hey guys me again. my 89 K5 recently started shifting noticibly late or prolonged, but only when i first start driving it. as i drive it starts to shift normal again usually after going through all the gears a few times or after i get off the highway. any ideas what it could be? someone mentioned the vss to me but i thought it only worked the speedometer.

 

Your transmission is not electronically controlled. I would suspect a TV cable adjustment may be necessary.

 

thanks for the help.

 

I had another truck that gave me the same problem (years ago). Root cause was a failing torque converter.

 

Check for a vacume leak to tranny or just loss of vacume in general.