I'm guessing this is common, but it's pretty easy to shift the truck into "Drive" without it actually locking into Drive (where the shifter actually pops back toward the dash). I let my wife test drive the truck for the first time (it belonged to her father, who passed in 2006), and we nearly joined him on the other side when she gave it some gas to cross opposing traffic, and the damn thing popped out of Drive.....any easy solutions??? I'd like to stay 6 feet "above" ground for a while longer, if you get my meaning!!!! thx, Mike

 

This is not a common problem. I would try adjusting the shift linkage first as this will probably solve the problem.

Inside the tranny there is a spring and a detent ball that engage the manual lever assembly. If the spring breaks the shifter can move around on its own. There are two ways to check this. You can feel it without opening the tranny if you have the experience to know what it should feel like or you can drop the valve body.

 

You can loosen the linkage form underneath with truck in Park. Reach on top of shifter at tranny and make sure it is all the way back into the detent. Then tighten it back up. Now form the cab, make sure it stops firmly at each detent stop. Then verify that it will only start while in Park or Neutral. If the indiactor on then dash is off, that is another adjustment.