quote:
Originally posted by MolaKule:
All transmissions with composite or brass synchromesh assemblies have some type of friction modifier built into the fluid to modify the synchro engagement characteristics.
Jeeps generally require one of two fluids; a fluid of 75W85 or 9.0 to 11 cSt (our SynchroGlide or MTL-P) or the more heavy duty trannies require the 75W90 fluids such as our MTL-P.
The NV3550's generally require a 75W85 fluid (MTL-P), and the 1500's require a GL such as our MTL-R, a 75W90.
According to my check-chart, the NV3500's require a fluid similar to our SynchroGlide (below the Mason-Dixon line) or the MTFGlide (above the Yankee line).
I must admit to being thoroughly confused now.
So, I'm going to stick with the GM#12377916 because it says right on the bottle that it's intended for the NVG1500 transmission which I have in my Jeep.
The following might provide some additional insight. I don't know how old it is but suspect at least a couple of years.
"Synchromesh transmission fluid is designed for certain manual transaxles and transmission used by General Motors and Chrysler corporations. It provides excellent oxidation stability, low temperature performance, excellent synchronizer performance and superior compatibility with yellow metals such as bronze, brass and copper components found in manual transaxles and transmissions. Synchromesh fluid is specifically formulated for transmissions used by General Motors and may be identified by GM part No. 12345349. This product also replaces GM part No. 12345577 used in Top Load four-speed manual transmission applications. Likewise, for Dodge truck applications, Synchromesh fluid is identified under Chrysler part No. 4874464.
Synchromesh fluid was developed for use in the NV (New Venture) 3500 five-speed manual transmission used by both Chrysler and General Motors. This is the only product recommended for applications using the NV3500 Transmissions after 1991. Between 1988 and 1991 either Synchromesh or 5W-30 engine oil was acceptable in the NV3500.
Both automakers also use the NV1500 manual transmission, which also requires the Synchromesh fluid. However, the NV1500 transmission requires additional friction modifier to achieve proper performance and protection. General Motors part No.12377916 already has the friction modifier added. On the other hand, Dodge applications using the NV1500 require Chrysler part No.4874464, which does not have the additional friction modifier added. Therefore, an additional 0.2 pint (0.1 liter) of friction modifier must be added to Chrysler part No. 4874464. The friction modifier may be purchased at your local Dodge dealer.
Don Johnson (Don Johnson is the author of the above-parenthesis are mine for clarity. SpitIX) is the vice president of Product Engineering at Pennzoil Products Co. He is a member of the API Lubricants Committee. He is a member of the Society Of Engineers (SAE) and the Society of Tribologists and Lubricant Engineers (STLE). Readers may write to him at: P.O. Box 2967, Houston, TX 77252-2967
Thanks.