What is the problem of my opel vectra, does not shift at reverse?

Strange transmission problem on a '99 Oldsmobile Intrigue?

• I have a '99 Oldsmobile Intrigue with the 3.5L engine, and automatic transmission. I had my transmission rebuilt two years ago at around 88,000 miles. Now recently it has been having a strange problem shifting into reverse. It doesn't have a problem every time I shift into reverse, only about half the time. If it doesn't shift into reverse I can put on the gas a little and the car won't move, but if I take my foot off the gas and try again, the car will slowly move backwards. I usually have this problem when parallel parking. I can go into reverse to get into the parking spot, but if I need to shift into reverse a second time almost always it will cause the above problem. Then the next time I shift into reverse when leaving my driveway (after I got home and usually have had it parked over night) it will shift hard into reverse, but will drive in reverse perfectly fine. There are no strange noises. I have checked my fluid level, and it is fine. The color is a dark red, and does not smell burnt. Does anyone know what could be causing this? I will take it into a shop to have it fixed, but I would like to know some likely causes so I know where to point the mechanic.

• Answer:

  Its not clicking into gear! Let the guy who fix it take a look at it!