Picked up a used replacement 2nd gear for my t2t4 trans, do the dog teeth on this gear look too worn for use or will I be ok with a new synchro and some filing?

 

You need to get the matching mainshaft and countershaft first gear. New synchro, new selector sleeve, no file. Filing should only be done as a last resort.

 

Thanks, I got the matching 1st gear and input shaft to go with the replacement gear. I just replaced the shift collar, when I got the transmission 2nd gear wouldn’t engage even on the bench. Tore it down, replaced the shift collar with a mint one, now it shifts but scratches and pops out. Here’s what the current 2nd gear and synchro look like

 

It's not in great shape (the "new" one) but definitely better than the old. I'd keep the old set as a spare for future use since its discontinued.

 

the "new" gear is in better condition than almost all my gears lol