okay so i got a 95 ls 4 door 4x4 blazer. i had tranny rebuilt becus of no 3/4 shift put it in top off tranny it reads good but still no 3/4 shift. put new tps, prndl switch but still no help i hooked to snapon scanner no codes at all and can shift 3/4 with scanner but computer wont do it on its own. so i got 2 pcms from bone yard but still no help starting to think its in the harness or a bad ground but not sure... if any one can help please all info is appreciated searched all kinds of threads and post cant find any that will help with my problem.. thank you for your time. also it is a 4l60e

 

Hopefully this will help

30 Common 4L60E Transmission Problems & Repair | Charlotte NC

 

thanks for the link but theres nothing like my problem on there

 

Ok , read your post wrong. Could be your 3/4 shift selenoid. Yuo would have to drop your tran oil pan and theres 2 solenoids, one is 1/2 and the other is the 3/4/ they are both the same part I believe just not sure which one is the 3/4. Online search will probably help

 

Easy job 1 hr the most

 

would the a/b shift selenoids work with the snap on scanner if they were bad? becuse i can cammand them with the scanner and get 3/4

 

If they work from the scan tool, they should work from the PCM. Might be an intermittent or poor connection though. Check the electrical connector on the passenger side of the transmission. Make sure all of the terminals are tight in the harness connector, and that the harness connector is fully engaged with the transmission connector.

 

will do thank you for the info

 

okay checked the all the connectors and still no luck... wondering if it could be the vss evan thow speed domitor works fine can any one tell me all the sensors that would efect the 3/4 shifts thank you

 

okay so i was wondering if not having a PCM ground fix jumper could cause a no 3/4 gear shift on my 95 blazer