I own a 2001 Chev Blazer V6 4.3Litre 4x4 Automatic. It will not select 1st gear. If put into 2nd gear and pull away, move lever to 3rd and drive, I must move lever back to 2nd.

Diagnostic test showed a fault [shift solenoid] Po758 [b] Electrical is causing gearbox shifting problems.


Based on the diagnostic, I have replaced the Neutral Safety Switch which has made no difference.

Has anyone experienced the same problems/know what the problem could be?

Thanks

 

Yep I have the same issue with my 93. Though I'm still reserching it. I been tracing wires but really just been taking my time. The shift solonoids are located inside the trans pan and I'm probablygonna replace them I was just checking other stuff first. Those things are 50$ a piece and no promise they are gonna fix anything. Since its a offroad truck 1st gear is really all I need. Ill let you know if I find anything but I might not mess with it for like a week

 

See if you have something called the TCC, Torque Converter Clutch. On our '93's we have this on the 4L60E transmission. This solenoid is the one that applies the fluid to the correct solenoid, 1st or 2cd...3rd or 4th in order for the transmission to shift. It also exhausts the fluid from the applied solenoid at the correct time in order for the transmission to shift to another gear. If this unit goes bad you will only have 2 gears, which ever one's were 'on' when the TCC went. It gets the information from the RPM, fluid temp, fluid pressure, coolant temp and speed sensors which is something else you might want to take a look at. If a speed sensor is wrong it will want to keep shifiting to an up or down gear...hope this helps a little...don't even know if you got one in your 2001...lol

 

i ended up fixing my junk, but probably not the way you want. its possible my tcc might be bad cause i know it gets its power from the ign/gauge fuse and that fuse blew the same day i had my issue. replacing the fuse didnt fix the problem. the problem i found was that the pcm is losing ground going to the solenoids it shows 12v ground with the key in the on position but soon as i start it and put it in gear it goes down to like 1v... could it be because the tcc is bad and thats where the ground goes through? not quite sure. i dont need that stupid thing either, truck only goes 10mph tops

anyways since my truck is just a turd offroad truck and i only need 1st i grounded both solenoids manually and my truck now has first gear.