Hi all,

I have a 2017 ford edge, I had a gearbox service 3 weeks ago.

On my way to work last night, an amber transmission warning light came on followed instantly by red!

I stopped and went back to the car this morning, no coolant so put water in, found the thermostat housing had completely separated. Had it towed to my local garage. When they took the under tray off they found the gearbox filler plug and loads of oil on the tray. They won't touch it for obvious reasons and blame the other garage that did the gearbox service. Who are denying any responsibility.

Now stuck with a duff car.

Anyone any experience of the above?

Does loss of gearbox oil cause overheating etc?

With no reasons or evidence... to me, it looks like two separate faults, the thermostat housing has broken, causing loss of coolant leading to one warning.
If the transmission plug came out then that would cause loss of that fluid and transmission warnings.
We don't now which fault codes triggered the warnings and the sequence of faults.
Loss of gearbox oil would damage the transmission (hopefully it may have been protected by the warning light and stopping immediately - likewise the coolant loss)
If you have stopped in time then new housing, plug back in, refill both may fix it. If there has been damage then that will have to be assessed and fixed.
The issue of the plug falling out does appear to have been the responsibility of the garage doing the service (if it hadn't come loose until after they worked on it it is a serious co-incidence) but proving it is another matter?
https://www.citizensadvice.org.uk/consumer/buying-or-repairing-a-car/problems-with-a-car-repair/
If you can get some evidence or an engineer to attest that the garage were responsible then a Small Claim may be appropriate:
https://www.citizensadvice.org.uk/law-and-courts/legal-system/small-claims/deciding-whether-to-make-a-small-claim/

Cheers, no overheating issue came up and I stopped as soon as the red transmission warning came on, I have googled the gearbox problem and the answer is a yes to it possibly causing the thermostat housing to fail.

Gearbox garage now taking responsibility for gear problem, just have to get them to admit liability for thermostat issue.