RP Synchromax wrong MTF for my Civic?

[bryceban]

I put Royal Purple Synchromax in my 02 Honda Civic w/ 5 speed manual trans about 25,000 miles ago(6 months) because I was needing an oil change and wanted to do both at same time. So while I was at O'reilly Auto Parts I decided to pick up some MTF and the guy recommended the RP Synchromax. Well I went to RP's website yesterday and used their cross reference chart and to my surprise it said to use their RP 10w40 or 5w30 motor oil for Honda/Acura trans. No mention of the synchromax for my application........

So my question is....is this the correct fluid? It did not improve the shifting characteristics at all. I've been thinking of getting some Amsoil Synchromesh 5w30 manual trans fluid to replace it with. Is there any difference? Will I hurt my trans with the RP?

Don't want to change it out if it doesn't matter but need some advice please.

Thanks

 

[unDummy]

Its the correct fluid. The lastest replacement Honda MTF is thin like ATF. Earlier Honda MT choices were 30 and 40 weights.

As long as shift quality is great, and level is correct, keep driving on the RP SynchroMax. Change it out in 30k.

 

[dparm]

75w90 gear oil is pretty close to 5w30 or 10w30 motor oil. Only real difference is the additive packs.

 

[OriginalRocket]

You are fine with that stuff. One of the best MTFs for hondas I find is GM synchromesh friction modified. Check any civic enthusiast forum. I've had it in my Integra for 30k, and I've had rp stuff and this latest fill is Honda MTF. The only really big difference is Honda mtf smells like a thousand cats took a [censored] in the same spot fermented for a few days in humid hot air.

The Honda mtf and GM stuff shift a tiny bit smoother in spirited driving.

 

[bryceban]

Good to hear, didn't want to mess with changing it out so early. My Honda owners manual recommends changing the MTF every 120,000 miles/6 years for normal conditions. I will probably change it at around 60-80k miles since 99% of my driving is hwy cruising in OD doing at least 40-50 miles every time the engine is cranked...

Edit: So why does RP recommend their motor oil offerings over their Synchromax in Honda/Acura manual transmissions?

 

[unDummy]

Originally Posted By: dparm
75w90 gear oil is pretty close to 5w30 or 10w30 motor oil. Only real difference is the additive packs.


No it isn't. 75w90 is 30-50% thicker than 5w30 or 10w30. 75w90 is closer to a 10w or 15w-40 oil.

Originally Posted By: bryceban
So why does RP recommend their motor oil offerings over their Synchromax in Honda/Acura manual transmissions?


Before Honda-MTF, their MT's were filled with 10w30 or 10w40 motor oil.

 

[bryceban]

SO I'm starting to think I'm just wasting money paying $13-16 per quart of RP MTF when I can effectively just use a good 10w30 or 10w40 synthetic motor oil? Which would be better, 10w30 or 10w40?

 

[OriginalRocket]

No, if you read the manual it says motor oil can be used if MTF cannot be found, but the next change (at severe interval) must be MTF. It's the additives that you need. My 01 calls for 30k miles between changes and 15k for severe.

 

[Bror Jace]

bryceban, the add-pack in motor oil isn't friction-modified for compatibility with synchronizers. Expect fair-to-poor shift quality and reduced synchro life.

It will work ... but should only be seen as an interim fill ... unless the car is already at the end of its life.

I use Amsoil MTF in my '06 ... and wouldn't use anything else anymore.

 

[Bror Jace]

Oh, and for a decent viscosity chart, please see:

http://i229.photobucket.com/albums/ee149/BrorJace/Miscellaneous/viscositychart3.gif

 

[bryceban]

Ok, thanks for the responses guys. I'll stick to MTF specific lubes. I may go with the Amsoil offering next time. I can get it shipped to me for about the same price as I can buy RP locally.

 

[unDummy]

New motor oils(after API SJ) can't be used. The addition of friction modifiers for MPG and as an AW will make the synchro's function poorly.

If you're stuck on a motor oil, stick with motorcycle oil because some have wet clutches, and the oil doesn't have the MPG improving FM's that can cause wet-clutch slippage.

There are plenty of MTL and MTF's now that can be used. Stick with them. If RP is too expensive, price around for other brands. Amsoil, Redline, BG, Torco, Pennzoil, Nissan, GM, Honda, Wynns... have great MT lubes.

I could care less what the owners manual recommends. 30k or 3yrs, whichever comes 1st, is what I recommend for change intervals. Anymore is abusive and negligent. If you plan on dumping the car soon, then don't bother with any MT changes. If you want to keep it a long time, then maintain it. Since your driving style is highway only, stretch it to 50k/3yrs.

Your transmission breathes as it heats up and cools down. Because of this, it can take in moisture on rainy days, and dust/dirt too on dry days, and is why I put a time limit.
Slow leaks may not be noticed, along with normal fluid evaporation, which could lead to running low or out of fluid. If you don't want to change it, top it off, when cold, a once or twice year.

There is no MT filter. The wear can compound wear and continually builds up. Don't fall for the extended intervals that ANY automaker recommends.

 

[bryceban]

Good points and well taken, thanks. I think 50K miles or in my case yearly, is a great plan. Heck, it's actually pretty easy and only takes about 1.5 qts. Yes, I plan on keeping car until it completely gives up the ghost. Car is paid for and sees 800+ miles a week. I am really hoping to hang .5 million miles(or more) on motor and trans without tearing into...