- First.. take a deep breath then...

Assuming it's a ZF 8HP auto gearbox

1. Try programming with one of these: https://uk.launchx431pro.com/products/launch-x431-immo-elite?spm=..order.order_detail_1.1 

2. If that doesn't work then you have one of the gearbox ecu's that needs its EEPROM memory cleared and before using the above tool will need to be cleared (to allowing reprogramming from another car to yours) with this separate tool - https://www.ebay.co.uk/itm/385601604267?hash=item59c7a58aab:g:CQMAAOSwWbNkWfUp&amdata=enc%3AAQAIAAAAwCWrKGBk2JQEKGWEXZYhJP6Jgbg2LjtJVQSjU0DtfRdoVRfDxm8lJncutKOw4yC9Ao2WvBbiay4FcHwBEikqXh6bT%2BqqZooC6uuTo2r02p6E8Go%2F1VhJQ7zOf41Lpnj3mRdQOlJUTyZ0fmlwnShc%2F1BRvdhLj6yJTCgwHGVCSCIpIuS1nZn6vCEdf55iFKJuCWCI4Ot6TTzWFqso0Os73dM5evMs9AbDSag1fqO294yU8EajBTFgr%2FQoiM%2Fj2s7OyA%3D%3D%7Ctkp%3ABk9SR-y3y4KJYg 

You may also need to purchase Module 19 option on this device depending on gearbox model no.

As part 2. above is a bespoke tool only for these gearboxes then its probably uneconomical to buy the tool for one use unless you do these all the time.. so if you carefully remove the gearbox ecu from inside the gearbox and send it off there are people via ebay that can clear the flash/eeprom memory and post the module back to you for a fraction of the price.