So i bought my truck in January and it needed a clutch so i replaced it and the slave cylinder. I was having issues driving it because it really didn't wanna shift and i was almost to the point of buying a new tranny cause i knew the synchros were going out. But i decide to do something no else has said on here and it worked. I had already put brand new tranny fluid in ATF and that didnt help. So i bought GM synchromesh and let me tell ya it fixed my tranny 100%. before it would grind every once in a while if i wasn't careful how i shifted now this thing is like butter. Honestly it was 70 bucks just for 3 quarts but so worth it. A new rebuilt tranny is 1000 bucks so i did well i think.

 

What is the viscosity of the syncromax? Is it thin like ATF? Ford specs ATF because regular gear oil is too thick to sling up into the top of the gear box and get into the tighter tolerance areas in the syncros and bearings. Just helped my brother in law rebuild a manual trans in his ranger because the previous owner put gear oil in it because he said it shifted smoother but the trans was ruined from it. It burned up a few of the bearings and a couple syncro's.

 

I don't know but I it made mine shift and it wouldn't shift before it wasn't that thick .. A little thicker but it's made for synchro s ATF isn't designed for synchro s which I think it's a pore design on ford

 

what was the weight on it? i have a feeling that stuff is gear oil and that is a big no no on a ford manual trans..the M5OD-R1 isnt a smooth shifting transmission to begin with anyway