I just purchased a 2003 V8 4Runner sport 2WD and while reading through the owner's manual it states that the differential requires 80w90 gear oil. I noticed a lot of you are using 75w90, and although there isn't much of a difference, I wanted to find out if there was any particular reason? I don't think the 80 (cold) weight as opposed to 75 will matter for me, since I live in Texas; but just wanted to find out the reason why.
I'm enjoying the heck out of this thing so far. Tons of power, great handling, etc. As long as it stays as reliable as Toyota's reputation has built itself, I will be happy to drive this thing for a long time!
I ordered 3 bottles of the Amsoil 80w90 gear oil and plan to change it every 50-100k miles. Does this sound reasonable? I do drive pretty hard and will do some occasional towing (just pulling my stripped-down race car to local AutoCross events and other 'utility' stuff).