Manual Trans. Spec'd for Mercon V, what to use?

Messages
35,785
Location
NY
Use what Ford Specs. Castrol makes Mercon V, as well as several other companies. I've been using ATF in my M5OD tranny since 1987, no problems at all.
 
Messages
4,651
Location
The Garden State
I had a 1989 F150 with the MOD5 tranny. I shifted fine with the factory Mercon. My 2002 F150 with the same tranny shifted horribly with Mercon. It was better with Schaeffer's 204 ATF, but not good. With both the shifting was ok in freezing temps until the fluid heated up. When warm it crunched & grinded, more so with the Mercon. I ended up trying RP Synchomax MT fluid. It's way better, not perfect but way better. From what I've read here and other sources a correct viscosity dedicated MT fluid is better for the manual tranny than ATF. It has the additives needed that ATF does not have for a manual tranny. Whimsey
 
Messages
5,069
Location
Saratoga, NY
"I ended up trying RP Synchomax MT fluid. It's way better, not perfect but way better. From what I've read here and other sources a correct viscosity dedicated MT fluid is better for the manual tranny than ATF. It has the additives needed that ATF does not have for a manual tranny." Whimsey speaketh the truth. Try these ATF-thin (cSt 7.5 - 8.3) manual transmission fluids as direct replacement of ATF: Royal Purple Syncromax Honda MTF II Torco MTF Others such as the GM, Chrysler and Pennzoil syncromesh fluids may work as well ... but are a bit thicker (cSt 9.5 or so) with Red Line MTL and Amsoil MTF thicker still.
 
Messages
19,479
Location
Chicago Area
Others such as the GM, Chrysler and Pennzoil syncromesh fluids may work as well ... but are a bit thicker (cSt 9.5 or so) with Red Line MTL and Amsoil MTF thicker still. This is what I'd use. I lean towards the full synth Redline and Amsoil, but he Penn Synch dino is very good.
 
Messages
2,008
Location
grande prairie AB
I use mobil multi vehicle atf cause it is certified for mercon v and all older versions of mercon in my 94 with the mazda 5 speed. it calls for mercon so its good to go. Shifts really good with the fluid. a little firm when cold but not to bad.
 
Last edited:

MolaKule

Staff member
Messages
21,947
Location
Iowegia - USA
I would recommend a 50/50 mix of Redline Lightweight ATF with Redline MTL 70W80. This mix will give you a MerconV viscosity with the added benefit of the special friction modifiers needed for smoother synchro assembly operation, and increased levels of anti-wear agents.
 
Last edited:
Messages
180
Location
Ponchatoula, La.
I tried the Mobil 1 ATF in mine and noticed no difference. I went with Amsiol MTF 5W30 and it still really did not feel a lot different till I had about 10,000mi. It seems to be loosening up now and not as notchy.(15,000mi.)
 

Maritime Storm

Thread starter
Messages
421
Location
New Brunswick, Canada
Had an interesting coversation with the local transmission rebuilder, he suggested a synthetic 5W30 motor oil. Mine shifts great when cold, but gets notchy to the point of annoying when warmed up. The rebuilder suggested 5W30 figuring the fluid may be too thin for the application. Thoughts? I have MerconV and 5W40 Syntec kicking around, would may'be going half & half be better?
 
Messages
4,379
Location
MS
Originally Posted By: MolaKule
I would recommend a 50/50 mix of Redline Lightweight ATF with Redline MTL 70W80.
I've been thinking about something like this for a while, I think this will be my next T45 fill.
 
Messages
9,614
Location
Pennsylbammyvania
Originally Posted By: MolaKule
I would recommend a 50/50 mix of Redline Lightweight ATF with Redline MTL 70W80. This mix will give you a MerconV viscosity with the added benefit of the special friction modifiers needed for smoother synchro assembly operation, and increased levels of anti-wear agents.
Mola; Would this work for a Tremec T56 which specs a Dex 3 type fluid as well, or should I mix their D4 with their MTL instead???
 
Messages
6,180
Location
Texas Hill Country
I used a Mobil1 product that met Mercon V specs, I noticed no difference in shifting quality over factory fluid. Honestly just stick with regular Mercon V. I was hoping for better shifting in the dead cold of winter until the gearbox warmed up, but not even Mobil 1 could help that.
 
Messages
9,614
Location
Pennsylbammyvania
Originally Posted By: Bror Jace
Others such as the GM, Chrysler and Pennzoil syncromesh fluids may work as well ... but are a bit thicker (cSt 9.5 or so) with Red Line MTL and Amsoil MTF thicker still.
Except that the Amsoil MTF is actually thinner than the RL MTL (by exactly 1.0 cSt), and about even with (or slightly thinner than) everything else you've mentioned above, and only ~2.O CST thicker than most Dex 3 spec ATFs, both synthetic and mineral (one of the reasons I am trying it out straight, unmixed, my itself this winter season wink ). It also has a VERY high VI compared to most else out there.
 
Messages
1,855
Location
Australia
Don't know if it's available in the US but Castrol Australia has a version of their Syntrans MTF that's [email protected]*C for the 6 speed T56 Tremec in the Falcon XR6 Turbo. It's also recommend for the Tremec g/boxes used by Holden(GM) http://www.tds.castrol.com.au/pdf%5C5707_SyntransB_117956_200703.pdf
 
Top