Case 721c shifting and brake issues

Purchased 2000 case 721c 3500 hours at auction
original issue of only first gear working and going into protection mode “neutral”. Machine would move again if restarted. noticed it wasn’t reading speed on the dash so replaced speed sensor. Now it will run and drive all day but only in 1st gear. 2nd 3rd 4th never work.
Beginning to believe this has something to do with the low brake pressure on the pedal keeping it in downshift mode or something. The brakes work but upon starting the machine you have to pump them up to get the low pressure warning off and to get it to engage into gear. Also the pedal never returns all the way up right by itself, you have to pull it back up with your foot or the brake lights stay on. Anyone familiar with this issue of brake pedal not returning up on its own and 2nd 3rd 4th not working ? Could they be related ?

Hi D ERC,
the 721c got a ZF 4WG180? With EST 17 or 25 electronic box for transmission? Gear selector a DW2 or DW 3?
I doubt the issue with only 1st gear working has something to do with brake pressure or pedal. This is another issue.
1st gear: Please check signals from gear selector. These must change with moving selector. Switch to neutral (protection mode) I'd assume lack of F, N or R signal. One of these signals must permanently be active, but only one of these.
Please confirm, correct or negate above questions for deeper assistance.

I checked the requested gear selection check signals in the dash and all read good
But when I do the actual gear check it displays limp home mode 115 in forward,
200 in neutral, and 315 in reverse

my codes are 46242 current I’d not set or corrupt
And 46018 popped up but doesn’t make sense due to the requested gear selection test checking out

So I'd guess the Case 721c got a modern ZF 4WG190 or so with EST37 TCU.
The system more or less immediately jumps into limp home mode with only 1st available.
Most likely an electrical issue with broken wire or short in wires or connectors from TCU to control valve.
TCU is possibly located underneath/behind seat, control valve on back of tranny.

I had traced a harness headed towards the front of the machine that hooked into the brake sensors a couple hours ago and found 5 pinched wires shorted to the frame. Insulated them and correctly re routed them. Only thing it fixed was brake warning alarm still stuck in 1st gear. I will try to trace the harness to the tcu . This is my first wheel loader and know nothing about the model of the trans or control

How do I configure the dash on the c series to fix the current I’d corrupt code , service manual doesn’t say

Thanks for the help but got it figured out, went through programming and someone had the transmission control set to a 621 series not 721. Called case for the trans programming code and set it all correctly and now the transmission shifts through all gears as it should.