4L80E Electrical ? 2nd gear only :(....

[DIYORPAY]

Back a couple years ago this intermittent problem started occuring. When i started the truck to go to work i would take off and sometimes it wouldn't shift out of 2nd gear. But if i would stop and put in park and shut off ignition and restart it, it would always shift normally after that. At that time the truck got driven every day. (95 in sig) After about a month and a half of sitting with no use.......... i was gonna go put my snowplow on and it wouldn't shift again. I tried the old trick of shutting off and restarting but it doesn't work anymore. Any suggestions??? Trans fluid and filter has been changed religiously...........no other problems for years other than this.
---Brian

 

[Mike L.]

Scan it for codes is the first thing to do.

 

[docdray]

2nd gear only possabilities---definately need codes.

code 24 -tranny output speed sensor--input speed3k rpm, output 200 rpm for for 1.5 sec.
53 -system voltage high--voltage above 19.5v for 2 min--
75 -system voltage low--system voltage below 6.7v, higher 10.5v 81 qdm and 2-3 solenoid--pcm senses wrong voltage on 2-3 solenoid circuit ---solenoid off is voltage high and on is voltage low-off in 1st nad 2nd, on in 3rd and 4th

front or rear vss good? 900 to 2000 ohms
1-2 (pins e and a)and 2-3 (pins e and b) solenoid 20-40 ohms
list of other conditions for no 3rd, however check vss and 2-3 solenoid first along with wiring harness.