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Manual Transmission Fluid

Car Talk Guys…

A question on lubricants that maybe you can answer.

I have a 2003 Ford Ranger pickup, with a manual transmission. Approaching 60K miles, I noticed that the owners manual recommended changing the transmission fluid. It also specifies “Motorcraft MERCON ATF” fluid. There is also a warning that the “MERCON ATF” and the “MERCON V” (for automatic transmissions) are not interchangeable.

So it is off to the local Ford dealer to get “Motorcraft MERCON ATF”. But the parts guy says that they no longer make ATF, and that I need to use MERCON V. He checks his books, and seems convinced.

A visit to the Ford website does not provide any solid information. A trip to the local Advance Auto store, and their computer says to use the automatic transmission fluid.

As I recall, the automatic transmission fluid has a much lower viscosity than the manual fluid, so I’m surprised at the change.

So, my question is… “What’s happening with manual transmission fluid?”

ATF or ATF like fluids have been used for quite a while in manual trans.

When you are using your “As I recall” abilities what years are you refering to?

I remember in manual trans VW’s we used manual trans fluid (not 90W diff. fluid) but that was in the 60’s early 70’s.

This is a change that some manufacturers started many years ago. I have no idea why, but I was first introduced to this when I owned a 1979 Plymouth Volare manual trans, and it required Dexron as a refill.

You need to remember that Dexron III and Mercon are the same, and a multipurpose ATF such as the one Advance sells meets your requirement. Not so sure that MERCON V is substitutable for MERCON, but since Dexron III/MERCON is readily available, I wouldn’t use MERCON V.

Here’s the Pennzoil ATF page:
It backs up what Jayhawk said.

Ford stopped making Mercon so you can use and aftermarket Mercon or use what Ford recommends. You should be able to find the Ford recommendation yourself by surfing around at I find no reason you should doubt the Ford parts guy on this.

Aw heck, here is what you probably need:

P.S. I don’t see any reason that you should not go with the aftermarket Mercon since it is probably less expensive. The changes in Mercon V are really address automatic transmissions.

I am just an old country boy living in the city for 57 years have done all my mechanical work and I would not change the transmission oil. I will last as long as the motor will.

I have been doing my own mechanical work for 60 years and I would not change the trans oil, it will last as long as the engine.

I’ve seen several failures of transmissions all caused by people NOT changing their transmission fluid regulary. Now if your manual transmission uses gear oil…it can probably last the life of the engine…but if it uses ATF…thus so thin…I’d change it according to the recommended interval change.