G'day Simon,

I reckon the tranny upgrades are one of the essentials especially if your goin' to tow heavy and a lot. Those upgrades will IMHO get the best out of the OEM tranny.
Only about 3K km after I bought this truck in 2006 the Tranny **** itself big time later that year. Got a rare crack in the fluid line going through the radiator bottom and contaminated the tranny and it threw a hissy fit on me .
Anyway because it was only registered in Feb 2006 it was still under warranty and Ford got it fully re-built including TC and fitted a new Radiator all under warranty.
Anyway I straight away ordered my JW VB & Filter off Clay and figured a 5K km run was a good flush/run in. So I dumped the Dino Fluid, changed the Filter and fitted the new filter and JW VB. I already had a BD Deep pan and filled her up with Castrol Transmax 'Z'. Ran it for another 2K km and changed the fluid again (with Castrol Transmax 'Z') and figured that should see it right for a bloody long time.
I've researched Auto longetivity and the boffins reckon that 99% of contaminants and residues found in Auto boxes are caused in the initial 10K km of use in a new or reman box. They say that a change of oil twice and a filter change within that first 10k km increases an auto boxes life substantially and is relatively good insurance practice.
I've been pullin' heavy, mountin climbing and bush driving without any signs of dramas. So fingers crossed it will stay that way.

Cheers,
Reg