All aus delivered xj's had a trans cooler I believe. I bypassed it and the rad heat exchanger and went a standalone to keep temps down. Towed over 2T with ease ;)

i by passed both of mine as well. and went with a big after market cooler. then I plumbed the power sterring into the OEM tranny cooler.

I towed a 1t camper trailer from Bamaga back to Hervey Bay with a completely squashed trans cooler line, the transmission screamed on any sort of incline, after rectifying the trans line it was all good.
The gearbox is fine in the Xj as long as keep things within reason, I always towed in the same gear that I would normally drive in so on the highway it was in O/D and never an issue.
For regular towing a transcoder upgrade and/or radiator bypass are well worth looking into.....

The oil has come up good and my filter arrived today. Just in time to go on holiday to the mechanics because of noises when driving 40 k or more.

Seems the front diff has issues, hopefully just a bearing....
also the u joints are giving out too. I'll find out Monday.

Well.well.