Adam3612

I'm wondering that too. RP is a gimmick, IMO its the same as every other synthetic out there except it has purple dye in it. Thats all besides the fact that it doesnt meet Chrysler MS-9224 so I wouldnt put it anywhere near my transmission.

seajk

Nobody going with pennzoil platinum? There are some test out there some where with good results if you google that vs. mobil 1.

JCKnauer22

i use RP in my jeep, but i didn't decide to go with their products simply because they're purple. that's an outstandingly ridiculous reason to choose a lubricant. i went with it because it's a synthetic and i'd heard good reviews. i haven't found a reason not to continue running their products, and until i do that is what i'll run.

Percheron

I just put in RP Syncromax in my 6sp and am amazed how quiet the thing is now. It shifts pretty much the same, a bit better, but my goodness what a change in noise. I know the RP does not have the MS344907459321239 or what ever rating, but since the tranny was already rebuilt under warranty at 4k miles due to bad bearings (7 were replaced), I figure it will probably grenade anyway (even though I'm gentle on my stuff), might as well have it spin smooth until it does.

Also put in Castrol ATF-4 synth for the transfer case. It too is very smooth and quiet now, shifts in and out of 4wd much, much better.

Adam3612

I didnt say thats why people use it, I just said its a gimmick and that it probably isnt any better than the other synthetics on the market. I did forget to mention that its typically more expensive than the others and as far as I have seen shows no greater benefit, thats the point I was really trying to make, sorry I didnt point that out in my first post. First hand i've seen some friends have trouble with transmissions that they put synchromax in but who's to say the RP was at fault, then again who's to say it wasnt

RN M OVR

I use Mobil 1 synthetic for everything. Not a problem. If anything I get better response and a smoother-sounding engine.

Adam3612

Thats what I use for everything too, had great luck with it in every vehicle i've owned. The only place I dont use it is in the diffs and the tranny, can't get Mobil 1 gear oil around here in anything other than a 20 litre pail and correct me if im wrong but they dont make synchromesh do they?

Adam3612

When I went looking for synchromesh/tranny fluid about 2 months ago I found RP in two small independently owned auto parts stores and nowhere on either bottle did it say that it met Chrysler MS-9224. I was desperate to find something that I could use in the tranny so I even went as far as to email Royal Purple and ask them and the reply I got was that Synchromax was not currently licensed by Chrysler so they couldnt put that it meets MS-9224 spec on the bottle, they didnt say why. I'm not questioning your knowledge, if you're an HD mechanic than you know alot more about alot of things than I do but even now when I check the RP website and product sheet for Synchromax nowhere does it say that it meets spec, im not trying to be an ass but I am trying to drive home an obvious point.

Percheron

No, it's probably not any better but it WAS the only synth oil fluid in stock at the local major autoparts store to have the specific "For Manual Transmission with Syncros" on the bottle. The rest of the aisle was motor oil and AFT of all different flavors.

tpm152

I actually recently contacted RP with some questions about what fluids to use for different parts of the Jeep as I have had GREAT success with using RP. They were saying that their fluids weren't certified as MS-9224 and ATF+4 because their fluids were made from purely synthetic feedstock. Both of those Chrysler specs specify the use of petroleum-based feedstock (yes, ATF+4 is petroleum-based contrary to popular belief). Of course being a synthetic oil manufacturer they don't ever use standard petroleum feedstock: hence their inability to certify their lubricants as such.

For everyone's information, royal purple actually recommends the use of Sychromax in BOTH the manual transmission (6 speed) AND the NV-241 transfer case. Their reasoning for not using ATF in the TC is because their ATF does not contain the synerlec additive that makes their other oils so slick and such good protection for metal to metal contact surfaces because of the clutches that are in automatic transmissions that would not work correctly with it. There are not any clutch friction surfaces in the TC so there is really no reason to need ATF in there. Chrysler probably just uses ATF in there to try to lubricate with the least viscous fluid in there to try to get the max fuel economy out of our JKs.