Yes, it is really not a good idea.
drain oil from oil pan. theh add oil
There could be a few possible reasons for hydraulic oil spilling from the fill cap when dumping a dump truck. One reason could be that the hydraulic system is overfilled, causing excess pressure and resulting in oil leakage. Another possibility could be a faulty or damaged fill cap, causing inadequate sealing. It is also important to check if the dump truck is tilted or positioned unevenly during dumping, which could lead to oil spillage from the fill cap.
overfilled engine oil
If you overfilled the oil then you can drain some out. There are small hand held pumps that would work fine for the purpose. The exact process would depend on what you overfilled and how much. If the overfill is slight it might not matter on some things and be a big problem in some other. You did not say what you overfilled to give a real exact answer.
The engine oil is overfilled.
Because it's been overfilled, or you're using the improper weight motor oil
Your engine is most likely overfilled with oil. Check your oil and make sure it isn't overfilled. However a little oil coming out the exhaust isn't gonna hurt anything, your just gonna waste a heak of a lot of oil
oil will pour out. that's what the dipstick is for. Check it and if needed, drain some out.
You overfilled the crankcase!
You have overfilled the engine. Drain the oil to the appropriated level.
You have overfilled itOr you have a leaking sealOr a crack in the housing.
IT may have just been a seal, but still that's not good. Check aroud the rear main seal. Or just take it to a shop.