wolf8218

Just a warning to all T56 owners out there.

I have used the following transmission fluids in my MN12 and TR6060 transmissions:

1. Stock GM fluids 15000 miles
2. Mobile 1 Synthetic ATF 2000 miles
3. Amsoil ATD 2000 miles
4. Royal Purple ATF 2000 miles

I would like to inform you that if you're thinking about changing to RP, don't! It's the only one of these fluids that plays havoc on my blocker rings. The car can be run for 100 miles and the rings will not operate correctly. I changed to Mobile 1, after first experiencing this issue with RP ATF and it immediately went away.

I don't see how RP can recommend this product as a suitable application for our cars.

The three other fluids behaved EXACTLY the same, and I tested all of the fluids under the same conditions.

READ FIRST

Before posting any responses, please include the following in your posts:

Type of transmission (T56: MN6 MN12, TR6060 Base Z06 ZR1 others im forgetting)
Fluids used and for how many miles
Issues with each fluid
Do you drive your car in the cold at all?
Is your car a garage queen?
Is your transmission showroom stock or has it been rebuilt?
Is your car in storage for long periods?

Let's keep it as scientific as possible not "HE SAID SHE SAID" type of recommendations.

john8642

I've had Royal Purple in my trans for over a year and experienced no problems. When I researched oils to change the trans fluid, there were many posts that said RP worked better than the others.

wolf8218

I don't mean any disrespect but I don't find your reply scientific or useful at all. Reading posts on the internet is different from first hand experience. Plus not all transmissions in the C5 were created equally. Give more details regarding your experience and think hard about how your transmission behaved back to when your car was new.

Lee DeRaud

Let's see if I've got this straight: you're trying to conduct a (somewhat) scientific study and you're waving off your first data point because it doesn't back up your preconceived conclusion. Great methodology...not.
If RP doesn't work for you, don't use it. But I don't find your "study" scientific or useful at all.

Zuti

I believe that John8642 did provide you with firsthand results when he stated that he had used Royal Purple himself with no issues. I use Amsoil Torque drive in my 98 MN6. Butter smooth, especially vs the GM product. I drive my car daily in cold weather and hot and have over 120K on it with no trans issues. Bone stock.

wolf8218

Sorry but I don't consider what someone may have read off of a random CF post to be my "first data point".

My testing already has 8 first hand data points.

Try to keep up with the class will ya?

PS- For the record, I've seen MORE posts on CF stating the opposite, which agree with my findings, that RP ATF causes issues with these transmissions. I'm not really interested in these claims.

Zuti

You are being rather arrogant. You scientific process has it's flaws as well. You are basing your opinion on an assumption that because you changed from RP to something else that RP is the issue. Did you retest, or just assume that was the issue. Is there something else going on with your trans? Bashing others opinions in the guise that you are performing a scientific study is not becoming of forum members. If you have a true scientific study, post you results, trials, re-trials, other possible causes, etc. or just relax and use whatever trans fluid you like without slamming others for their opinions or data sources.

wolf8218

I absolutely did retest/retrial Like I said I've had royal purple in BOTH my T56 and TR6060. Both of these experienced the same issues. My TR6060 now has GM fluid (warranty) while my T56 has Mobile 1 atf. The symptoms experienced with the Royal Purple have disappeared.

This was 2000 miles after a fluid change. No racing, just street driving.

The fact that they're both operating correctly now leads me to believe there's nothing wrong with either transmission.

Results: RP ATF causes issues with C5 and C6 manual transmissions
Causes: Incompatible fluid / out of spec fluid with manufacturer recommended Dexron III standard.

john8642

Only an idiot would claim to be doing a "scientific" study after titling his thread "Royal Purple is not an acceptable Dextron III substitute". Were you home schooled by any chance? The fact that many members here use RP with good results is more useful to me than one person screaming how bad it is.

wolf8218

Our conversation ended with idiot.

Bud Doggin

striper

To the OP, if you were using the RP ATF in your manual, then you were using the wrong oil. Royal Purple makes a correct fluid to replace ATF in a manual trans called Synchromax. This fluid works great. I've been using it for years and many thousands of miles in my own car with no problems.

Lee DeRaud

Nope, not worth the aggravation.

woodman300

what issues? you don't specify what your troubles are and we don't know what year you have. i have heard a few people say the had heard of some problems but no one i know had any first hand trouble with RP Synchromax. i have personally used it in my 2000 for about 15000 miles and it is butter smooth with no problems at all.

wolf8218

My C5Z is a 2002 MN12 (made from 2001-2004) and my C6Z is a 2008 with the TR6060 (made from 2008-2013). I have not used synchromax, because as you will read below, it is even less suitable for our cars. The problem I experienced is pushback from blocker rings under low or no throttle shifting. This is due to out of spec fluids.