W108 Gearbox Fluid
 

Hi, I am going to change the gearbox fluid on my 1969 280S with a 4 speed manual gearbox for the first time. It has the later side cover G76/27 box.

Question: Am I reading this right that I put ATF in it? It’s a new one on me! Thanks all!

Yup, ATF type "F", for early model Fords ('60's and '70's).

I'd read that as Dexron since Type F is generally specified as such.

Type F has a higher friction coefficient than Dexron so it works with the metallic clutch plates in a Ford auto trans.

In a manual trans, the synchronizers are generally cone shaped clutches that bring each gear to the same speed as the shaft. On a trans that is worn, too slippery of a fluid can cause the syncro to slip and gears to grind. Moving to type F might help this type of situation.

Thicker oil can help a worn trans by causing more drag. ATF is about a 5 weight so moving to a motor oil can help, some brands of cars did spec motor oil so this isn't something new.

Thanks, the previous owner just wrote the word Castrol in his records. The gearbox has 270k miles total, about 66k since it was rebuilt.