Originally Posted by Fast68
What transmission oil are you running?
If your using a fully synthetic I can see that causing problems with the synchro rings or adding to an existing problem with them..........."
I can appreciate that people want to use the oil Ford specified back in the day. But I can testify that all the issues one hears about as a result of using a GL-5 synthetic, or a synthetic engine oil, are greatly overblown. And the benefit of greatly reduced friction when going synthetic is a huge plus, that cannot be overstated. I drive my classic cars in the real world, not in a laboratory. In a lab there is always an issue with a stray electron that left it's orbit and went astray. The sky is falling the sky is falling and our synchro rings have lost their way, or some such BS.
In my little corner of the real world I drive the pi** out of my machines because thats what makes me grin. I use all synthetic oil products, the engine oil, transmission & rear end lubes, etc. They work just fine, if they didn't, or if I had ANY measurable wear in the engine of transmission, I'd drop them in a flash.