Gear selector not lit up

if you are stuck in gear it is not a basic rebuild but a bad rebuild
because of the design of the gear selection process , it is impossible to have 2 gears selected together as one selector shaft will not move unless another selector shaft is in the correct position ( neutral ) to allow the detente balls to move out of the way so the next selector shaft can move
it is possible that the gear stick is not in the correct position when it was installed back onto the top of the box and one gear was selected and the end of the lever came out of the selector slot or all the selectors were not in the neutral position and so the end of the lever went behind a selector rail
pull the gear lever turret of the top of the box, move the selector rails until they all line up as a slot across all of them , then put the gear lever end back in that neutral slot

You should go to www.reliable-store.com they have got books on every vehicle and also how to service/repair it, parts info, fuse box, gear box, torque specs,coiling, wiring diagrams, electrical diagrams, fuse diagrams, error codes, etc everything

The speedometer is operated by a cable to the transmission. The gear selector is also a manual linkage. Neither are electronic. There may be something stuck underneath inferring with them directly.

There is an electronic device that is attached to the transmission and tells you what gear that you are in. If that is faulty, then it will show the wrong gear, and may fluctuate, going from one gear selection to another without changing gears. This is simple to repair if you have some tools, the part money, and about 30 minutes.

i think so as well ,think you may have cooked the gearbox computer

Did you check the fuses?

Check for water in the transmission selector pack.

After rain or a good car wash,water can get into this transmission gear selector/sensor box.

attach to transmission, and move/select by the linkage RND21 movement.

I have to replace my selector box because the bad contact tell the trans computer it's on a different gear!

You need to give the car a scan, preferably with VCDS (or VAS at a dealer). If limp mode is activating (lit up gear selections), then it will be storing codes.
The fact that it works to a degree could be good news, the gear box has likely not failed. Could be the F125 selector switch, which is a common fail at this age.

Check your fuses,then replace the overdrive relay,if not this,they sale an bypass plate from IPB,for about 40 bucks,very easy to install.

Hi, chk ur rear transmission mount.