We tow a 2.5T caravan a fair bit (2009 D40 auto) and have replaced the auto box at 320,000km but that was because we took it to Bob Hunt Automatics in Maitland and that's just the LAST thing anyone ought to do. The guy butchered the gearbox. We had a little vibration as the TCC was engaging and when measured, the TC was slipping a little more than it should. We were told a rebuild of the TC would fix it.
So, hand over the car with a "yeah just $500 to reco the TC plus fitting costs" and $3800 later I've got a gearbox that not only still has the same TC problem, but now it slams into second and third gear and feels like it's only a matter of time before it undergoes a rapid unscheduled disassembly. They also connected the transmission to the radiator - bad move, since we had (and they knew) external coolers and the radiator had been blocked off for a reason. Now, there's coolant in my transmission and my radiator is full of transmission oil.
If you are anywhere near Maitland, do NOT see them for your car.
Maitland Automatic Transmission Services (ATS) in Melbourne St said that a new valve body MIGHT fix the issue, but didn't promise that it would. They removed the old one, put in a new one, flushed the unit a couple of times to get the coolant out and had it reprogrammed by Maitland Nissan (ATS are not allowed to have the stuff to reprogram it, apparently). Maitland Nissan botched the reprogram and the TC was NOT fixed, but at least it went into and through the gears fairly smoothly.
So, stuff it, we put a second hand box in. That's what we should have done in the first place. Lesson learned.
Would I get a manual? No. With an external tranny cooler fitted (our Nav now has two in series), the gearbox does rather well, never giving us grief climbing hills like Thunderbolts Way or Kurrajong (Bells Line Of Road) although I do take extra care to slow down so that I don't overheat the motor.