Car has low and reverse, but wont shift out of low, this is a 1994 Audi 100cs

YOU NEED TO SEE A TRANSMISSION MAN, THIS DOES NOT SEEM TO BE A JOB AN END USER CAN TACKLE. aLMOST CERTAINLY GEARBOX TROUBLE I am afraid
Good Luck with it

Check your E-break first, secondly check to make sure you have no errors kicking from the control unit (engine computer module) which may or may not trigger a check engine light. Moreover it could be several things. Since it's an automatic the drive train maybe damaged, controller unite could be damaged, the transmission could (and probably) is dying. I'd have a professional mechanic check it out.

either you have lost the reversing gear or the gear shifting solenoid will not work.

Maybe a fuel pump on its way out

5w30 is recommended up to 100 degrees. over that and it is recommending a 20w50. I would use a good synthetic 5w30 which is good for much higher temperatures and will easily perform well in the +100 degree range as well as the -0 temp range. Mobil 1 or Amsoil fit the bill nicely.

it is safty in the tranny have it scan

On the low side charge outlet, right on the compressor itself

If you have acess to a mutimeter check the batery voltage. Should be around 12.5 volts. also check batery voltage when trying to crank engine. Should drop to 9volts while cranking. If it dose but engine dose not turn over you know power is still going to the starter motor but its just not turning. This could be a bad conection in the starter some where.if voltage dose not drop you know power is not reaching the starter motor. this could be a bad earth to the starter from the baterty somewhere. But also listen for clunking or clicking noices while cranking which would surgest the starter is trying to turn. try this before doing any other diagnostics.hope this helps

The seals in the transmission In the clutch apply are hardened or have flipped over and cracked. A rebuild wil fix this.

check the switch to turn on the air. it might be loose.