I'm looking at a 99 Vanden Plas with the transmission stuck in one of the gears. Now the owner believes it is the transmission sensor that needs replacing, does that sound right for something like this? I had a 95 XJ6 that wouldn't get out of park and was told it need a sensor. The car is for dirt cheap so Im not too worried if I loose money on it I would just like to see if anyone else has had a problem like this?

 

What is stuck - the shifter, if so where...?

 

No the transmission itself. It will go into park, reverse and drive but only into forth gear or so. My 95 had its shifter stuck in park.

 

Having only 4th gear is 'limp home mode'. What you appear to be saying is that the transmission shifts but only 4th gear is available in D.

That is probably due to failure of the A drum, a common problem with the 5HP24 transmission. It must be rebuilt or replaced. If replaced with a used transmission the same could happen again.