Trouble Shifting into Reverse

I have a 2003 TDI jetta. Recently I am having trouble shifting mostly into reverse. The clutch feels ok. I have manipulated the gears from under the hood by moving the linkage, and sometimes feels a little stiff. I have a feeling that the problem is inside the tranny. Anyone have any thoughts or checks that could be performed? If I had to replace the tranny, any cost estimate? The car has less than 300km and runs good. I believe the tranny oil is concealed and there is no way to check the level.
thanks
fmrfred

U can check fluid by removing the fill plug. Just like checking a differential.

Check the linkage and the linkage bushing. Have been down this road and it wasn't the tranny or clutch

Check to see if the plastic bushing on the pivot ball for the shifter has broken. When you get the boot up, the ball has a thumb with a bushing that controls the reverse gate. If the bushing fails or is badly worn, the required travel isn't met and the gate doesn't open for reverse. I'm working on mine now. It's a simple and fairly quick changeout for the shifter lever IF you can get the car high enough to get under it. I need to gain another 6" under the car to do mine.......