Mercron 5 is designed for automatic transmissions not manuals.
The synchromesh fluid that GM and Chrysler uses performs much better and maintains its vicosity better than than auto trans fluid does which helps protect better.
Hock please do some research. When the ford t-5 first come out, the factory spec fluid was mercon dexron 3. Since then mercon5 has come out with better friction modifiers. If you dont believe me call your local ford dealership or transmission shop. I know it says on the bottle (for automatic transmission) but its the right stuff for this transmission. TRUST ME i know what im talking about here, and no im not saying you cant use other stuff. Im just saying this is the recommended fluid.
Here are some other fluids that could be used:
Pennzoil® Synchromesh Fluid
Pennzoil® Synchromesh Fluid is a synchromesh transmission fluid designed for certain manual transaxles and manual transmissions used by General Motors or Chrysler. Pennzoil® Synchromesh Fluid is formulated with high quality paraffinic base stocks, a fluidity modifier, multifunctional performance additives, corrosion inhibitors, a foam suppressor and a shear stable viscosity index improver additive. It provides excellent oxidation stability, low temperature performance, excellent synchronizer performance and compatibility with yellow metals, such as bronze, brass and copper components found in manual transaxles and transmissions. This product will satisfactorily lubricate General Motors or Chrysler manual transaxles and transmissions from -40°C to +150°C.
Benefits:
* Exhibits excellent low temperature performance
* Meets GM Specification 9985648 and Chrylser Specification MS-9224
* Suitable for use in GM manual transaxles and transmissions requiring GM Part No. 12345349 or 12345577
* Suitable for use in Chrylser transaxles and transmissions requiring Part No. 4874464
* Excellent synchronizer performance
* Excellent yellow metal compatibility
Redline D4 ATF (T-5 Trans Fluid)
Our most popular and versatile ATF, D4 is suitable for use where Dexron III, Dexron II, or Mercon fluids are recommended. D4 ATF is a fully-synthetic product designed to satisfy the improved low-temperature requirements which will be in the new Dexron IV specification, and the improved shear-stability requirements which will be part of the new Mercon specifications.
D4 ATF also provides a GL-4 level of gear protection, making it a superior product for transmissions and transaxles like the Corvette's T-56. The balanced frictional characteristics provide smooth and consistent shifts for extended drain intervals. The superior stability compared to petroleum ATFs allows high-temperature operation without varnishing valves and clutches which leads to transmission failure. It’s stability allows high-temperature operation without varnishing valves and clutches. Also provides improved shifting in cold weather. t-5 trans fluid