Buyer beware: Do not return your core transmission...

Buyer beware: Do not return your core transmission until you install the new one and make sure it works well. On transmission number 4 for the same vehicle from this company. All have been defective, we own the largest shop in our area and have lost money because we have had to install and remove these transmissions once every 2 weeks. Don't even last 200 miles, and are slipping and jerking. Isn't good for business when we have to keep telling our customer I'm sorry I can't give you back your truck because the new transmission is also bad. This job is for one of the largest electric company's in the world, would hate to lose them over this issue. Honestly wish I would have read these reviews before ordering this from Auto zone.