I have a 1998 Chevrolet Silverado 4x4 with 100k miles. When I start up there are no warning lights on dash. Put in drive and when I get up to about 10 miles any hour the ABS light comes on. It will go in 2nd but that's it, no 3rd or 4th. If I stop cut truck off and manually shift up and down sometimes light will go off and will work fine. Until I go to drive again. Checked fluid and no burnt smell and good level. Heard might be ignition switch, and tap on it when happens and know change. I feel like it is electrical problem but don't know where to start.
Would greatly appreciate any advice.

 

Welcome to the forum. I moved this to the Silverado section so more people would see it.