When I got my UK MY97, it had a high mileage and there was often a nasty crunch when going into first and sometimes 4th. 1,500 miles ago I changed the oil, using Redline Lightweight Shockproof. It's never crunched since, totally transformed driving the car
It's not cheap (£17 a litre IIRC) but it's totally worth it. I used to regularly read one of the big VW forums, and Redline oils have a very good reputation for sorting our gearbox crunches and noises.