I am trying to get a job in transportation. I retired from the construction industry due to back surgery.
The company is stalling on hiring me because of my surgery. I had the surgeon send them a release but they are still stalling. I was wondering is there any kind of legal form I could sign releasing them from any liability if I was to be injured from this pre exsisting condition. I really need this job and I want to do whatever I can to get it.

Each trucking company has a different insurance carrier. It's whatever the insurance carrier dictates to the company that matters. You might ask their recruiter what for documentation you require from your doctor before they would even consider hiring you. Truck driving is very hard on the lower back and kidneys and is not for everyone. Having had back surgery they probably don't feel you are a good candidate to drive a truck. It's not the trucking company, it's their insurance carrier they must appease.