Well, looking through the inspection covers on the TKO third gear is shredded. I'm not sure on the status of the counter shaft yet. I am planning on disassembling and inspecting the whole thing this weekend.

After a cursory search of the internet, I can get 3rd gears pretty easily. I am having a hard time finding counter shafts in stock, hopefully it's not broken - although I can't think of a situation where the gear is broken and the counter shaft isn't.

Apparently, this is a common failure mode for TKOs/3550s and there's quite a bit of speculation on what causes it. There are claims that two of the gears on the counter shaft are too close together, which they changed in the latest redesign of the box. Maybe the shafts spread too much under load reducing tooth engagement. My theory is that it's not really designed for the fully reversed loading we get in road racing. It's also possible that the stiff setup in the #50 has some affect on trans life.

I'm curious what other Mustang folks are running, and what their experience is. I'm considering switching back to a T5 (A-5 or some other variant) just because I can get them easily and carry a spare. Wrecking a transmission at COTA or Hallett and not having a spare would be a huge bummer. I can scrounge for parts to fix the TKO or send it off to a trans shop. I suppose I could get another box - but that's cost prohibitive (> $2,500).

Thoughts?
- Josh