I hate to be pessimistic, but I tried without satisfaction to add a transducer to my bow-mount TM. The goal was to use my old Lowrance Elite 4 DSI at the front of the boat. There's a new H-Bird Helix 7 in the back of the boat.
My first try was to use the integral US2 sonar built into my Powerdrive TM. However, it's not compatible with my Lowrance unit which needed a downscan capable transducer. The US2 is 2D sonar only. So, I decided to mount the Lowrance's transducer to the TM motor housing
I watched countless YouTube vids.
I bought a mounting bracket and clamped it into place up front.
I tried to put the cable into a pre-coiled plastic hose to reduce risk of damage to the Lowrance cable. I tried multiple ways of routing that cable.
There simply was no reliable way to keep that external cable from fouling on something the way my boat is set up. It was made all the more difficult because of the spot lock capability and the tendency in certain conditions to for spot-lock to wrap external cables around the shaft.
I gave up and converted my excess Lowrance fish finder to a portable unit that is easily moved from boat to boat. If I want it up front in my boat, I have a mounting bracket that will clamp onto the boat. If I want to haul that portable unit to Canada where we rent boats at the lodge, then I can use it there, too.