Transmission Selector slips from D into N

[svdsinner]

My '98 2500 5.9L V-8 Gas has developed a weird issue:
While driving, the transmission selector will sporadically slip from the D position back into N. (Which of course puts the truck into neutral and requires me to move it back to D to continue driving it.) It's currently happening every couple miles when hitting normal minor road bumps. I can rest my hand on the selector arm and that slight downward force is enough to keep it from slipping back to N. Conversely, I barely need to touch the selector to get it to pop from D to N. The detent that holds it in position seems very weak. Nothing I have seen indicates that the problem is in anything else except the selector. (IOW, I don't think the transmission itself is causing this, just the selector arm mechanism on the steering column.)

I've tried fiddling with the selector arm, tapping it in various directions to attempt to get it to solidly lock into D, but a couple miles later, it pops out again.

Is this a known/common issue? It there something I can service to fix this? Maybe a spring on a detent pin or something?

 

[Gr8bawana]

Sounds like the linkage needs a little adjustment.

 

[ouch1011]

Can you feel a definite gear position when you're moving the selector through the gears, or does it just seem to glide from park to low gears? There is a detent and spring inside the transmission that defines the gear positions, so if there is no definition to the position of each gear, you may need to pull the trans pan off and have a look.

 

[svdsinner]

There definitely is a functional detent. However, it's weaker than it should be. When I pull the pan, what/where am I looking for the detent mechanism? Luckily, I've got to pull the pan for some other maintenance, so I just needs to know where the mechanism is.

 

[cat199]

I think this is the location of the detent ball.