1997 GMC Yukon 5.7L, Intermittent problem where speedometer will stop working and transmission will not shift out of 1st when in Drive. will shift from 1 to 2 manually but not into 3.

SOURCE: 1993 Chevy Silverado

Replace the vehicle speed sensor, it's located in the tailhousing of the transfercase

SOURCE: transmission not shifting

Sounds like a speedo gear in the transmission ... I think the tahoe one had a speedo cable the speed sensor is located in the speedo ... will cause all those to fail if speedo is not working as did in my Astrovan

SOURCE: transmission wil not shift out of 1st gear and

you need to take this to dealer for repairs,there might be a short in the speed sensor wires that did that to your speedometer,the reason it won't shift is speed sensor,input sensor or output sensor on transmission.

SOURCE: 1997 transmission Slow Acceleration

not sure if this is the answer yet but i have the same problem with the same codes i work at an auto parts store and a few of the techs that are customers have lead me in the direction of changing the ignition switch, i am doing it today will let you know if it solves the problem

SOURCE: My 2001 GMC duramax with

Thanks for choosing FixYa and welcome to the site. The first thing you need to do is check your transmission fluid. Make sure it is at the correct level. You may need to change the fluid and change the filter. If you haven't did this, I would advise you to do it. You would be surprised to see the difference, if that is the cause. It is very hard to diagnose a transmission problem because there is no way to find out other then taking it apart. It could be damged teeth, seal, ect. It is possible that you have a bad torque converter. But the only way to know for sure is looking at it or having a mechanic look at it. Now, the transmission should throw a fault code. If your check engine light is on, this may be the reason why. If so, you need to take it to Autozone or Advanced and have the codes read. It may tell what is wrong. If there is no check engine light, it is possible that you may just need a fluid change. I would change the filter and fluid first. Transmission maintenance can be very expensive. Shifting can become hard if there is low fluid or you need a new filter. Pay attention to the housing and see if it is leaking any fluid. This could be a sign of a bad seal. The transmission also has sensors that can fail. If the fluid change doesn't help, your only option is taking it off yourself or haing a mechanic do it for you. This is just one of those things that you need a hands on experience to know the exact cause of your problem.