had the tranny rebuilt after 190000km (120000mi) now it's 240,000 and it seems to have a high sounding pitch in idle when it's cold. Changed the fluid 6 months ago, doesn't smell burnt. Any suggestions?

 

I suspect you have a bit of excessive clearance that is closing up after the transmission warms a bit. These transmissions seem to be right on the edge when they are new and can experience all sorts of leakage as they get a bit worn.

Take a look at the forum on DTT's site and you may find your issue discussed. http://www.dieseltrans.com