4L80E Hard 1-2 Shift, 91 R2500 6.2

Greetings,
I've got a 91 R2500 Suburban, 6.2 diesel with a 4L80E and 116k on the clock.
The truck has not been driven since October on a 70F degree day
at which time it shifted normally from 1 - 4 (OD). It's been sitting since then until today when I finally got tags for it.
Now, on a 45F degree day, I'm getting a hard 1-2 shift no matter how hard or lightly I'm into the accelerator pedal.
The ATF looks and smells normal, and the other shifts, 2-3, 3-OD are fine. Don't know if the trans is showing any codes as I can't find my GM code reader at the moment.
Is this likely to be:
1) A bad/stuck/disintegrated TCC valve in the valve body?
2) A bad 1-2 shift solenoid?
3) Loose wires/connections (the trans was disconnected though not removed from the truck) for a while)?
4) Bad valve body?
5) Getting ready to need a rebuild?
TIA for any and all responses/suggestions/pointers, etc..
--Duncan
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. . ===== ===== snipped-for-privacy@radix.net (Duncan D. Sterling) writes us:
Greetings, I've got a 91 R2500 Suburban, 6.2 diesel with a 4L80E and 116k on the clock.
The truck has not been driven since October on a 70F degree day at which time it shifted normally from 1 - 4 (OD).
It's been sitting since then until today when I finally got tags for it.
Now, on a 45F degree day, I'm getting a hard 1-2 shift no matter how hard or lightly I'm into the accelerator pedal.
The ATF looks and smells normal, and the other shifts, 2-3, 3-OD are fine.
Don't know if the trans is showing any codes as I can't find my GM code reader at the moment.
===QUESTIONS===
Is this likely to be: 1) A bad/stuck/disintegrated TCC valve in the valve body?
2) A bad 1-2 shift solenoid?
3) Loose wires/connections (the trans was disconnected though   not removed from the truck) for a while)?
4) Bad valve body?
5) Getting ready to need a rebuild?
TIA for any and all responses/suggestions/pointers, etc.. --Duncan ////////////////////////////////////////
Duncan, any?? all??? okeee dokeeee, here we go.
Answers to yer questions 1) No, not likely
2) No, not likely
3) No, not likely
4) No, not likely
5) Yes, likely
Responses:
my first response was....... laughter.
my second response was...... some of the above answers could be changed if your question had entailed the word "possible"....... instead of the word likely.
my third response was....... wondering if i ought to help you find yer code reader......or......jest mail you another paper clip
my forth response was..... more a thought ..... someone has worked on yer tranny and you left out that little tid-bit of info.
Suggestions:
ask around and get the name of an honest tranny shop, call the local BBB and see jest how honest they are, then get the thing fixed. You're not a transmission technician, and you need one.
Pointers:
Double check that tranny and verify the model before attempting any further diagnosis.
Never leave out any previous work history that may help with the diagnosis. It tends to be a pricey way to fix things in the long run.
When you get to the tranny shop, explain to them why you disconnected the tranny....... but didn't take it out, i'm curious as to if they're gonna be as baffled by the logic of that one as I am..........or if'n they gonna be do'n what i'm do'n......thunk'n maybe you leave'n out a thing or two about the situation.
yw, postscript
~:~ MarshMonster ~:~
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: ====: ====: snipped-for-privacy@radix.net (Duncan?D.?Sterling) : writes us:
: When you get to the tranny shop, explain to : them why you disconnected the tranny....... : but didn't take it out, i'm curious as to if they're : gonna be as baffled by the logic of that one as : I am..........or if'n they gonna be do'n what i'm : do'n......thunk'n maybe you leave'n out a thing : or two about the situation.
Actually, to clarify, this was done by the previous owner. Lucky for me, it turned out to be a simple fix:
Adjusting the TPS.
When I checked codes a code 22 (high TPS voltage) came up. Using a voltmeter, I was able to adjust the TPS from over 5 volts at idle down to just over 3 (courtesy of the Turbo Regal site's suggested adjustment procedure).
Since doing that, the tranny no longer bang shifts and all is well...
--Duncan
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