can this 1988 Jetta 5 speed transmission be fixed? Or better to replace?

[bcatt]

reverse and first gear are gone. 2nd and 3rd gear work. I suspect that 4th and 5th gear are also gone, but I haven't tested them. Symptoms prior to losing those gears:

- reverse and first were sometimes difficult to shift into (resistance in the shift lever)

- sometimes when shifting into 5th, would go into 3rd instead

- twice, when attempting to back out of a parking space, the transmission would not respond, but after some shifting around of the lever into different gears then putting it back into reverse, I would hear a bang (sounded like I hit something) then the gear would engage and seem to work fine.

- when it finally went, I was in the process of backing up, heard the loud bang, and car stopped reversing, shift lever became very loose, as though in neutral when in gear. Reverse and 1st position give me 3rd gear (and I suspect 5th would give me 3rd as well), and goes into 2nd (I suspect that 4th position would give me 2nd gear).

So, what I am wondering is if this just needs some parts or if I will have to replace the whole transmission? If it's just parts, which parts, and can anyone provide some good schematic illustrations of the transmission?

TIA