Can I have my truck towed to the dump whether, or not my mom approves?

No you can't, Unless you bought it and the title is in your name

How old are you and is the truck in your name? Do you provide anything of value to your living arrangement?

Do you have another form of transport or are you going to expect your mother to sacrifice all of her time to haul you around as your private chauffer? or do you simply expect her to hand you the keys to her car when you need transport?  Oil is a natural mineral naturally found in and on earth. Unless it is leaking oil by the quart fulls every 50 miles, it is not going to hurt anything. in fact the energy and raw materials required to make another vehicle to replace your truck that still runs will create thousands of times more pollution than an operational oil leak.

Listen to your mom.

fast repair- gaskets around the il pan or in the valve covers. You can get a mechanically incline friend repair it for your mom's sake. Don't let a small thing create animosity between you both. Find the gaskets online and for around $75 you'll make your mom happy and save the environment. or tell your mom to buy it off from you after having the truck repaired. 

That all depends on who's name is on the title!  If it is yours, yes; if it is her's your stealing her vehicle!  Now think on that!

Whose name is on the title? If it's her name the junk yard can not take the vehicle. They need a clear, signed title.

Whatever you do, get your name off of it.  Put it in her name and walk away from it.

.

Drive your truck to the junk yard. Give them your pink slip. Walk home. The issue sounds mostly emotional, but if it's your truck, do what you want. If you get into it with your mother in the aftermath don't come here crying about it. If they give you any money for the truck, use that for your counseling sessions......sessionS. If the truck is hers, then hands off and mouth shut- the end.

yes she can if she owns it then your stealing her property , if it yours you can do what you like . Whose name is on the registration or title, or did she lend you money to buy it and you havent paid her back !!!

If you own the truck you can junk it.

It is your truck, you get to decide.  But if you are living with your mom, it might be in your best interests to let her have the truck.