Reverse gear failures and noise in the manual transmission models are common.Google+
Car Problem Reports
Volkswagen Jetta TDI Reverse Gear Failures and Noise in Manual Transmission Models are Common
Volkswagen Jetta TDI Problem
Average Mileage: 154,875 mi (95,000 mi - 250,000 mi)
Visitor, 2004 Volkswagen Jetta TDI, 203,000 mi
Rattle noise in trani when I release the clutch pedal. It's not the throw out bearing but sounds just like it
Trouble shifting into gears without a good throw. Seems hydraulic related in regards to clutch. New car for me so owner may have worn out clutch as well. I will diagnose and see what comes of this issue. I see people have mostly reverse issues. I notice that when in neutral, if I apply an additional stomp on the clutch or a harder depression, the hydraulics will activate stronger and make shifting easier. Will look into transmission fluid... it is about time for that to be replaced but I don't think it would result in issues like this. This came about when the weather declined in temperature up here in the Northeast (adding to hydraulic suspicions).
Visitor, 2004 Volkswagen Jetta TDI, 148,000 mi
My car works in the forward gears just fine, but about 8 months ago, it started hesitating before going into reverse. Sometimes it would take as much as a couple of minutes. I have not fixed it because the local dealership wants $5000 to replace the transmission. The car now has 152,000 miles on it and it goes in reverse fine when it is warmed up and not at all cold. I have to always park where I can pull forward. The mechanic said the transmission fluid was "burned" and that meant the transmission would have to be replaced or rebuilt.
I have another 2004 VW Jetta TDI with 265,000 miles on it. That one is still going strong with no issues.
Visitor, 1998 Volkswagen Jetta TDI, 160,000 mi
reverse grinds and pops out
Visitor, 2006 Volkswagen Jetta TDI, 100,000 mi
reverse gear knocks
Visitor, 2004 Volkswagen Jetta TDI, 157,000 mi
first trans oil change done at 135000. Vw mechanic at dealer in fl. said not to service at 100000 better to let run till it died.Felt wrong so took it to dealer in tn.serviced ran fine then one day reverse started not engageing then after about 1k miles it stopped working at all.VW now has 225000 miles still waiting for other shoe to drop.Runs fine in forward,just no reverse.Every VW i have owned in the united states has had transmission problems.done with VW!!!
Visitor, 1999 Volkswagen Jetta TDI, 250,000 mi
reverse failure, and loud noise from engine