My 2000 vw passat 1.9 TDI manual grinding gears

Assuming you have a manual transmission, it seems the synchronizer rings for third gear are worn. To correct, transmission must be rebuilt or replaced.

the synchros are not DIY, when they start to go it will grind when the RPMs are higher like getting on a highway, you can try double clutching and see if that helps.

Great to hear. Good Job!

1,change the oil - original vw is light brown ( NOT red )
-reprogram the throttle body
- adapting the kick down position

blowen gasket?
fuel filter full o ****
injector failure due to build up
need oil change due to sludge in pan

try changing the oil, paying great attention to manufacturer's recommendations. Could be oil is way too thick and is sticking things that are supposed to slide, until it warms and thins.

have some gear oil change, it may ease up your gearing. hope this helps

I have the same problem with my 2001 volkswagen cabrio, but I know the solution.
You need a new clutch, or it will continue to slip.
If you cannot afford the clutch. You can "baby" the clutch by easing the clutch out, and eventually it will catch. (It should catch in a second or two.)

throw out bearing

hi if its just second to thrid then the clutch is slipping on thrid gear look at the boxes oil level is important but look at the colour is it red and tranperant as this is ok if its brown its a sign of the clutches slipping i would try a stall test on thrid gear first and if its ok second gear [manually] see is the engine stalls at the correct rpm if you thinkabout it imagine you are in thrid gear in a manuual box and suddenly drop into second it would be hard shifting it could also be a faulty thrid gear solenoid yates210456