My Buick, which never had any serious issues , now has one. I started the auto .

I had this problem with a Dodge 300 my ex owned... She added power steering fluid into the brake reservoir and once she drove it a mile or two the calipers would lock the wheels in place.. She thought that because some people will add transmission fluid into the power steering units it would work in the brake system. What it does is once it heats up it expands and acts as it had the brakes on.. We had to replace the calipers wheel cylinders and master cylinders and flush the entire system thoroughly.. Expensive lesson learned. I hope that helps. If not I would think the transmission would be jammed or a bearing overheated.