Stop killing your back! Lifting large dogs into a vehicle can be a pain. If your large dog needs a helping hand into your high-seated tow vehicle (and 51 inches is high), try this tip from Gregg at RVHaulers.
Dogs seem to get familiar with new steps and ramps fairly quickly, so not a lot of training is required.
Commenter Lou said,
I love this, I was wondering how to get my Great Dane up in the cab. I bought a ramp but none if my dogs liked it or would use it. This is a great solution.
Besides these steps, you might use a special dog harness to help ease your best friend into the vehicle. Pet Loader makes a variety of steps. The model Gregg referenced in the video can handle up to 250 pounds!