91 GTi just lost 5th gear!?!

[Blutarski]

My 91 Gti (1.8L Manual 5spd trans)which was only supposed to get me through last winter was survived until last night. Not exactly the worst $400 spend on a car with 234000miles. I gat an additional 10k out of it, but...
While driving, shifted to what was 5th gear and now only produces a sound of plastic gear on gear sound and there is no power to the wheels. It has been making a whine in 5th so I just assumed that the gear is toast. Can anyone help define what this toast is? It's a backup beater car so I most likeley won't rebuild it unless it's something really simple and cheap to fix, but I may just keep driving it until it stops alltogether...?...
In unrelated news, it's also blown out the gasket between the manifold and down pipes to the cat. Any hot tips on this one (by hot tips, I mean not speding the 250 on a new downpipe and bolts and gasket)
Thanks

[veedubmechanic]

On the linkage for the transmission on the transmission there is some plastic linkage parts. A long metal one with black ends and 2 small white plastic ones. Usually they break and leave you w.o 5'th gear. There about 4.00 each at the dealer.

Also 5th gear is a common issue with older 020 transmissions. There are adjusting shims that move the gear over to make up slack in the linkage ect... But your better off spending 100.00 at the junk yard for a junker trans than taking the 5th gear assembly off and adding shims..