Transmission Problem

[Alan Fry <afry@shrike.depaul.edu>]

I have a 1986 Audi GT coupe.  The car has a fairly new clutch, slave
cylinder, and master cylinder (all done by previous owner), and 125K miles.
I haven't detected any leaks underneath the car.  The transmission is giving
me problems. In gears 1 through 4, it seems that in general, if I rev the
engine above 3000 - 4000 RPM, it doesn't want to let me shift into the next
gear.  If I try and force it, the gears grind.  For example, if I redline it
in first gear, I have to shift to third or fourth, unless I try and match
revs perfectly.  This hasn't really caused me any problems other than
preventing me from accelerating very quickly and being annoying, because I
rarely rev the engine that high anyway. However, today the problem seemed
worse.  At times, it didn't want to shift even below 3000 RPM (it was the
coldest it's been since I've owned the car, having bought it this summer, if
that means anything) The only thing that occurs to me is that the syncros
are gone, but I wouldn't think all of them would be gone in a car with 125K
(I've only owned it for the past 5 or 6K).  Being a college student, I'd
rather not have to replace/rebuild the transmission, because of the expense,
but I will if I have no other options.  Can anyone think of other (cheaper)
things to look at?  Also, I have found a good used transmission for a good
price.  How many hours of labor would you estimate that the average repair
shop would charge for the replacement?  Thanks.
-Alan Fry
-86 Audi Coupe GT