99 Ram 1500 5.9 4X4 unable to shift into 4 wheel drive

I have a 1999 Dodge Ram Extended Cab 5.9L 4x4 with 66,000 miles and im having an issue with the 4 wheel drive transfer case. the Shifter linkage broke recently and had a shop put a new one in but now you literally have to use either a pry bar or punch and hammer to get the truck out of 4 wheel drive and back into 2 wheel drive. Fluid has been changed and no abnormal sounds coming from the transfer case. With the low miles and being 11 years old im believing that the 4x4 wasn't used too often and the internal shaft that does the selecting is seized or corroded . Is there a way without pulling the transfer case to free this up. Any information would be greatly appreciated. Thanks everyone.

I've had to back up a coupla car lengths to get mine to loosen up before.

Thanks Chris for the reply, lucky for me the dealer i bought the truck from is paying to have the transfer case pulled to have it repaired at no cost to me. I appreciate your info. and will most likely have many more questions later on.