Automatic transmission questions

[HotRodr56]

Hi, truck is a '94 C3500 dually, 7.4 gas engine, 4L80E ?? transmission. Just fixed a fast idle problem I was having with the TBI and everything was right again. I then noticed while driving the truck that the trans would not always shift into 3rd gear if I ran the shifter in 3rd. I could bump it up to OD and it would shift fine. This does not happen all the time but has gotten to be 70% of the time. I don't mind using OD but I don't want to pull a load this way so I do some research about TV cables and how to adjust them. I figure I might have something out of adjustment after working on the TBI. Some sources say it is a simple procedure and should actually be done every 6 months to allow for cable stretch while others say don't touch it - it was set at the factory by voodoo and black magic and is not for mere mortals to tamper with. Others indicate the need for a pressure gauge to check line pressures as you drive. I go to look at the cable for some reference and it turns out there isn't one! There is not even a sign of one being on the truck ever.
I research the RPO codes and get MT1 which is the 4L80E and MXO which is MERCHANDISED TRANS AUTO PROVISIONS, O/D - What is that? I look at the trans, count 17 pan bolts, study the pan shape - it looks like a 4L80E except mine has a raised area in the bottom with a drain( I assume ) plug. Is this normal? My real question besides what I have been rambling on about is: Do 4L80E transmissions use a TV cable and if so where does it enter the transmission? Is this a normal setup for a 94 truck? I checked the fluid and it is red just as it should be with no burned smell. If there is no TV cable is there some other adjustment for the 2-3 shift?
Thanks for listening
Transmission experts tell me what you think!
HotRodr56

[Fireplug]

4l80e e stands or electric controled.
Check your TBI unit how many cables on it??

[HotRodr56]

2 cables. One for the throttle ( gas pedal ) One for the cruise control. So no TV cable required? I see kits offered to correct shifting gremlins etc etc for the 4L80E, any experience with these? I plan to install a temp gauge to monitor the trans but the quirk of D not working all the time kinda bothers me. I put on slightly taller new tires when I got the truck, any way this factors in with the problem?

[Fireplug]

I would disconnect the neg battery cable for about 5 min and then take it for a hard ride (get into it) to let the ecm relearn the shift points. If that does not work post it here

[HotRodr56]

Thanks Fireplug, BTW thanks for the help on the TBI idle problem. I will give it a test ride and report back.

[HotRodr56]

Thanks,
All seems well after several days of driving and towing. the battery disconnect did the trick.

[Fireplug]

You are welcome