Many many moons ago, my buddy Paul gave me this gearbox in exchange for some help on his Mark II (to be clear, he’s an innocent party here). That’s a genuine XJ6 gearbox, and I was going to use it as the centerpiece to convert my own car to a manual. But, and this is what life is now like for me (alas, alack, etc.), BAC Rusty (who sold it to Paul) had created a special lightweight version which might just be too hot for this car.

I decided to take the box apart to inspect it…the gearbox part is pretty good, it seems, with decent syncromesh and what-not. But when I disassembled the overdrive, I found that it was a special lightweight version. Here is the overdrive unit partially disassembled:

When you lift off the piece on the chunk to the right, underneath is supposed to be a planetary gear assembly, like this one:

(courtesy of, or should I say “borrowed” from, The improvement I found in its place:

Welp. In case it’s not clear, the entire planetary gear assembly is gone, and instead, there is a lot of brazing on the roller hub assembly, which has the effect of locking the overdrive solid.

This incredible bit of engineering has pretty much put paid to the idea of converting this car…so, thanks, Rusty! BAC will always hold a special place in my memory, and this is a perfectly fitting final purchase from that fine establishment.