DeclareYrWar

i just bought some royal purple 75w90 for my transmission today so i'll let you guys know my opinion on saturday after i get it put in there and my motor swapped in.

deadRX7Conv

Sulfur isn't the only additive used to make GL4 or GL5 gear oils. Moly, ZDDP, Boron, Calcium, Magesium, Teflon, Graphite, Chlorinated compounds, Esters, and numerous other chemicals can be used to increase the load carrying capability of a fluid.

Smell of a gear oil doesn't tell you if the additive package is buffered or not, is inactive or not...... Smell doesn't prove anything.

With ANY diff, I'd recommend a fluid with LSD additive even if it isn't needed. There are other benefits to the LSD additive chemistry. The friction modifiers are high end products. An open diff using a LSD additve equipped gear oil will actually run cooler, have less power loss through it, and should last longer. With an LSD, the more additive you use, the more it will slip, the less torque bias it will have. So, if you want a grippier LSD, don't use the additive or a fluid with it already. Most stock old worn out LSD clutch type diffs might benefit from less or no LSD additive. But, avoid chatter since that will create wear in the clutches. The LSD additive amount can be tailored to the condition of your rearend's LSD. Use just enough to prevent chatter or binding. Thats difficult to do if the fluid is already overdosed with LSD additive. Notice that my recommendations are opposite of what is commonly done. Use a full dose of LSD additive in an open diff. Use as little as needed in a LSD equipped diff.

These are some of the GL5 gear oils that should be considered for added protection over a GL4 gear oil in a manual transmission without negatively affecting the shift quality or synchro life. Lets quote some websites. Notice that they mention GL4, GL5, gearboxes synchronizers, manual transmissions or transaxles, OR easier shifting,

Redline 75w90NS--This GL-5-type geal oil doesn't contain the friction modifiers for limited-slip hypoid differentials. This makes the transmission synchronizers come to equal speeds more quickly, allowing faster shifting and much easier low-temperature shifting.

NEO 75w90HD--NEO 75W-90 HD meets the requirements for GL-4 grade even where manufacturers discourage the use of a GL-5 product. It is recommended for front wheel drive transaxle use where GL-4 performance is specified.

Motul Motylgear 75w90--For all gearboxes and hypoid rear axles without limited slip systems. Performance Standards: API GL4 and GL5 / MIL-L-2105D. Very easy gear shifting.

Motul Gear 300 75w90--Performance Standards: API GL4 and GL5 / MIL-L-2105D. For all gearboxes and hypoid rear axles without limited slip systems. Very easy gear shifting.

RoyalPurple Maxgear 75w90--Max-Gear is formulated to improve the efficiency of rear end assemblies and manual transmissions. API GL-4 / GL-5 Certified.

Specialtyformulations MTL-R 75w90--MTL-R is manufactured using the finest Group IV (PAO) and Group V base oils and is recommended for manual transmissions and transaxles specifying a GL4/GL5 75w90 lubricant.

Pennzoil 75w90 GL5 synthetic--PENNZOIL® SYNTHETIC SAE 75W-90 GL-5 is designed primarily for the lubrication of differentials and manual transmissions requiring an API GL-5 gear lubricant.

Torco RTF 75w90--Recommended for manual transmissions, transaxles and marine outdrive units where an SAE 75W90, 80W90
or 90 is specified. RTF is specially formulated to exceed the load-carrying and extreme pressure wear protection properties of higher viscosity GL-5 or GL-6 gear oils. RTF provides anti-score
protection for high speed, high load and high torque shock-loading conditions, while allowing smooth operation of synchronizers.

Castrol Syntrax/Mulitrax 75w90--Castrol Syntrax is a synthetic SAE75W-90 manual transmission fluid with outstanding thermal stability and synchronizer performance. Castrol Syntrax is particularly recommended for transaxle applications with combined transmission and hypoid differentials Exceeds API GL5.

Lubro-Moly Vollsynthese 75w90-- Allows for easier shifting and quieter operation. Gives outstanding wear and corrosion protection. For manual transmissions, transaxles, and rear axles where GL5 is specified.

And to quote Mazda, please read your owner's manual and factory service manual's fluid recommendations for your vehicle's transmission. SURPRISE. GL4 OR GL5!

75w90NS works extremely well in my transmission, protects better then the GL4 MT90, without any synchro issues while shifting well. 75w90 works great in my open diff rearend.

And, my gear oils get dumped every 30k OR 3 years. So, even if I used a bad sulfur loaded gear oil, it will not have been used long enough to oxidize, wear out the additive package, or take in enough moisture to form acids. Time, heat, and moisture are your synchronizer's enemy. Sulfur is the scapegoat for owners abuse, neglect, and pathetic maintenance habits.

ericgrau

iTrader: (1)

Switching your tranny oil from X to Y should never cause any problems, unless Y is bad in and of itself.

I believe Royal Purple Max Gear contains sulphur, which will dissolve your (bronze?) synchros. Use RP Synchromax in the tranny, RP Max Gear in the differential. This is what RP recommends, in fact. In general never use transmission oil with sulphur in an RX-7. Usually the GL5 stuff has sulphur but the GL4 stuff (a lower standard) doesn't have sulphur. The reason is because sulphur improves the oil to meet the higher standard. That's one of the reasons I think saying Royal Purple or any thin oil doesn't protect as well as some thicker oil from a different brand is a load of bull. Being thicker will help an oil coat the gears better (just like the way honey coats better than water), but that is one of multiple factors contributing to protection.

RETed

http://www.redlineoil.com/whitePaper/13.pdf
Redline whitepaper on manual transmission fluids...


-Ted

sykminded

wow, what a discussion from such a simple question. I belive I saw a similar question before about motor oil.

What I know is that I use redline mt-90. It seems to do the job just fine, I change it every fifteen grand, and the tranny doesn't seem to be falling apart - my synchros seem fine.

So... yeah.....


damn.

I can't imagine why royal purp would be bad, but I dunno if it's as nice as redline. If you want to save a few pennies, I doubt it would be a horrible decision. A decent synthetic oil is better than cheapie-cheap organic.

ericgrau

iTrader: (1)

That Redline pdf recommends MTL in place of 75W to 85W, MT-90 in place of 90W. And it is engineered for high enough friction to engage the gears; so much for trying to use synthetics to lower friction.

Interestingly enough, that Redline pdf did go into great detail about how Redline lets you shift easier. - Just like the users reported on the various forums I read. AND it does not recommend extending oil drain intervals because, even though the oil lasts longer, metal shavings still build up just as fast. - The same forum users reported unchanged or sometimes increased grinding on Redline.

IMO Royal Purple and Neo are better than Redline for a daily-driver because users reported easier shifting AND reduced grinding. A lot of the "cheap" synthetics reduced grinding but didn't make shifting any easier. In fact, I'd reluctantly choose Mobil 1 or some other "cheap" synthetic over Redline. I'd hate the slow shifting but I'd hate the possibility of replacing my tranny early even more. Unless somebody can tell me that this grinding is nothing to worry about???

deadRX7Conv

I've used Redline in multiple RWD and FWD transmissions without issues. And, those same trannies were switched over from other fluids that weren't optimal. I find that the Neo and RoyalP fluids are not optimal in cold weather. Thicker will quiet down a tranny a little. Neo and RP are thicker then Redline easily by 20%. The thicker fluids shift slower. Because it gives the synchros more time, they seem to engage quicker and easier. The thinner Redline might actually allow you to shift quicker then the syncronizers capability. The further north you go, the more I'll recommend the use of Redline or the Amsoil gear oil. If you are in the warmer side of the country, you're probably better off with the Neo or RP. The RP is also friction modified for LSD(probably lightly). To me, that would be a less optimal fluid compared to ANY non-frictioned modified gear oil. But, the RP did shift better then the Mobil1, Valvoline, and Castrol gear oils, which are, I believe, all LSD additived and based on the older additive smelly technology that everyone is afraid of.

Shavings with a boutique oil do not buildup as fast when compared to a mineral oil. The last MT90 UOA that I saw had about 25k miles and there was no reason not to run the fluid to 50k. I've seen 10k synchromesh UOAs that looked horrible. So, those of you running Pennzoil or GM synchromesh, remove it. MTL easily trumps syncromesh.

If you have grinding, fix your transmission. Even the worst new gear oil shouldn't cause grinding. At 15-20 years old and most easily over 100k miles with pathetic maintenance, there aren't too many sound Rx-7 manual transmissions out there.

ericgrau

iTrader: (1)

deadRX7Conv: According to the info Redline released (RETed's post), half of what you wrote isn't true. As for the other half, I dunno.

deadRX7Conv

Exactly what isn't true?

ericgrau

iTrader: (1)

Read the Redline pdf file. For example:
- Redline says it improves shifting by making better use of the synchros, not by out-doing them.
- Redline says metal shavings build up just as fast with their oil as with other oils.
- Redline does not recommend extending oil drain intervals for this reason (even though the oil itself will otherwise be in better shape).

Being thinner is in fact what makes an oil shift quicker, according to Redline. But based on all the other inaccuracies I'd have to check for myself before believing Redline or RP or Neo or X is thinner. And if thicker oils quiet the tranny grinding, an oil should be able to shift quick (thin) OR "quiet" the grinding (thick), not both like RP & Neo (thick AND thin??).

tuns0ffun65

why is that so the strength of the clutch can destroy the tranny?? common sense, mr tranny keeps blowing up so ill get a stronger clutch!!!??? NEGATIVE BUDDY

tuns0ffun65

btw redline shockproof all the way in the tranny and the diff, quited down my tranny and makes shifting smoother

bacek

i use redline in my tranny and i can say it does the job..... i have no experience with royal purple but you cant go wrong with redline

ericgrau

iTrader: (1)

I should mention that Redline is wonderful stuff. I'm not ragging on Redline when I prefer another oil.

deadRX7Conv

Sorry, but I've seen UOAs of Redline gear oils compared to other gear oils and wear did not buildup at the same rate. Otherwise why the fock would you use Redline if it didn't protect better? Why use this highend PAO/POE based well additized GL4 gear oil? Why use ANY highend fluid if the wear wasn't reduced?
And, I never recommend extended oil change intervals with any fluid. But, some fluids are definitely better for those who are negligent.

Yep, being thinner and not friction modified is what makes one gear oil better then the other. I never said redline outdid the synchros. But, it is an enabler enabling the driver to do so. Some trannies are just tired. Anyone who complains about Redline MT90 shift crunching and claims that RP shifted better, has an issue. I was actually defending Redline. IMO, the thicker oil is slower to shift. That might be the reason why the thicker oil doesn't crunch. Hint, more synchro time. It was a theory. I personally have never seen RP shift faster then Redline. But, I do notice that some trannies don't like being muscled with certain fluids. You can muscle crunch any transmission with any fluid. But, the thicker fluids will require more muscle. Maybe that is why the RP or Neo crunch less. The owner ends up with a slower shift but can't actually tell or feel that it slower. And, the lack of the crunch does feel so much better.
Wake up. If your synchros are shot, and you push them too quickly, you will crunch. Try it. That thick gear oil gives that worn synchro all the time in the world to shift, by slowing the driver down just enough. Redline, might actually be too thin and increases the driver's shift speed, hence the crunch that some experience with it, which goes away with a thicker fluid like Neo or RP. This is why I recommend the thicker fluid for southern climates. Too thin and crunch crunch all the time with worn synchros. Up north, weather is overly cold. This is where Redline shines best. Its flows really well and doesn't overly slow your shifter like mineral oil or thicker oils. I've driven trucks using 250wt gear oil. And, when cold, it took two hands off the wheel and some brute force to row that shifter. But, that thing was smooth and quiet. It howled like a banshee and crunched like nuts on 90wt. Baby shifting was required. That last time I saw one of the owners, he was changing out to a 140wt to help with the cold shift issue, not enough muscle available.
So, you decide whats better, a fluid that crunches and is the fastest(thinnest), or a fluid that doesn't(because its a little thicker/slower). I know that rebuilding isn't an option for most owners which would be my 1st recommendation.

Sorry dude, taking stuff out of context and calling them inaccuracies is pretty foolish. Maybe you should more carefully read what I wrote.

And,
Where does Redline say that their fluids buildup shavings just as fast?
Where do they say that their gear oil is not recommended for extended changes?
Hows does Redline make better use of the synchros?

RETed

You stupid ****.
If you have no idea what you're talking about, don't be starting ****.
Do your homework before flying your mouth off like that, cause you look pretty stupid with your foot in your mouth.


-Ted

RETed

I'm not blasting you or anything, but I'm curious about why this is so?
Manual transmissions don't have valve bodies or hydraulic actuation, so where does the thicker = slower shifting?
Or is it just all the film strength on the gears that do it?
Pardon my ignorance on this matter.


-Ted

deadRX7Conv

Extreme example on viscosity:
Stir a cup of water. Stir a cup of honey. Which spoon can you spin faster?
The spoon is equivalent to all the moving parts, that need to work through that resistance, in your transmission.
You spend too much time in Hawaii. Spend a winter in Maine. You'd be how surprised how slow a shifter can move in the cold. The old, why is my tranny hard to shift in the cold, situation rears thick oil's ugly head every time. The thicker the fluid is, the slower you shift, as all the moving parts 'wade' through that gear oil, whether you notice it or not. That might be the reason why some experience the crunch with Redline, or with their overused sheared-thin gear oil. The oil might be too thin for a tired and worn transmission allowing the owner to shift too quickly.
Usually, if a solution is found in a fluid, then there is something mechanical that needs to be addressed.
My transmission shifts perfectly with ANY gear oil. But, I prefer the Redline because it is the best for my situation, short summers. And when it doesn't, I'll rebuild or fix it, and not look for a solution in a bottle.
Any who finds a temporary solution in the bottle, has either used the wrong fluid or has overused their fluid to begin with.

ericgrau

iTrader: (1)

Redline says the thinner oil slips in between parts easier, which lets the synchros mate up quicker.

I'm gonna let people's reading comprehension skills sort out the rest.

Or try method B: Flip a coin. They're both great oils and I won't mind if people pick the lesser one. Actually, I won't mind so much if people put bad oil in their trannies. Well, not the people who get arrogant about it anyway.

Terrh

iTrader: (7)

new trans is still working perfectly!

Only have gone about 200 miles though, and I'm staying out of the power in 5th for the most part.

tuns0ffun65

tell me exactly what you meen then by telling him to get a carbon clutch.
the only advantages of haveing a carbon clutch and high pressure pressure plate, is for the clutch to grab harder, and grabbing harder is going to increase the shock load on the transmission, therefore causing the some problem if not more problems then he had in the first place. so please dont tell me to do my ******* research, i know a little bit about what i said or i wouldnt have posted at all. just cuz i donthave 22,000 posts doenst make me a dumbass!!

drago86

I use redline 75-90NS mixed with super light weight shock proof. It is the only thing i've tried that provides a grind free normal speed 1-2 shift. My tranny was particularly bad when i bought the car though.

RETed

Carbon disc engage more progressively.
The hotter it gets - the more it grabs.
Basically, the more you slip it, the better it grabs.
Import racers have been doing this the past few years, and broken transmissions are almost totally eliminated.
The shock of all the torque is reduced.
The carbon clutch will slip initially, but the torque transfer is more mild.
Almost all the top drag Hondas run carbon clutches.

This has nothing to do with my post count.
This has everything to do with you being ignorant on the subject.


-Ted

lchaidez

iTrader: (4)

so im sorry! i read everything! and didnt see what oil was best.

which was the outcome?

redline? Oh one more thing... what about a non-turbo tranny? which oil would be best for mine? I think i posted on this thread a long time ago but forgot about it til now.

sniperstevedave

I recently changed the transmission fluid on my car. The transmission was rebuilt less than a year ago. I was having trouble downshifting to 2nd and would bounce off of 3rd unless I was granny shifting. I replaced the gear oil with Royal Purple Max Gear. I no longer have any problems with shifting or grinding.

I don't know what was in the transmission before I changed it, but it was red in color.