None of my light was on. Everything was working fine. They had the vehicle disconnected for a while. Connected back up and all the lights was on. It took the vehicle home, disconnected it for about 20mins and connected and drove a mile but lights still on
ABS lights, like check engine lights are just fault indicators. You need a scan tool to read the ABS code, and that will actually tell you what the fault is so you can start trouble shooting. Note, not all scan tools (like the free to borrow ones at auto parts stores) will read ABS codes. Any actual mechanic will have a scan tool which will read them. It could be something like my story below…. If they replaced the transmission they may have removed the axles from the knuckles… there generally isn’t enough play to pull the axle out of the transmission without getting it loose from the knuckle first.
Story time. I’ve had an ABS code come up one time on my Mazda 5 after replacing the front struts. To facilitate getting the strut into the knuckle I loosened the axle nut so the spindle could slide out a little bit and give me some play. When I reconnected everything I apparently didn’t get the knuckle seated all the way back onto the spindle…… still had the axle nut with locking pin on, so it’s not like the axle came loose. It was just a couple of mm out of position. But that made the speed sensor on the knuckle not be able to line up with the notches on the axle so it can measure the speed of the axle. The speed sensor is an integral part of the ABS, and how it decides what speed each of the wheels is spinning and when to engage the ABS. Since it couldn’t read one of the wheels it threw that fault code. The code being active made the ABS be disabled since it doesn’t want to engage a system it can’t trust the data on.