I have a NV 3550 in my new Jeep Wrangler. This is a very noisy transmission, so I changed the OEM fluid to RP Synchromax, which was a big diference, quieter and easier to shift. But now that the new Amsoil MTF is out I don't know wich one will work better. It seems the Amsoil has a higher viscosity than the RP. Of course I can't find either one of this fluids in Mexico, so I have to wait until a friend or myself goes to the USA, so it's a big issue for me to change it. I'm planning on keeping this Jeep forever, so I guess my question is: Is there a big difference between this two fluids?
RP Synchromax or Amsoil MTF?
- Thread starter Rubiconjeeper
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Rubi, what's that box call for? What weight?
It's always best to stick close to the factory weight recommendation ... then pick the best fluid in that range.
I would only use something like RP Syncromax if your transmission called for an ATF ... and even then, Specialty Formulations has a better choice in that thinnest of weights.
--- Bror Jace
It's always best to stick close to the factory weight recommendation ... then pick the best fluid in that range.
I would only use something like RP Syncromax if your transmission called for an ATF ... and even then, Specialty Formulations has a better choice in that thinnest of weights.
--- Bror Jace
MolaKule
Staff member
If I were running in Mexico I'd use our MTL-P.
As 02SpecV said, Synchromax is too low a viscosity to run in that transmission.
As 02SpecV said, Synchromax is too low a viscosity to run in that transmission.
Bror: This transmission uses synchromesh from factory which is supposed to be a 5-30 fluid for synchromesh transmissions, so RP Synchromax is a prefered choice, but then again, is Amsoil better?
If the transmission calls for 5w30 - Amsoil MTF will work great.
MolaKule
Staff member
RubiconJeeper,
As Bror asked, what year, engine and what is the speced viscosity in cSt@100 C for the MT fluid?
A "synchromesh" fluid can mean any fluid for a manual transmission that uses synchronizer assemblies for engagement of gears. And these fluids can range from ATF, 20 weight viscosities to 75W90, 40 weight viscosites.
5W30 can mean a large viscosity spread. A 30 weight fluid infers the top end could be anywhere from around 9.5 cSt to 12.8 cSt. Our MTL-P has an average 100 C viscosity of 11.5 cSt which puts it square in the middle of the 30 weight category.
The original Synchromesh manual transmission (with a capitol "S") fluid from GM had an average viscosity of 9.2 cSt,
RP SynchroMax has a viscosity of 7.0 cSt,
and
SynchroGlide from Specialty Formulations has a viscosity of 9.5 cSt,
Amsoils specs shows an average viscosity of 9.6 cSt, according to:
http://www.amsoil.com/StoreFront/mtf.aspx
I'll let you decide which products are closer to the GM spec.
RP Synchromax (according to my information) is closer to an ATF's viscosity which infers from their specs that this is a 0W20 weight.
Also keep in mind that in very hot climates, you may want to go one weight notch higher.
As Bror asked, what year, engine and what is the speced viscosity in cSt@100 C for the MT fluid?
A "synchromesh" fluid can mean any fluid for a manual transmission that uses synchronizer assemblies for engagement of gears. And these fluids can range from ATF, 20 weight viscosities to 75W90, 40 weight viscosites.
5W30 can mean a large viscosity spread. A 30 weight fluid infers the top end could be anywhere from around 9.5 cSt to 12.8 cSt. Our MTL-P has an average 100 C viscosity of 11.5 cSt which puts it square in the middle of the 30 weight category.
The original Synchromesh manual transmission (with a capitol "S") fluid from GM had an average viscosity of 9.2 cSt,
RP SynchroMax has a viscosity of 7.0 cSt,
and
SynchroGlide from Specialty Formulations has a viscosity of 9.5 cSt,
Amsoils specs shows an average viscosity of 9.6 cSt, according to:
http://www.amsoil.com/StoreFront/mtf.aspx
I'll let you decide which products are closer to the GM spec.
RP Synchromax (according to my information) is closer to an ATF's viscosity which infers from their specs that this is a 0W20 weight.
Also keep in mind that in very hot climates, you may want to go one weight notch higher.
Go with the one that is cheapest and has the lowest shpping costs!
MolaKule
Staff member
But that doesn't guarantee value or quality.
All of these high end transmission fluids are top quality. Having said this,I personally would buy the one that is the cheapest that is "suitable" for my cars needs. I agree,shipping costs obviously have nothing to do with quality. I used to use Redline 5w20 oil,but I simply could not justify the extremely high product/shipping price for MY needs. To each his own.
synchromax is intended to replace atf fluids, it is thinner than synchromesh fluids, given that I would go with the Amsoil mtf, it is a better match viscosity wise. The RP is too thin IMO.
Thank you all. I gues I'll go with Amsoil MTF, but for the moment I'll have to wait until I'm able to bring it from the USA. Meanwhile, is there a way to increase the viscosity of the RP?
I've never had much luck mixing transmission fluids, it doesn't seem to mix as well as say engine oil brews, something about the friction modifiers likely makes it harder to get good mixes. I'd just wait until you can get some Amsoil over there, but there are lots of synchromesh type fluids available on the market that you could use to hold you over until Amsoil arrives.
You won't be sorry..great stuff in my TJ's NV3550!
MolaKule
Staff member
The thread starter discussed synchromesh fluids and I was simply attempting to clarify what synchromesh fluids were (in a general sense) and provide information on alternatives as well.
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