can be pointed to was the newly installed Royal Purple 75W90 fluid.

Two separate employees at the Jeep dealership that I personally knew told me there had been other complaints about Royal Purple, and the dealership decided to pull the product from their shelves and stopped using it immediately after my problems. The Dana regional depot and rep (which were NOT related to the dealership in any way - a separate business) stated the damage was an oil related failure - in that the rear end looked like it had been running a fluid well outside the correct viscosity range. I verified the viscosity when it was going in the vehicle - I held the bottle as the tech was pumping it into the diff - I had opened the bottle for the tech. The Dana rep stated they had seen several oil related failures tied to RP within a short period of time.

I hope the logic is much clearer - the damage followed a very clearly defined path and timeline. You can't blame Amsoil for damage and a failure that occurs after the fluid has been removed and replaced with a new one any more than praise RP for the clearly low level of wear present in the rear prior to its installation.

There was no hidden failure mode - the mode was excessive wear following the installation of a new fluid - period. The original noise was the right rear parking brake - which they suspected, but decided to check the outboard bearing just in case because it only took another 5 minutes to get to once the other stuff was taken apart. The magnet on the bottom of the diff cover had little to NO fuzz or anything on it when the diff was originally drained for the original inspection (the tech commented on how clean it was - showing the Amsoil was doing an excellent job). It was covered in fuzz and noticeable metal flakes and slivers when the RP was drained. It doesn't take Dr Deductive Reasoning to figure out that one - it was THAT obvious to all involved.

Once again - I apologize if my original explanation wasn't clear enough. Hopefully this cleared up any confusion.