Reply to "Minimum Synchro Clearance etc. etc. etc."

When you load it (squeeze the gears together)the gear assembly should freeze or at least drag heavily.

Where the cone shape presses on the gear is where the synchro action takes place.
They work like drum brakes.

What happens is that they wear together and eventually polish each other so that they become too slick.

Chances are when you pull the cluster apart you won't SEE a problem other than the cone on the gears look polished. That's where you are loosing the braking action of the synchro because of lack of friction between the two mating surfaces.

You can not roughen them up. It doesn't work that way.

Second gear is the worst because it is the largest gear in the cluster and is harder to slow down.

The shift gate through second is also used the most and is also the narrowest.

I'm not sure if the flats can be machined to give you more travel or if you can tighten them up by changing the thrust washer.
I don't think so.

The original Pantera ZF uses iron blocking rings/synchros were as the GT40 was brass and lasted longer.

Butfoy, the last I talked to him, had brass synchros made and if I recall correctly were $900 each. I forget. I could be wrong. It was some time ago I talked to him.

He gets $5000 to go through the unit PLUS parts.
There isn't anything in a ZF that is unusual if you have worked on manual transmissions before.
The clusters are all made the same way and disassemble similarly.

The difference is in the cost of the parts.
You can't even get the parts from ZF for these. Butfoy is the only one that has them.

By comparison, blocking rings/synchros for a T10 are less that $20 each.

Sometimes readjusting the shift linkage can fix the issue. Sometimes not. The shaft naturally has twist in it and I think over time looses some of it's temper and gets TOO flexable. Also check the trunion shaft support on the chassis. The bracket can bend and the trunion itself wears out and lets the shaft move enough to cause issues like this that you tend to blame on the synchros.

You can try double clutching second gear, i.e., clutch to move out of second gear into neutral, then clutch again to go into gear. This is how you would shift a transmission without synchros.

I think RBT also has a one or two year waiting period as well. Might as well do the entire thing yourself.

Ask Ron in Maryland. He's done a lot of them himself. Maybe he can help?

I've also found that contrary to RBT recommendations that synthetic MTL (manual transmission lube) tightens up the transmission and adds a friction modifier for the synchros and helps a lot to rejuvenate them.

It swells the seals and gaskets and does not cause leaks.