I'm trying to locate the Transmission Control Module. Can someone point me in the right direction? 2004 XJ8 Thanks

The TCM is within the transmission, that's why you can't find it. There is a connection to it via a multi-wire socket at the rear of the gearbox. This allows information to be exchanged between the TCM, the ECM, and other modules in the car.

Why do you want to get at it ?

I have a 2004 xj8 with about 100000 miles. Occasionally at highway speeds it will downshift and set a transmission fail code. Pull over turn off car and restart the code is gone and car functions normally. It had never set the check engine light until yesterday. Code PO735. I have a parts car and was going to swap the TCM to see if that would fix it

It probably won't fix it. Also you need Jaguar diagnostic software to flash the TCM to your vehicle. Try a fluid/filter change. There are also seals from the TCM to trans unit that can be changed but I wouldn't be hopeful.

I would consider swapping the entire trans from the parts car and take your TCM out of your car, swap it and change the seals.

it says in JTIS p0735 is a 5th gear ratio fault .
ECM torque signal fault , transmission mechanical fault .
most likely a solenoid or clutch pack issue .
id check to see if there is any oil within the mechatronic plug first at the rear of the trans. then dig deeper .
but i doubt its the TCM.

The mechatronic plug is dry and I changed the fluid and filter. I would not consider using the parts car transmission it has 150000 miles on it. Not looking good.

More than likely your E clutch is toast.

That would not be the best outcome

Agreed, unfortunately. Take it from experience. I had a 3/4 gear load code. I swapped a TCM from A low mile vehicle and seals, genuine ZF fluid & filter, tcm harness seal & reflash of TCM and no go...

Well thanks for the input. There is no point in following a traveled road when you know it ends in a dead end. The car is quite drivable now. That will give me time to source a good used transmission.