I beg to differ.
Type F fluids DO have friction modifiers in them, albeit not at the same level or of the same type as the higher friction modified fluids such as the Dex/Mercs, or the Chrysler ATF+ series.
The chemistry of ATF friction modifiers and MTF friction modifiers are totally different.
You need a specific friction modifier chemistry for the synchronizer assemblies in the MTF.
In addition, the Anti-Wear chemistry in MTL's is about 3 to 4 times highers than in ATF formulations.
The major reason many manufacturers specify a fluid such as DexronIII or thereabouts in many Manual Transmissions is because of two reasons:
1) ATF shifts better in cold weather than the fluids they originally specified, which were about 10 cSt@100C fluids,
2) At the time there were no MTL fluids of the same viscosity as ATF, but there are now.
In addition, ATF fluids will not protect as well as application specific MTLS because the AW additive package in ATF's have only 1/2 to 1/3 of a GL-4 protection rating.
ATF fluids DO NOT have the specialized friction modifier chemistry nededed for MT synchronizers.
Below are fluids suitable for MTL's that specify ATF:
Quote:
A. The four MTL fluids closest to a Kinematic Viscosity of 6.1 (About the same viscosity as a DexronVI) or so are:
1. Castrol Syntrans FE 75W,
2. BMW (Pentosin) MTF-LT-3,
3. Honda MTII or MTF 2.
4. Ford FML-XT-11-QDC
B. The next higher viscosity MTL would be the 7.5 cSt versions (About the same viscosity as a DexronIII)
1. Royal Purple's Synchromax
2. Ravenol MTF-2
3. Honda MTF
4. VW part number G052512A2
5. GM Manual Transmission and Transfer Case Fluid
6. BMW (Pentosin MTF 2) MTF-LT-1, 2