[winders]

Originally Posted by Old H2S

I tried Swepco, very good stuff, I liked the Amsoil synchromesh better, then I found this,
https://www.amazon.com/gp/product/B000NUES82/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&th=1
Genuine Ford Fluid XT-M5-QS Full Synthetic Manual Transmission Fluid -
Silly price but it is a game changer on my 915 with 300k on it.

Well, you might like how it feels but you're not going to like what it does to your synchros. The synchros are balk ring style and nothing like the cone system used on modern manual gearboxes. The baulk ring setup does not do well with synthetic oils...but you go right ahead.