Clunk when downshifting pulling trailer

punomatic, you wont believe it, but I had taken it in 6 times, and each time they lubed the spline. each time I told them it was a clunk sound. this last time I went in and said same thing. They called me and said the test drive did not make a clunk sound. they shoed me a tech order that said if I complain of a clunk sound when shifting that is normal. I made them go for a test drive. when I stopped there is the clunk sound and a little bump. was told the tech order for a bump is to lube the spline, if this occurs again then need to replace spline and special grease. they did this. why did it take 7 times????
clunk and bump are 2 different issues according to dealer