# Royal Purple Good for our Manual Transmissions??



## OnlyTaurus (Mar 20, 2012)

I bought 3qts of RP MaxGear 75w90, made for GL-4 and GL-5 replacement, and am changing out my fluid in my trans today.

I, however, came across several forums that claim RP is horrible for yellow metals(brass, bronze, copper, etc.), and became concerned.

So, I went onto RP's website, found the gear oil, and their description is as followed. Looks like we may have another fluid option for our transmissions.

I will try it out and post later on with thoughts.

*Max Gear – High Performance Gear Oil*

Max Gear is recommended for use in truck and automotive front or rear differentials, manual transmissions and lower gear units of marine engines that specify use of an API GL-5 or GL-4 fluid. *It is non-corrosive to soft yellow metals (brass, bronze, copper, etc.) and synchronizer safe*.

Max Gear is an ultra-tough, high performance automotive gear oil designed to provide maximum protection to heavily loaded gears while maximizing power throughout the drive train. Max Gear outperforms ordinary gear oils by combining the highest quality synthetic oils with Royal Purple’s proprietary Synerlec additive technology. Max Gear makes gears run smoother, quieter, cooler and longer without overhauls. Max Gear is formulated with a friction modifier additive – no additional additives are necessary.

Max Gear is available in the following viscosities: 75W-90, 75W-140, 80W-90, 85W-140 and SAE 90


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## sciphi (Aug 26, 2011)

Give it a shot and see. My quibbles would be the GL-5 specification. Synchros don't need all those extra EP additives, and the transmission in general isn't subjected to the extreme forces a hypoid-gear differential is subjected to.


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## OnlyTaurus (Mar 20, 2012)

Well, I already noticed a huge improvement... transmission noise has extremely subsided. Of course, it doesn't help when all that drained out from the factory was just over a quart.. Nonetheless, the trans is much quieter now.

Shifting seems easier too, a little. It being a high performance gear oil, I wouldn't assume it would smooth out shifts by much, but it did help.

I'm going to continue to use it and see how it performs when the clutch is good to go, but all in all I'm satisfied with this fluid at the moment.


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## NBrehm (Jun 27, 2011)

I did that with my T56, ran great for about a month then the synchros disintegrated. Came to find out the T56 can't use synthetic fluid and had to have non syn Dexron III. The culprit was the paper blocker rings the T56 uses, the syn fluid ate them up and the synchros went adios. Don't know if the same applies here but be wary when it comes to transmissions.


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## sciphi (Aug 26, 2011)

Keep us updated. I'd still be leery of running a 75w-90 that is meant more for gears, but can be used in transmissions.


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## Starchy (Aug 30, 2012)

I thought you can go from a GL4 to a GL5 but not the otherway around, meaning that gl4 is gl5 compatible but gl5 is not gl4 because of the brass. And as far as the paper blocker rings... I just did a search on Google cause i did not know what those were....(Im a Noooob) Anyway it seems like every link was talking about the t56 with those, and no other trans... and a bunch of people with issues... My guess is they would have strayed away from that, and i feel like I would have come across that issue when i was researching this trans on the vauxhaul forums. They have had the M32 trans since 06 at least... btw M32 supposedly stands for Max320 Nm (just a little fun bit of info)


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## NBrehm (Jun 27, 2011)

Like I said, I'm not familiar with the internals on the Cruze manual trans, just saying to be cautious


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## OnlyTaurus (Mar 20, 2012)

I'll keep an eye on it and keep this thread updated after some miles are driven.

But like I said before, it feels great at the moment.

I wanted to originally use Amsoil, but could not find it anywhere local. I didn't want to have to order it, so I went with the RP Advance Auto has on sale currently.


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## sciphi (Aug 26, 2011)

Starchy said:


> I thought you can go from a GL4 to a GL5 but not the otherway around, meaning that gl4 is gl5 compatible but gl5 is not gl4 because of the brass. And as far as the paper blocker rings... I just did a search on Google cause i did not know what those were....(Im a Noooob) Anyway it seems like every link was talking about the t56 with those, and no other trans... and a bunch of people with issues... My guess is they would have strayed away from that, and i feel like I would have come across that issue when i was researching this trans on the vauxhaul forums. They have had the M32 trans since 06 at least... btw M32 supposedly stands for Max320 Nm (just a little fun bit of info)


From what I understood, GL4 and GL5 have to do with the type and amount of extreme-pressure additives in the gear oil. In the old days, the extreme-pressure additives that lasted were made using sulfur-containing compounds, which ate up the brass/bronze synchros. These days, with better additive technology, oils with the necessary EP additives for GL5 specification can be formulated to not attack yellow metals. 

I found this thread on Bobistheoilguy.com concering GL4 vs. GL5 gear oils, and why something designed for gears might not be optimal in a transmission: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1137260#Post1137260 

In short, a dual-rated GL4/GL5 gear oil will work, and there are likely better options out there if one isn't happy with how it shifts.


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## Abrunet85 (Jul 29, 2011)

Any updates on your tranny?


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## sciphi (Aug 26, 2011)

Abrunet85 said:


> Any updates on your tranny?


Mine with the Amsoil Synchromesh in there for 35k miles now has been fine. It shifts fine, no grinding (unless I really get on it with my tune and rush the 1-2 shift), and no odd noises. It works when I need it to work. That's about the best compliment I can give something.


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## OnlyTaurus (Mar 20, 2012)

Mine's okay on the RP. Feels great when in the high gears, but second is problematic for me. It's not Royal Purple related, but rather the factory on put a quart of trans fluid in my case, because I drained about 90% of it. Didn't even get a quart out of the trans...


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## Hoon (Mar 18, 2012)

I'm not sure what came out of mine but it wasn't much. Maybe a little over a quart.


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## H3LLON3ARTH (Dec 16, 2011)

How are y'all judging how much fluid to put back in because it tells me to let drain for 10 minutes then measure how much vame out thwn put back the exact same amount.

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## bodeis (Jan 28, 2012)

Im wondering also. Service information says to drain the fluid, measure how much came out and replace only that amount.


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## OnlyTaurus (Mar 20, 2012)

I'm not convinced on the 'put back what came out' bull. My trans was starving. It's been noisy since day one, but figured it would subside at some point.

If you drain your fluid, keep it. It's your insurance.

We've found that transmissions are failing because of heat. Dissipation of heat is very critical of our trans. I actually put a little bit extra fluid in my case.


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## H3LLON3ARTH (Dec 16, 2011)

but how many quarts did you put in.


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## OnlyTaurus (Mar 20, 2012)

I let mine drain out excessively(30-40 minutes), since there wasn't much in it. Maybe there was a gigantic air bubble keeping the other quart of fluid in. Fail..

Service Info says 2.32 quarts. I put in an extra half quart.


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## XtremeRevolution (Jan 19, 2012)

OnlyTaurus said:


> I let mine drain out excessively(30-40 minutes), since there wasn't much in it. Maybe there was a gigantic air bubble keeping the other quart of fluid in. Fail..
> 
> Service Info says 2.32 quarts. I put in an extra half quart.


Not possible. You either leaked it somehow, or it was under-filled from the factory. 

I wonder how much fluid the case holds when you drain it completely, if at all. Either way, 2.5 quarts is a good bet. I don't think over-filling by half a quart will have a negative effect on it, and the extra fluid should provide some extra heat tolerance.


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## H3LLON3ARTH (Dec 16, 2011)

XtremeRevolution said:


> Not possible. You either leaked it somehow, or it was under-filled from the factory.
> 
> I wonder how much fluid the case holds when you drain it completely, if at all. Either way, 2.5 quarts is a good bet. I don't think over-filling by half a quart will have a negative effect on it, and the extra fluid should provide some extra heat tolerance.


I have always wanted to stick a camera in a diffrental housing the drive.

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## sciphi (Aug 26, 2011)

I got just under 2 quarts of fluid into my transmission. No noises or anything after refilling with 2 quarts 35k miles ago. 

Fill with 2 quarts to be sure it is not overfilled. 


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## Greasemonkey2012 (Jul 8, 2012)

i thinking of running the fuchs Titan Sintofluid 75w80 or the other link not sure whats good to help my notchy shifting 

Fuchs TITAN SINTOFLUID SAE 75W-80 synthetic manual transmission fluid 


[url]http://www.opieoils.co.uk/p-60205-motul-motylgear-75w-80-synthetic-gearbox-oil.aspx
[/URL]


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## Abrunet85 (Jul 29, 2011)

I just changed my fluid out today for RP MaxGear 75w90. I currently have 111,131km (69,000mi) and when I drained it It only had 1.5 Qts. I followed the http://www.cruzetalk.com/forum/57-how-library/6627-how-change-manual-transmission-fluid.html and put 2Qts back in and didn't have any overflow out the level plug.


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## sciphi (Aug 26, 2011)

I'm a bit skeptical on RP MaxGear for our transmissions since it's a GL5 gear oil, and the OEM Castrol BOT 303 (for 2012's and presumably 2013's) is a GL4 gear oil. GL5 is not better than GL4, it signifies how much additive is in the fluid. RP says it's okay for yellow metals and synchronizers, so it should be okay there. 

Please let us know how it turns out. If you encounter any hard shifting or grinding, dump the RP immediately for a GL4 gear oil.


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## H3LLON3ARTH (Dec 16, 2011)

sciphi said:


> I'm a bit skeptical on RP MaxGear for our transmissions since it's a GL5 gear oil, and the OEM Castrol BOT 303 (for 2012's and presumably 2013's) is a GL4 gear oil. GL5 is not better than GL4, it signifies how much additive is in the fluid. RP says it's okay for yellow metals and synchronizers, so it should be okay there.
> 
> Please let us know how it turns out. If you encounter any hard shifting or grinding, dump the RP immediately for a GL4 gear oil.


Well the only time its hard for me to shift now is whn I am really getting on it from first to second but everyone still has that problem, I'm likeing it better and better every day.

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## OnlyTaurus (Mar 20, 2012)

sciphi said:


> I'm a bit skeptical on RP MaxGear for our transmissions since it's a GL5 gear oil, and the OEM Castrol BOT 303 (for 2012's and presumably 2013's) is a GL4 gear oil. GL5 is not better than GL4, it signifies how much additive is in the fluid. RP says it's okay for yellow metals and synchronizers, so it should be okay there.
> 
> Please let us know how it turns out. If you encounter any hard shifting or grinding, dump the RP immediately for a GL4 gear oil.


From what I understand from researching, it's a GL4 fluid that is GL5 compatible.

I think its great fluid. The cold mornings are not really affecting the shifting, which is a huge plus to me. And from touching the gearbox after being on the dyno for three pulls, I was very impressed with the temperature. Certainly feels better than the stock fluid did. I'm convinced the heat dissipation is holding its end of the description.

Im gonna side with H3LL, I'm giving this fluid a big thumbs up.

I may try the Amsoil soon to compare.

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## OnlyTaurus (Mar 20, 2012)

Abrunet85 said:


> I just changed my fluid out today for RP MaxGear 75w90. I currently have 111,131km (69,000mi) and when I drained it It only had 1.5 Qts. I followed the http://www.cruzetalk.com/forum/57-how-library/6627-how-change-manual-transmission-fluid.html and put 2Qts back in and didn't have any overflow out the level plug.
> 
> View attachment 12843


I had about half that drain from my gearbox. I was very aggravated, lol. 18k miles..

Needless to say, Im holding onto the fluid to shove in GMs face if my trans ever fails. Its already excessively noisy.

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## sciphi (Aug 26, 2011)

I'll shelve my skepticism for the time being, since the two of you are reporting okay results. 


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## XtremeRevolution (Jan 19, 2012)

OnlyTaurus said:


> From what I understand from researching, it's a GL4 fluid that is GL5 compatible.
> 
> I think its great fluid. The cold mornings are not really affecting the shifting, which is a huge plus to me. And from touching the gearbox after being on the dyno for three pulls, I was very impressed with the temperature. Certainly feels better than the stock fluid did. I'm convinced the heat dissipation is holding its end of the description.
> 
> ...


Better sooner rather than later when the conditions change more or the RP fluid starts to show its age. Just for the sake of a valid comparison that is.

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