Hilux Surf

G'day PG.
I'm not familiar with the oil you have in your vehicle, but it IS suppose to have Dextron II ATF in it.
I would completely flush the system and refill with the required fluid.
Incorrect fluid will have an effect on shifting, and life of the transmission.
As per my previous posts, I get around 480 - 500 kms per tank. I have a mandrel bent 2 1/4 inch exhaust and a Finer Filter element.
I will soon play with the injectors and boost to see what else I can squeeze out of it, as well as a snorkel for air ram effect and cooler air intake.
Re work shop manuals.
A friendly (if you can find one with your Surf) Toyota dealership can supply the following manuals which I have.
$ Runner Repair manual for Chassis and Body Aug 1989 (same as your vehicle)
@L - 3L Engine Repair Manual Aug 1988 and Repair manual Supplement 2L-T - 3L Jan 1990.
There is also available an EFI supplement, photocopied in Japanese which I found not much help!
All up around $160 Aust.
I also have the HaynesManual for 4 Runner 79 - 96 Diesel workshop manual.
Pretty much covers all bases.
it cost around $40 Aust, and you can get it at any Repco etc.
Anything that these can't help with, see a decent mechanic.
Hope this was of help mate.
Best wishes from Sunny North Queensland.

Ken
91 Surf SSR LTD