Quote:
Originally Posted by Skippy
Mention of the clutch going out would be the first clue 
You say this based on what information?
Most years, the manual called for Dexron III ATF. There were a couple of years where they speced one of the lighter weights of motor oil, but then they switched back to reccommending ATF. In addition to research on this site, I also asked the dealer what to use in my MT 240D, and they also said Dexron III. |
In the case of using an ATF in synchromeshes, IMO, I do think transmission engineers have sacrificed wear for cold weather shiftability.
Do note that high-sulfur gear lubes are incompatible with the synchronizers in many manual transmissions.
You definitely have to consider the viscosity of the fluid that the transmission was designed for. The spectrum now ranges from ATF to 75W90 viscosities and therefore a synchromesh GL4 Manual Transmission Lubricant (MTL) can be any viscosity from 7.0 cSt (ATF equivalent viscosity) to a 75W90 type viscosity of approx. 14.5 cSt, and contains special friction modification additives for synchronizer assembly engagement of brass/bronze, or steel-steel materials.
Current MTL GL4 viscosites are:
1. ATF Series - Type; 6.5 to 8.5 cSt (Equivalent ATF viscosity;
Note: ATF additive package is weak compared to most GL 4's)
2. Synchromesh Series -Type; 9.3 - 9.5 cSt (such as Amsoils MTF, Texaco's MTL, Pennzoil's Synchromesh, GM and Chrysler's Synchromesh)
3. 75W85 Series-Type; 9.8 to 11.5 cSt ( Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)
4. 75W90 Series-Type; 12.8 to 14.5 cSt (Amsoil's MTG, Redline's MT-90).
Since GM or Pennzoil Synchromesh (9.3 cSt) fluids are only about 2 cSt higher than ATF (7.5 cSt), I recommend trying it in trannies that spec ATF, since the GM or Pennzoil Synchromesh fluids have about three times the AW and EP additives, and are synthetic blends.