Hello...My 1993 s-10 blazer 4x4 was shifting just fine and now will only shift manually.....I changed fluid and filter and it is no better...I have changed egr,knock sensor ,plugs,wires,cap,rotor,....please help.....anything I can try...vacuum lines appear intact...thanks also already changed spider

 

try the VSS. vehicle speed sensor. my 93's vss isnt hooked up due to swapping transfercases and thats how mine is, doesnt shift but you can manually do it

 

check and make sure the trans fuse has voltage. dont know what trans u have

 

Thank you for helping me...I will locate the speed sensor and change that....also I will re-post when I figure out what transmission i have....You guys are GREAT.....also I will locate fuse and see about checking voltage