Will not go into reverse ever other gear works

possible problem with gearbox

It may just need servicing/adjusting.

Your reverse gear is actually first gear ... when you select reverse another 'cog' fits into the toothed wheels to change the direction of first gear ... to give you reverse...

It may be a sticky valve or just a bit of adjustment (workshop job..) that is required.

What you can try ..

Start the car ... move the lever through all the positions several times (foot on brake..). Keep your foot on the brake and then put it in reverse and rev the car. Hard!

Try doing it several times.

An auto transmission works on valves opening and closing. Reverse gear - in comparison with the forward gears - is seldom used. The reverse valve can 'stick'. Try forcing it to open ... frighten it ... but keep your foot on the brake...

run fault codes and look for a reverse solenoid/ servo or TCM fault.

Try shifting to 2nd gear and then into reverse to stop gear roll over.

be careful when changing gears into reverse and be careful while in reverse and your transmission should last but if you ride on that gear to much your transmission will fail and you will no longer have reverse in your vehicle even if you have all other gears working

first thing to check is if the break lights are working. if not reolace the stop lamp switch under the car.

sounds like it's time for AAMco for a free estament

If I understand you correctly, you have ALL forward gears working, but reverse doesn't?... then the problem is in the transmission itself or the linkage on the trans linkage into reverse.

My VW is not shifting into reverse at all; I think a certain person was driving and mistakenly pressed the gear shifter down for all gears--reverse is the only gear you press the shifter down first in. Doesn't grind, 1 2 3 and 4 work but no reverse no reverse lights.
I've read several complicated (can't see scenario's) posts on screens and linkage and a cable fixed one guys problem but still no solutions.

look at reverse servo piston. it affects the reverse band.