2015 Prostar wont go past 5th gear fault code 71

Truck has run fine until it wouldn't go into reverse. My alternator voltage was down. I replaced batteries. Not sure if I connected batteries correctly. Not negative to positive. I've heard before that the first battery should some how be connected by itself or some along those lines. I've read through the other threads regarding this issue. I paid a service truck to come out yesterday but I know more about this truck than he does. So I'm still broke down at the truck stop diagnosing the problem myself. Could it be low on fluid or need clutch adjustment. Some please help.
@Heavyd, can you help?

 

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If it's running 1-5 fine (low range) but won't go to 6-10 (high range) most likely it's the range solonoid.. ...

On most trucks it takes about 1 hr to change it...

What's the full code.....?
Spn #
Fni #
Sa #

 

It only shows code 71 and 27. No more codes. Thanks for reply

 

are you using the self diagnostic thru the dash...
With the key on (not started) press the cruise control "on" and "accelerate" at the same time. Guages well swipe and the display will show all active and inactive full codes...

 

I changed range sensor. Still only goes to 5th gear. Codes are below. Thanks.

 

I changed range solenoid and still 5th gear only.

 

the #2653 is the low beam driver side.
The #560 is your problum "transmission driveline engaged"... not a clue what that means