Hi RRPhil, so if I understand what your saying is locking up the TCC earlier is not a good thing when towing, because the car will shake it's self to pieces. OK, I'll except that L/R have screwed me over there, and theres nothing I can do about that.
But will the addition of an extra oil cooler and filter be a worth while addition or a waist of money?

It’s widely reported that, when it was launched back in 2002, the L322 had had the most expensive development programme of any car in history. It’s unlikely that a major flaw like inadequate cooling capacity for the transmission made it through into production.

Oil-to-water coolers, as fitted to the L322, are superior to oil-to-air coolers for the following reasons :

1) Automatic transmissions with torque converters fitted with lock-up clutches produce the majority of their heat load at low vehicle speeds, where air flow is at its minimum.
2) Water has both a higher thermal conductivity and a higher specific heat capacity than air and therefore requires a lower volumetric flow to shift a given heat load.
3) An oil-to-water cooler also acts as a transmission fluid heater at low ambient temperatures as the engine coolant gets up to temperature much more quickly.

In my opinion you’d be better off spending money on ensuring that your existing cooling system was operating at full efficiency and therefore doing what it was designed to do. Issues with both the main radiator and the oil cooler becoming blocked with age are very well documented on here.

Like I say, just my opinion…..

Phil