I live in the UK and have a 1990 GMC vandura 2500 conversion van with auto box, hence garages who know anything about this vechile are not that easy to find. The van is not used that often only having covered 2000 miles in the last year. The problem I have is that the gear selector will move out of park into reverse but not beyond this into drive etc. Additionally ( and I don't know if its linked) the last time I took the van out for a run the speedometer was fluctuating wildly. If I select reverse and while holding the brakes then rev the engine the speedo will fluctate upto as high as the 60mph mark. The van has been standing for three months on an incline with parking brake on and the selctor in the park position. I understand that there is a lock on the park position of the selector but could this also effect the selctor from passing through the reverse position and into drive. I couldn't find anything in my Haynes manual relating to this. Any help is much appreciated as I'm stuck in my driveway with no where to go!
Thanks in advance.
Neil Butler.