Gas and greasy/rubber smells outside truck

It's out of sight so very easy to miss but you will smell burnt oil once the engine comes up to temp. That is because it drips directly onto the exhaust manifold right under it.

 

The smelliest fluid bar none is the gear oil in the tranny....

As it heats and ages it can stink to high hell.

We use to use an old van to move engines and trannys around.
Those old standards would spill....and that smell would be just as strong a decade later.
Worst automotive smell I've ever consumed.....

Synthetics wouldn't do that....but if that is the original......