Sounds like a internal transmission failure, look for a good mom and pop transmission shop
When a Mercedes C280 will not move in forward or reverse it is an indication that the transmission is going out or has already gone out in the car. This is true of all cars, not just a Mercedes.
Could be a pump problem or broken planetary. Regardless, the transmission will need to be disassembled.
Another problem might be the sun gear drive shell in your auto transmission. GM 4L60 transmissions are notorious for this problem causing a no reverse symptom. this means that you will need some serious work done on your vehicle
Could be cable or linkage out of adjustment. Verify from underneath is actually in drive before you do anything else (with a helper)
It could be the transmission, it could be some parts under the vehicle that rub only when travelling forward.
When a Toyota 4Runner will not move in reverse, it could be that the reverse band in the transmission is broken. Another possibility is a problem with a range selector. Both problems would need the services of a transmission expert because the transmission would have to be pulled.
A car that won't move when in reverse could indicate a problem with the transmission. It could also indicate a problem in the gear selector.
If the car does this every time, but is ok in forward gears, then the transmission could have an internal problem. There could also be an electronic issue. If possible, run the computer codes for any bad codes to appear.
IF it is a rear wheel drive vehicle it mabe something wrong with the gears in your final drive...
This is a internal problem, I had same thing wrong and I replaced all I could then brought it to shop and he said the bands are slipping
Could be a linkage problem..
Check the GEO Trackers transmission fluid. The fluid could be low, or the fluid could show metal parts indicating a transmission problem causing the noise.