Volkswagen, like most German manufacturers, does not like you messing with their stuff -- unless "you" are a factory mechanic. Here in America, we tend to see the notion of Volkswagens with "sealed transmissions" and BMWs without oil dipsticks as a bit of chicanery meant to send basic maintenance dollars back to dealerships, or outright insulting. And it is, both. But, then again, we gauche Yanks have never had a problem enduring the indignity of working on our own cars -- especially when it means depriving a Stealership of money for something we can easily do ourselves.
Drive the Jetta for 10 minutes or so to warm up the transmission fluid. Stop the car on level ground where you intend to work, and place your foot on the brake. Shift the shifter into each gear and hold it there for three to four seconds. Place the transmission in Park.
If you have access to a lift or a friend with a lift, then use it to raise the car from the ground. Otherwise, you'll need to use a floor jack to lift all four corners and secure them on jack stands. It's critical that the car remain level.
Locate the transmission and the two plugs. On the low right-hand side -- passenger side -- of the transmission you'll see the drain plug. On the front, upper left-hand corner you'll see the fill-check plug. Remove the fill-check plug first with a wrench; if the transmission fluid is up to level, a small amount will trickle out. Next, place a drain pan under the drain plug and remove the plug. Allow the fluid to drain.
Install a new drain plug and snug it down to about 22 foot-pounds with a torque wrench. The gasket on these plugs are single-use only; if you reinstall the old gasket, it will almost certainly leak. Use a hand oil pump, with one tube in fresh tranny fluid and the other in the check-fill hole, to refill the transmission with fluid. It's impossible to overfill -- just stop when fluid starts to trickle out of the check-fill hole.
Install a new fill plug and snug it down similarly. Lower the car, start it and run the shifter through all the gear with your foot on the brake, pausing for about five seconds in each gear.
