What Makes Synchromesh Fluid Work So Well ?

[mitote]

Originally Posted By: JSRT4
..I wonder what applications would use added FM fluid, perhaps ones with limited slip diffs or something ?


You can't think of FM's as existing only in the world of differentials.

I've read a few threads where Mr Kule has discussed friction modifiers and their versatility

MolaKule:

"Friction modifiers for differentials does not equal the same friction modifiers for IC engines; friction modifiers for IC engines doesn't equal the same friction modifiers for ATF's; friction modifiers for ATF's does not equal the same friction modifiers for manual transmissions."

"Remember, a friction modifier can be a friction reducer, a friction increaser, or one that controls friction in a specified manner"

 

[MolaKule]

The Pennzoil Synchromesh has the same viscosity and operational specifications as the GM non-FM, but has a different formulation.

If your mt calls for a 75W90, I would not use a lighter viscosity fluid such as the Synchromesh. That recommendation was for trannies that use ATF's.

I do not know what the difference might be betwee the FM-modified and non FM modified synchromeshes.

 

[MolaKule]

Quote:
Is the GM fluid synthetic or partly so?


It's a synthetic blend.

 

[sprintman]

Now I don't know what to use. Molakule do Speciality Formulations make a suitable replacement for BMW lifetime fill?

 

[MolaKule]

Sorry, we have not been operating for over a year.

 

[JSRT4]

Originally Posted By: sprintman
Now I don't know what to use. Molakule do Speciality Formulations make a suitable replacement for BMW lifetime fill?


Doesn't the BMW lifetime fill have a viscosity similar to ATF ?. If so the GM Synchromesh would be a good choice IMO, slightly thicker viscosity, but not overly thick. Semi-synthetic fluid shouldn't harm any components of the tranny ( I know many BMW owners are fearful of Redline fluids due to internet rumours circulating about Redline being damaging to tranny bushings or some garbage like that). The added viscosity and added ep additives gotta be better for the tranny than the stock fluid IMO. I would recommend changing the fluid on a more regular basis as well, the are several UOA examples on this website to prove that lifetime fills are figments of manufacturers' imaginations. There isn't anything onerous or expensive about swapping 3 quarts of manual tranny fluid once per year IMO.

 

[cosynthetics]

The problems with Redline are with seals not bushings.

For the bimmer, try Royal Purple SyncroMax.

 

[sprintman]

I was going to use Redline say 50/50 D$ATF and MTL. Is the seal problem a myth?

 

[sprintman]

That's D4ATF not D$ATF

 

[cosynthetics]

Originally Posted By: sprintman
Is the seal problem a myth?


Depends on who you ask. I've read it first hand on some BMW forums. May have just been random.

 

[double vanos]

I have used MTL in my 330ci practically since new. The car now has 104k miles on it and it shifts better than new, has no noise or slop and cold weather makes no difference in shifting (but then again I'm in Houston). The car has never leaked a drop of oil, period.

I like MTL so much I am currently using in my '08 Mazdaspeed 3 in place of the really bad cold weather shifting 75w90 oil it came equipped with.

This is clearly a case of a thinner fluid than spec'd but I'll be da mned if I'm going to put up with the famous 1-2 upshift grind that these cars are noted for.

The MTL has cleared all that up nicely and just to hedge my bets I'll probably do a UOA in about 15k miles to see whats happening. I'll be back with the new in about a year! Cheers! DV

 

[sprintman]

1-2 upshift grind in the BM or Mazda?

 

[gamefoo21]

Just so people know... In the Metros, Sprints, Fireflys, and Swift 5 speed gear boxes, the manual calls for 75w90 GL4. This leads to early syncro failure in colder climates.

There was a service bulletin for these cars to switch to Synchromesh oil. Another bulletin and change was for the dropping of 10w30 as the specified oil in these cars to 5w30 since our climate caused all sorts of failures.

Just so you know.

 

[double vanos]

1-2 upshift grind in the BM or Mazda?

In the Mazda. The BMW has been smooth as silk all it's life.

The 1-2 upshift grind is well documented at mazdas247.com. The fluid is just too thick.

Might try some 75w/90 thinned with GM synchromesh just to see what happens. Cheers all!

 

[sprintman]

Thanks. I'm going with 50/50 MTL and D4ATF and see how it goes. Gets cold here in Canberra in winter.

 

[Craig in Canada]

Originally Posted By: sprintman
Thanks. I'm going with 50/50 MTL and D4ATF and see how it goes. Gets cold here in Canberra in winter.


IIRC my winters are colder than yours and MTL was fine in my ZF 5-speed. I forget if you're Getrag or ZF. I don't consider D4ATF and MTL to be from the same "line" of fluids like MTL and MT-90 are so I also personally wouldn't go blending them willy-nilly on my own.

 

[sprintman]

Hmmm maybe straight MTL then and see how it goes. I can always wait till it warms a little. Temperature gets to maybe -5/6C here in winter unless I go to the alps where it can be -12C

 

[4wheels]

Has anyone done an oil analysis on GM Synchromesh to see what it's makeup is?

Does anyone know how GM Synchromesh compares with another "new" GM fluid for Manual Trans (GM PN 888 61 800 Manual Transmission & Transfer Case Fluid)?

 

[sprintman]

Went with straight MTL. Very good when warmed up.

 

[cheetahdriver]

i have started recommending Motorcraft Full Synthetic Manual Transmission Fluid, Part # XTM5QS, for the miata transmissions. it is 75w-90, GL4, german, synthetic, has FM, meets Ford lifetime fill, and is expensive. what more could you ask for?

it is made by fuchs for ford, but it doesn't seem like it matches any of the fuchs labeled products. i have gotten some good reports off of it on the miata forums.

i haven't, however, tried it myself. i am running SF in my miata (Molakule's Special Sauce), and it shifts so good it is sensual. i am deathly afraid of screwing that up if i changed fluids, since i can't get anymore SF at any price (anyone got a cache they want to sell?).