Don't want this to be a thread about which oil is better than any other. I have bought this oil and have a few questions.

Just went to a local shop, wanting to switch my fluids out as I am well overdue for the diff's and transmission.

Guy told me that the Royal Purple gear oil 75W90 goes into the transmission as well, is he correct?

Also can I put this in the transfer case?

Thanks alot.

fraynes1

 

The T-case takes ATF+4.

Transmission oil must meet the requirements of DaimlerChrysler Material Standard MS-9224. Lots of brands do, and will say it on the bottle.

Front axle oil: SAE 80W-90 (API GL-5).

Rear axle oil: 198 RBI (Model 35) and 226 RBI (Model 44)
SAE 80W-90 (API GL-5) or equivalent.
For trailer towing, Synthetic Gear & Axle Lubricant (SAE 75W-140) or equivalent. Models
equipped with Trac-Lok require an additive. (unless the synthetic oil already contains the additive)

 

Put Synchromax in the transmission, 75W90 in the diffs, and Max ATF in the transfer case if you want to go over to pure RP. The diffs will make the biggest difference, I could actually feel a slight seat of the pants power improvement after the swap without even looking for it.

 

RP manual trans fluid is great stuff, I put it in my SRT-4 and the tranny was smooth as silk afterwards.

 

I put RP in my manual and felt an improvement in shifting right away. CM

 

FYI - Synchromax does NOT meet Chrysler MS-9224 and does not say anywhere on the bottle that it does, if you contact RP they will tell you the same thing but also still tell you to use it.

If you want something that meets spec try Pennzoil Synchromesh, Quaker State Synchromesh or MOPAR Manual Tranny fluid.

 

This is what is on the bottle I have, they did not have Syncromax.

Max-Gear High Performance Automotive Gear Oil.

- Meets Performance Requirements of API GL-4 and GL-5

- Contains Limited Slip Additive

- Great for Manual Transmissions Requiring GL-4 or GL-5 fluids

- Meets Performance Requirements of MIL-L-2105E

I don't want to screw this up, as far as I can tell this is ok for the Manual Transmission.

 

The new transmissions require an MTF fluid not gear lube. It is closer to motor oil than gear lube in consistency (if I remember right anyway). Run some Google searches for Synchromesh MTF and you should find several brands that should work.

 

How do you figure it's OK for your manual transmission, when it doesn't say it meets MS-9224?

I am speaking from experience when I tell people to use MS-9224 when the book says to. I put a good synthetic gear oil in the manual tranny of my '02 Dakota, thinking it would be better than what the owner's manual said to use (4549636). After a very short time, it started to grind when shifting.
I drained it all out and put in the correct oil, and all was well again.

The additives in the MS-9224 are correct for the synchronizers. Some oils will actually eat away the friction surfaces, or at least keep them from operating properly.

edit: Where it said MS-9224 in parentheses, I meant to write 4549636, to illustrate I had deviated from the owner's manual.

 

Agreed! DO NOT use gear oil or anything else in your transmission unless it states in your owners manual you can do so, you'll burn your synchro's and who knows what else out of your tranny. It's seriously important you use something that meets MS-9224. Go ahead and use RP Synchromax, maybe it's a good product I dont really know, but if anything happens to your tranny you're on your own to have it fixed because it doesnt meet MS-9224. I know a few engineers from Imperial/Exxon and they all say they would never put anything made by RP near their vehicles.