Title about sums it up. I've tried multiple different methods of extracting and inserting the fluid from a tank and into the dynamo but it doesn't work. I mean the fluid will not even go into the dynamo let alone actually use it as fuel.

Make sure the gasoline accepted by the dynamo is actually the one from pneumaticcraft because there's a few overlapping oil/gasoline fluids from different mods if I remember correctly.

If that's not an issue, see if you can get any other fluid into it which should work according to docs/JEI, if not, there may be some other underlying issue at hand.

From what I can see the pneumaticcraft gasoline is the only fluid named gasoline in atm8 at the moment. I did some testing and the dynamos except fluids from other mods fine, but it appears that no pneumaticcraft fluids/fuels work for thermal's dynamos. The tool tip on the bucket of gasoline directly compares it to thermal's refined fuel but jei doesn't show a use for it as such.

It looks as though pneumaticcraft fluids are not usable in advanced generators or by thermal expantion at all. Although the fluids do work for create's fluid blaze burner and a couple of them for ad astra, which I would guess is intended. I'm not sure what to make of it really.