It's interesting you say that Trevor, that they took the OEM cooler out of the equation.
Many years ago there were regular discussions about this. The early OEM oil coolers in the corner of the rad had metal "fingers" installed in the intake. Their purpose was to act as a flow disrupter, a turbulator. The idea, a sound idea in fluid dynamics terms, was to create turbulence in the flow of hot oil into the cooler. This was intended to negate the surface drag effect, which left cooler oil clinging to the metal surfaces with the hotter oil flow passing quickly through the centre, and not cooling as it should, thus decreasing cooling efficiency.
What happened was the clutch material fibres tended to cling and build up on these "fingers" over time. With enough gunge sticking there, and no additional filter taking the gunge away, flow was seriously restricted to the cooler, allowing the gearbox to overheat and eventually burn out.
Later radiators did not have the turbulator fingers after the problem was understood.
By giving you a new cooler, and cutting out the OEM one in the rad, your transmission guys ensured that any material clinging in the original cooler could not be dislodged at an oil change and make it's way to block passages in the transmission.
A good solution, once your new slimline cooler is up to the job of keeping things cool.
Joe
