E34 535i Auto

Hey, recently Bought an E34 530 Manual and a 535 Auto. The Auto box gave up, as they do, and was replaced with a 735i Item. The car starts and Drives but only in 3rd Gear, so as i'm sure you can imagine, its a torture.
Has anyone any ideas as to the cause of the Problem or how to sure it. Failing that, what about converting it to Manual? Which gearbox will fit (89 Model Car)?

Do you have the automatic/manual slider switch to the left side of the gear selector?

If you do then you might be in the manual shifting mode.

(You can tell if it says M D, or M3, M2 depending on what gear you're in, on your HUD.)

If it says this on the HUD then push the automatic/manual switch up to the "A".

The "M" should switch to an "E". Unless you're in 3rd or 2nd or 1st then it'll show an "S" with the gear.

If it doesn't...I can't help.

Sorted, ish! Turns out that the car went into Limp Home Mode when the origional Gear Box gave up and the computer hasnt been reset whn the origional was rplaced, so a trip to the BMW Garage should sort that, fingers crossed!

Here's hoping!