B5 gearbox problems, Help!!

[AFCpaul89]

Hi there, not been on site for a while, just need to ask a quick question, my mate is going to look at a 1999 (T reg) 1.9tdi sport estate with 74,000 miles on the clock for £370 but the auto box isnt changing gear. It will change in manual.
Does anyone know if this would be an easy fix or not worth the bother?

Thanks for reading.