Engine/Transmission (1998.5 - 2002) wont go into 3rd gear under throttle pressure

[WatsonJ]

Adjusted the bands and installed the APPS noise isolator from Genos last month to cure the 45-50 mph trans lock up and the unlock issue.
Towed my boat to Laughlin from Phoenix last week with no issues. While there, the trans started to resist going into 3rd gear unless I was off the throttle.
Got it home by going very easy on the throttle and letting the cruise control do the work. Adjusted the APPS to .495 per from .463 per the white tag.
No codes ever thrown. Still have the same problem. Fluid level is fine and looks and smells good. Trans running 150 -160 degrees while towing.
I can manually shift thru all gears with the column shifter. Any suggestions?

Thanks in advance.
Jwats
PHX

 

[WatsonJ]

P01622 code

Adjusted the bands and installed the APPS noise isolator from Genos last month to cure the 45-50 mph trans lock up and the unlock issue.
Towed my boat to Laughlin from Phoenix last week with no issues. While there, the trans started to resist going into 3rd gear unless I was off the throttle.
Got it home by going very easy on the throttle and letting the cruise control do the work. Adjusted the APPS to .495 per from .463 per the white tag.
No codes ever thrown. Still have the same problem. Fluid level is fine and looks and smells good. Trans running 150 -160 degrees while towing.
I can manually shift thru all gears with the column shifter. Any suggestions?

Thanks in advance.
Jwats
PHX

rechecked the APPS today and it was down to .387 (huh) was able to readjust to .450 only. (could go over .510 yesterday.) it also finally threw a code while I was working. P01622. (low voltage at the APPS) I'm getting 5.05 at the blue/white wire. Also noticed the throttle cable was very frayed when I moved the
plastic ferrel on the cable. It did not seem to bind but I replaced it anyway. (did the APPS reset procedure) Also re checked the front band. The APPS moves from .450 to 3.78 volts at WOT. what next? new TIMBO APPS. or Governor pressure transducer & solenoid? trans shifts good on very light throttle pressure but
otherwise does not want to go from 2nd to 3rd. Has only 156,000 miles. light towing (less than 5000 lbs infrequently)