Toploader fluid?

[Timbo]

I have a toploader and want to change the fluid and bought some Pennzoil SAE 80w-90 GL-5 multi-purpose gear lube.But before I put it in, I am wondering if anyone else has used it and liked it or if I should use it? I wont use a synthetic oil in a toploader that was built in 71 back when synthetic oils were just a wet dream. Any thoughts would be great before I change my fluid

[REDSC400]

Hi Tim:
I had a similar discussion with David Kee and the guys at ERA over the last year or so. Both sources reccomended that a Non-Synthetic oil is best and both suggested 75W-90 so that is what I have used. I used the Castrol brand. About two quarts fills up the box to the filler hole.