Engine/Transmission (1998.5 - 2002) '01 DTT won't shift, where to look next?

[Devil Black Diesel]

All, my truck randomly won't shift out of first gear. I have to pull over, shift in and out of nuetral, and eventually it will shift into 2nd. The problem is getting worse and worse, and I've notice when coming to a stop it won't downshift to 2nd/1st sometimes either.



Both Governor solenoids have been recently replaced as suggested by others. I also just installed a new TIMBO APPS in last night and the problem still exists... where do I look next?



Some say i might have a loose wire? If yes, when I get underneath the hood tomorrow which wires to I look at/trace from the computer to the trans?



The truck has both the ATS fix and a DTT noise filter installed to deal with the TC lock/unlock issue.



Is there some basic troubleshooting I can do with a multimeter on some of these wires that might be causing the problem?



Codes are:

0622

1765

1693

1740

1757



Any ideas?

 

[fox]

Go for the speed sensor on the bottom of the Overdrive section.

 

[Devil Black Diesel]

I'm pretty sure the speed sensor was changed along with the Governor Solenoids but I'll change it again since it's so cheap.



Will a bad speed sensor cause my symptoms?



Anything else to look for?



Thanks

 

[DavidC]

When I have used a ohmmeter on a bad sensor it would show open, a good sensor would show 600 ohms.



Dave