Truck just started acting up. When on drive it does not shift. I can manually drive in first and second, not third. And the speedometer quit working as well. Buddy thought it was the shift selonoids so changed those still nothing. Any ideas?

 

It would help if you fill out your profile so we know what truck/trans you have.

 

Possible busted sprag in the forward sprag assembly. Do you have Reverse? What vehicle, engine and trans?

 

I’m currently experiencing the same thing. Truck drives fine in reverse, 5.3-4L60e. All gauges work except speedo, new VSS installed, checked all fuses

 

Im new to the forum and a first time suburban owner. It's a 1999 k2500. One day the speedometer quit working. And I noticed reverse gear seemed to be slipping. The next day, no reverse gear at all. I've replaced the transmission output sensor. Crickets. I noticed a couple ground straps had rusted in 2. I replaced them, no luck. And now I've noticed I don't have low gear. I have D, 3rd, and 2nd. It's a 4L80-e transmission. And wisdom will be greatly appreciated. You don't realize how much u need reverse until u don't have it. Lol