Ok, so now that you're reading this, it's actually an M45 mounted to a B230FT in a race car. I believe the stamp on the M45 shows that it was manufactured in 80. Here's the dilemma (2 items):

It shifts from 1-2-3 no problem, but going back from 3-2, you really have to ease it in if you have the time (often making a couple of attempts, doing the double clutch thing) or jam that SOB in there and deal with the shredding noise. My guess is it is a bad synchro. Originally it was tight going from 1-2 on about half the shifts, but I've probably worn it back into shape by beating on it. Big question is if it's the synchro (easy to get) or the hub/dogs (may have some of these in ok shape from a spare gearbox, but if not -- where do I go?). Local dealers never have anything for 240's anymore.

Second issue is that it pops out of 3rd gear on deceleration. I've heard that this is either a synchro issue or a scored shaft, but don't know what to look for if the latter. This is the biggest problem because that's the gear we use the most. Checking through the archives doesn't bring up much on this latter issue.

We use the M45 because it's an intermediate solution until we get the T5 squared away and because the M45 is lighter than the M46 (and that OD is worthless for what we're doing). We need to rebuild it for a few more races because there aren't many decent M45's in junkyards. We are putting more power through it than we really should be at this point. Thanks if you can help. Cheers.