hey everyone...

new to the forum and just bought my first truck and first toyota last week!
It's a 1991 Hilux Surf 3.0L V6 auto, 96000km's (stock). If you've never heard of it, it's basically a right-hand drive 4Runner. So far I love it (except for the fact that my radiator fan exploded... )
So... it has the same V6 that's in the 2nd gen 4Runners, and I've searched for everything I can think of to get my answer but I'm coming up short.

I live in the Vancouver area of British Columbia Canada and I need to know what oil i should be using? It's been known to get down a little below -10 C (10-15 F) in the winter and up to about 35-40 C (100 F) in the summer.

I bought a Haynes manual, and the viscosity chart in it isn't engine or model specific. It says that 20w40 would cover me best (-20 C & up), but I've never used 20w40 in any engine ever... and I used to work an a oil change shop.
After some digging online, I found a PDF file for the 2nd gen surf owners manual. It says that 10w30 would work best (-18 C & up).

I've personally leaning toward the 10w30, but figured you all probably know which will work better than me, so I have come to seek your collective wisdom...

Also, Please correct me if any of these are wrong (I tend not to trust Haynes manuals too much these days):
Transfer Case - ATF
Differentials - 80w90
Power Steering - ATF

 

I think 5w oil is generally recommended for overhead cam engines, though I've heard it's best to switch to 10w in high mileage engines. I personally have always owned high-mileage vehicles, always lived in cold climates, and always run 10w-30 with no problems.

 

5W-30 synthetic would help to lubricate just that little bit more on those coldest of days. Then go to 10W-30 for summers.

Just my .02.

Keep it changed often and which one you run is not as critical.