97 sierra 3500 speedo/shifting problem
 

Hello guys
I have a 1997 gmc sierra 3500/454/4l80e. It has started shifting erratically and also has not been indicating speed correctly. torque converter lock up is cycling. I changed trans filter/change fluid. Scanned for codes, no powertrain codes up. I jacked up truck and ran up to speed speedometer still not indicating correctly. I put DVM on transfer casespeed switch and it appeared to read correctly
ac voltage increased with wheel speed about 600 mv@ 45 mph. I have nothing to compare that to,also my manual shows two VSS, one also on transmission but the component I think is it has different color wiring . Anyone know what /where that sensor is? thanks in advance Cort

RE: 97 sierra 3500 speedo/shifting problem
 

well I replaced both vss and still no fix. no codes up but still ****ting all over the place and speedo still not right. I am thinking PCM any ideas ...any one. Come on throw something out there thanks cort

RE: 97 sierra 3500 speedo/shifting problem
 

try posting in the chevy silverado area, there are more guys that browse over there

RE: 97 sierra 3500 speedo/shifting problem
 

thank you !