I'd seriously be considering an extra transmission cooler.
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I'd seriously be considering an extra transmission cooler.
You may find it less stress if you invest in one of these gauges.
ENGINE WATCHDOG TM4, Engine Temperature Sensor and Low Coolant Alarm
Engine & Transmission temperature 52mm gauge - visual/audible overheating alarm | eBay
Both can be 'plug and play' and only take about 2 beers to fit. (2 beers=30C day= 1/2 hr). And could be sold after the trip if desired. (NB; they are addictive tho'!)
I have used both and can recommend. Engine temps read 2-3C lower than Nanocom but will equalize after about an hour doing longhaul.
You can set alarms on both so you will not have constantly monitor them.
If you want then you can drive to your engine and trans temps to find your happy place between 3rd and 4th.
If you are leaving soon then you have picked the best time of the year for this trip.
Safe travelling...
IMHO the two most important gauges are EGT and boost.
Keep the EGTs under 700c at all times, and this may necessitate changing down to 3 on hills.
I recently returned from Yarrawonga with my new old van which weighs about 1550-1600Kg.
I suddenly noticed high EGT and low boost. After investigation it turned out to be that the blow off valve shaft had unscrewed itself.
I hate to think what would have been the result if I had kept driving.
You will tend to change gears manually after awhile with a load, and feel for lockup of the transmission, I found best to change down early on hills at say 80Kmh then ease off to enable 3 to lock.
Lock will be slower if you have heavy acceleration so maybe that is why you are finding that as the ECU is programmed to lock at 80KMh in 4.
Anyway there are hardly any hills from Perth to the Kimberley anyway!
Regards PhilipA