yep, although i'd imagine it's much much easier to clean most parts (block, camsas opposed to an oil cooler, simply because of the design.
the context it was mentioned to me was if someone had blown their engine, and all kinds of shit/metal etc had got pumped into the oil cooler where it will then sit until the cooler finds its way onto another engine and all the crap is pumped back out again round the engine with nasty results.

as mentioned earlier though, may well be not so critical when it comes to transmission components as i guess the tolerances are a bit bigger than you'd find in big ends etc (?)