Thickest Mercon ATF?

[metroplex]

I have a Tremec TR-3650 that has exhibited some issues with the blocker ring jamming up for first gear. According to others with the same transmission, this is "normal". This transmission has been used for over 6-7 years in the market and has been plagued with some of the same problems.

The manufacturer claims that synthetic ATFs like Mobil 1 ATF are "too slick" for the synchros and blocker rings to catch, and they recommend non-synth Texaco / Havoline Mercon ATF. Some people claim that Royal Purple Synchromax works great, others said it doesn't make a difference, while others claim GM Synchromesh / Pennzoil Synchromesh worked great. The Tr-3650 uses "composite blocker rings" and paper-lined synchros, so gear oil is out of the question.

I suspect it could be a matter of the viscosity of the ATF when it is cold and at operating temperature. Does anyone know what the thickest Mercon-spec ATF is, or perhaps could recommend a solution? I would prefer a full synthetic for a longer lifespan in hot environments.

 

[TallPaul]

I believe the Redline High Temperature ATF is Mercon rated and 10 cSt. Typical Mercon would be around 7.5 cSt. You can also call Dave (the chemist at Redline) and ask about the slickness and syncros concerns.

 

[TallPaul]

You might also be able to run something like Redline's MTL at 10.6 cSt.

 

[unDummy]

RP Synchromax is an excellent ATF replacement.
PZL Synchromesh is ~9cst.
Amsoil MTF and Redline MTL would be excellent choices.

Redline has two 10cst ATFs. You could also blend the ATFs to make a fluid at whatever visc you want.

Any of the full synthetic TES295 and Type-F ATF's should be considered.

BTW, no fluid will make up for poor engineering. Quality fluid, along with maintenance intervals, should help with delaying those problems. But, when they occur, tear it down for the rebuild and upgrade where possible.

 

[metroplex]

Tremec requires Mercon ATF for the TR-3650, and MTL / MTF don't meet the spec. Redline's High-Temp ATF appears to be the equivalent to MTL in terms of viscosity (5W-30) but also happens to meet Mercon ATF spec. I believe Mercon is important because the TR-3650 uses composite blocker rings and paper-lined synchros.

 

[TallPaul]

Paper-lined synchros? Sounds like a Fram filter.

Seriously, I never heard of such a thing. It doesn't sound that good to me.

Anyway, High Temp ATF is Mercon. Mix with D4 Mercon ATF to get just the viscosity you want.

 

[metroplex]

Ford has been using the TR-3650 in the Mustang GT since 2001 (and in the 2001 Cobra), and it was used in the BA Falcon in Australia. It's a 5-speed manual and almost everyone has had problems with the gearbox. Tremec claims that non-synth works better because it isn't as "slick". Some claim that GM Synchromesh works nicely but others state that the ATF is required due to the composition of the components used in the TR-3650. If High-Temp ATF doesn't improve things, I may just go to Mobil 1 ATF, and worst case, to non-synth Mercon ATF.

 

[mechtech2]

Don't a lot of enthusiasts with these trannys use Pennzoil Synchromesh?
I've heard that it works great, but has to be changed every year or so - more often with HARD track use. The wonderful shifting fades after a while.

 

[metroplex]

My guess is that the friction modifiers or additives in the Synchromesh fluid probably wear out due to heat.

 

[gtx510]

My Mustang T-5 liked MTL, I'm sure your Tremec will like it too. (is a Tremec a Mexican made top-loader w/ a 5th gear?)

Amsoil MTF or RP Synchromax should also work well.

 

[metroplex]

Tremec's are usually made in Mexico except for some of the T-56s which were made by Borg Warner. My TR-3650 is actually a remote-shifted trans. The 01-04 TR-3650s were top-loaders, while the 05-up TR-3650s are remote shifted. All of them are 5-speeds and rated for 360 ft-lb of torque but people claim they are good for up to 500 hp.