vetteman9368

MAJOR difference vs dexron III. Changed it today and it was instantly smoother than it ever was on ATF. And this is with 121k on the clock

cjcvette

I replaced mine earlier this week with RP synchromax as well. I didn't see any difference initially. So far I have ~50 miles on it with no significant difference.

As the second owner I don't know what fluid was originally in it, but i was dark red - so perhaps it was the original factory fill.

Still hoping for some improvement - that and I probably need to do a shifter alignment. Interesting to hear of the improvement you experienced - that seems to be the most common response.

itzza427

I used it about a month ago,,and love it.Shifter was very cranky getting int first after sitting at a light in neutral. Now goes in all the time!! I too did the diff.!!!

WKMCD

The T56 transmission is really sensitive to fluid quality. I've been running RP for a while now and it's the $hitz! I also run RP in the differential.

vetteman9368

I did the same thing yesterday, did the diff too

BillY2KFRC

Just did mine last week with Syncromax and am very happy. Noticed a huge difference from the stock fluid in my 32k mile 03 Z. Made my MGW shifter far, far easier. Almost seems to pull the car into the next gear now.

dwestsr

It must have something to do with Transmission condition, because most of the folks that see improvement that I have read about here, have either high mileage or some syncro wear/damage. It made no difference at all in my 2004 with 20k vs Mobil 1 synthetic ATF.

jfrc

my car is mostly used for autoX, and i try to change all fluids each winter
i went ahead and did the trans and rear end with RP, what a difference in shifting- definately worth it

cwalsh

When I did a clutch install I changed fluid to Mobil 1. I must say I do not like it. Shifter feels stiffer when going into gear. I will definately be trying out the Royal Purple!

Chris

diyguy

I just finished a discussion with the parts guy at the local auto parts shop. I had 4 quarts of Mobil 1 Synthetic in my hand and was reading on the label and NOWHERE did it say anything about being Dexron III compatible. (2000 model MN6).

So, he says "if the manufacturer says Dexron III, that is what they mean. Hell, I'd love to sell you the much higher price Mobil 1, but I don't want to have to pay for your transmission" So, I scratched my head and thought about it, then left the Mobil 1 where I picked it up and walked out.

Now, upon further forum search, it appears many have gone completely against the grain and swear by other 'synthetics'. My question is WHY?

I can not find anything to substantiate anywhere that GM sanctions the use of anything but Dexron III. I use Mobil 1 oil as per the manual and will be doing the diff with GM branded and correct part numbers for that as well.

So, why is it, or who says any of this other snake oil crap is any better?? What statistics can anyone quote that other stuff is any better?

My kid is a heavy line mechanic at Subaru and says it is a complete and total waste of money to use anything ohter than what the manufacturer states as 'manufacturer approved'.

So, come on - the challenge is on..... WHY is anything else "better"

I am all fricking EARS at this point

vetteman9368

auto parts counter guys and line mechanics are not where i would seek out high performance advice

cwalsh

That's a good point on what the manufacturer approves. But with higher hp n tq numbers its nice to know someone makes a fluid of higher quality. On the Mobil 1 bottle it does state that it is compatible with dexron 3 but it also adds its compatible with every other creation of fluid. It used to be specifically dexron 3. All though the last time I bought it was over a year ago for my camaro. Just my .02 worth.
Chris

hattitude

Out of curiosity... Has anyone used the Dexron VI..?

"General Motors DEXRON®-VI Global Service-Fill Specification

During early 2005 General Motors released a newly developed automatic transmission fluid (ATF) for the factory fill of all GM Powertrain stepped gear automatic transmissions. The new fluid provides significantly improved performance in terms of friction durability, viscosity stability, aeration and foam control and oxidation resistance. In addition, the fluid has the potential to enable improved fuel economy and extended drain intervals. Since the performance of the new fluid far exceeded that of the DEXRON®-III service-fill fluids available at the time it became necessary to upgrade the DEXRON® service-fill specification in order to ensure that similar fluids were available in the market for service situations. This latest upgrade to the service- fill specification is designated DEXRON®-VI."

byte_me

what he said

I can tell you this- in my former life I was a mechanical engineer, we adopted an airline industry maintenance practice called Reliability Centered Maintenance at several water treatment plants [read very large, high horsepower pumps and complicated gear reduction units] one study, we replaced the OEM oil fill with that of a compliant synthetic oil and ran two gear units online with the same amount of pump turning. After several months we pulled the units and inspected the gears and wear parts- the synthetic unit not only ran cooler, but the wear faces of the machined parts looked brand new, the conventional oil unit looked terrible, the higher heat caused the friction surfaces to become worn and scarred. Both units were brand new from the factory and all we did was change the synthetic oil in one. The maintenance cycle used was that called for by the OEM for normal maintenance and inspection...

In short, the unit with the synthetic oil was simply drained and re-filled; the other unit had to be rebuilt.

The concept of this maintenance practice is to reduce the MTBF of equipment while maintaining the availability of them at close to 100%, this way you get the most use out of the equipment without performing un-needed and costly maintenance on something that didn't need it.

I run the compatible synthetic oil in everything I own.

diyguy

And.....just where did you come up with that highly scientific statement? Maybe not 'good ole Joe' at the parts store, but I would be intensely curious how you can make a blanket statement that a heavy line ASE Certified mechanic (engines, tranny's, diff's) "are not where one would seek out 'high performance' advice.

UH.... Last time I checked, the Subaru WRX-STI has "high performance technology" that other manufacturers drool over.

So, again, if you would be so kind as to explain that idiotic and generically dumb *** statement, I am again---->


Then back to the original question.... Who can show in repeated example after example based on hard facts, numbers, scientific explanation this 'lets all follow the sheep' mentality towards anything other than GM branded is superior to all the rest out there?

itzza427

Well I used it in diff and tranny,,Solved a balky shifting tranny problem for me,,I'm happy!Fresh factory fill may have done it as well,but R.P. has good rep with the racing crowd and they won't use it if it doesn't work.Car Craft magazine did dyno runs with conventional then R P and gained power and torque.There must be something to synthetic or G M wouldn't use Mobile 1. Bottom line use it if you want to,,no one is twisting your arm either way.Your car ,your money,do as you wish!! I like the results I got so I'll use it in mine and share my results with any one that is interested and every one can take it at face value and make up their own mind.A few extra bucks once in a blue moon for a tranny refill isn't going to break the bank or shatter the earth. Syncromax is safe for the older trannies,it worked for me,,and that's good enough for me!!

C5R USA

Well stated Gene Royal Purple FTW

vettenuts

There is a lot of good information on "Bobistheoilguy.com" with regards to oil and transmission fluids. There are also many there who have done used oil analysis to help determine which oils are doing a better job protecting internal components. I may be wrong on this, but I also believe that both RP Synchromax and GM Synchromax are not synthetics, but rather have viscosity characteristics that allow better synchro speed matching during a shift, i.e., too slippery in a transmission is not necessarily a good thing. (They may be synthetic blends though).

vetteman9368

I know at least 2 dozen "heavy line" ASE certified mechanics and maybe 3 of them know anything related to high performance or racing. I work in the high performance aftermarket, I see this **** every day.

Joe so and so at the dealership told me....... well 95% of the time Joe so and so at the dealership doesn't know his *** from a hole in the ground. Todays dealer and "line" mechanics are parts changers. If their computer or service manual doesn't tell them how to find the problem they're usually lost. There's a reason they call them "technicians" and not mechanics anymore. All the ones with any real mechanical knowledge, left the dealership a long time ago and probably own their own shop

duneinit

I have been using RP in my 2004 ZO6 in the engine, trans and diff for the last 3 years over thirty thousand miles and would recomend it to anyone who wants my 2 cents worth. In the trans the biggest different was the noise level using RP the gear whine is gone. A friend of mine owns a transmission shop and according to him the main advantage of using a Mobil 1 or RP is that it will not break down under high temp. If you are doing any type of track days or open road racing your trans and diff are going to get extremly hot. I have had my High Temp Light come on for the trans during an open road race, drained the RP it looked almost like it was right fresh out of the bottle.