Rebuilt 8.75 Sure-Grip - resistance and clunk

The problem is your shop. Anything I can't or don't want to do myself is done by my old school mechanic who has nothing but old school mechanics (all over 50) who work for him. He then personally drives and tests every vehicle that leaves his shop. If it's not to his satisfaction, he doesn't call to say it's done. He might call and say I need more time and I say fine by me as long as it's right. Take it back and tell them to get it right. Worst case, they say some parts are bad and still need replaced.