What is the Life Span?/how long do they last?

Dodge vehicles in my area are notorious for having tranmission trouble after 100k miles. Rust will be your biggest problem. I would recommend only keeping it for around 5 years.

Have seen these used daily by a funeral home as transfer vans with 300k miles on them.  I would not worry.  I was a Dodge service advisor, transmission problems are less likely on the 2000+ models than on the late 1980s-mid 1990s models.