won't go into gear right away

[Lenny84]

i have a 2003 yukon 4x4 with 205000k . i let the motor warm up for a good 15min. Put it into reverse and nothing. rev it, still won't go into gear. put it into park. and try it again. same thing, ill leave it in reverse and about 30 seconds or so it will finely go into reverse . Now tonight i started it after work, went into reverse no problem parked for 5 min. then went to drive and off and it wouldn't go into drive. put it into park. then tried again. and went into drive no problem.

- now I've read that if i change the 4wheel drive switched in the dash it'll fix the problem . iv also read there is a sensor in the transmission that needs to be changed and that'll fix it? anyone els have this problem

 

[Z28TWITCH]

Sounds to me like a fluid issue....
I'm not a transmission guy, but Ive blown enough of em up and messed with em long enough to have a decent idea of what makes what work.
Before anything else, is it the factory unit? Maintenance schedule?
Reason I ask, is because as transmission fluid ages, just like any other oil, it loses its viscosity properties for both hot and cold. Check your fluid with the truck running for about 20 minutes. If its cold out, may want to just check the fluid on the stick after startup. Should be in the hash marks for cold. Make sure engine is running when you check it. Is it low? What color is it? Does it smell burnt?
Start there...try not to drive the truck too much....just in case.