I promised myself I wouldn't wade into these oil debates but here I am.
The spec for a 1hdt/FT is JASO-DH1 - this is an ancient spec from 30 years ago. Pretty much any oil will be fine. I use whatever diesel mineral oil is on special at the FLAPS near oil change time. I've run Penrite, Gulf...
These are considered the "standard" here in NZ. Dunno if he ships but he's easy to get hold of and ask.
https://acfab.co.nz/products/toyota-landcruiser-80-series
There was a factory one, 64901-60040-03. My HDJ81 has the brackets for it, not sure if it works with a third row, though i guess it could be trimmed to fit around the folded up seats?
ARB versus Corolla. Corolla hit us (we were going about 10km/hr, corolla about 60) as we were going around the bend behind us. The bar was a write off and the 80 needed a guard, valence and some minor panel work. Corolla buggered - you can see where the guy's head hit the windscreen if you look...
Tried the Nulon Slick shift additive? My Corolla has a dodgy 2-3 syncro and it really helps it.
(i know the VMX-M is the prefered option but this could help)
The KZ is a solid powerplant for lighter trucks - they suit Hiluxes, 70 and 90 series Prados and Surfs (see note below). The 1KD which is in newer Hiluxes is heavily based off the 1KZ.
I had a KZJ78 with a 1KZ in it and it was great, but the 80 or even the HD 70's are too heavy for them, they...