Not sure if you could do the same with your dog as with ours...
Are cindy as you mite know is a golden retriver and has H/D in her back right hip...
What i do do as cindy will put her front paws on the back lip of the car estate end.... and i have a sling that i put around her back end to lift her up..If its dry i just lift the back end of her...
Or...If you have a handy husband that can do D.I.Y
A lenth of some tweny gage marine ply wood about a foot wide by some five foot long with treds across.... paint the ply wood put add sand in it to stop your dog from slipping on the main tred going up...Chris