Yes unfortuanately, the TCM on the 6HP26, is built into the gearbox
so swapping the gearbox, will cause loads of problems and the car will not even start
the gearbox tcm is networked and talks to most of the modules on the car
it would need programing to the car with something like Jaguar IDS/SDD
lots of jaguar indy's have it and should be able to program it, problem is once you swap the box your stuck, wont drive or start
Serviced my gearbox a few years ago and only used genuines part and oil, ZF lieguard 6, lots of people use cheaper oil and end up with a host of problems after
usually the main problem is the mechatronics, which is the valve body in the bottom of the gearbox, this has the tcm built in, you can get service kit which will cure most faults, like a sonnax kit, which replaces all the little pistons and valves in the body , also a set of solenoids whichs controls all the gear selections and clutches, is usually replaced which comes seperate.
also if the software is the original build that can cause problems, updates can cure a few issues like banging gears and surging when cold, a adaptation reset will also be required, this clears all the learnt data the gearbox learns and helps the gearbox to drive smooth again