[Wayne 962]

Hmmm, I doubt that switching to a new type of transmission fluid will help too much. Sounds like the grinding sounds may be caused by worn synchros. They work using friction to spin up the gears to the proper speed before engagement.

Here's what I think may be happening:

The synchros are worn on the gears. As the transmission heats up, the synchros expand due to this heat. The expansion of the synchros counter-acts the fact that the surface of the synchros are worn.

Sound reasonable? Anybody else?

For more info on synchros and how the transmission works, please see our tech article on repairing 1st gear on the 901 transmission. Also take a look at our 914 parts diagrams for exploded views of the synchros.

Hope this helps,

Wayne