So, heres what Ill say to that. While many DO have success doing it, Im sure my donor car had success because it still ran and drove fine, right up until the passenger side was reduced to about 1ft width.
With that said, the bearings looked pretty similar to this:
Had the bearings failed? No, not yet. Would they have failed? Maybe, maybe not. It could have taken another 50-100k before they did (for the record, the car had 103k on it when it was totaled). But the blue bands tells me that they were entirely too hot at some point in their life, probably for quite a while. And the balls were significantly blued as well.
The 5 and 6 speeds are similar internally from what I understand. I cant say because Ive only opened (manually or, uh, otherwise
) the 5MT boxes. Id say the answer applies to both though, since manual transmissions, save for a few examples, are fundamentally the same.
Also, anecdotally I know, but every time I have been flat towed in the racecar, Ive had wheel bearing issues shortly thereafter. The fronts on the Miata are notoriously weak for road racing, and I understand that a normal road car is lucky to see 1/4 of the punishment I dish out in a weekend, but I feel like its worth throwing out there. I use blueprinted hubs (even though Mazda says theyre not rebuildable) and keep good notes.