Speed Lube

SpeedLube changed the oil in the rear differential and now it is having trouble turning.On February 27th, I took my 2010 Ford F150 into SpeedLube to have the engine oil changed. The technician told me that I also needed to have the rear differential fluid changed because it looked milky. He asked if I had the truck submerged in water and I told him that it never had been. Within a couple of days, I noticed a shuddering in the rear end when turning that I have never had before. I asked a friend, who is also a mechanic, his opinion on the shuddering and he said that it sounds like the clutch paks are rubbing together in the rear end, which could be because the wrong fluid was used or additional friction additive was not added. I called up to the SpeedLube to discuss the problem and he told me to bring it back up there so he could look at it. I am unsure who I spoke with, but whoever it was said that they also had a Ford truck and they haven't ever had this issue.I took it back up to SpeedLube on March 23rd. They "removed the gear fluid and replaced it with Mobil 1 Full Synthetic 75-140 gear oil & added a limited slip additive". (I asked for a receipt for the work performed and they said they could not print a receipt but would write down what they did. The hand written note is signed by 2 employees.) They told me to give it a couple of days to let the new fluid work into the rear end. However, the shuddering did not stop. I took the truck back up to Speed Lube on April 7th. I discussed the problem with the store manager and explained that after I looked in the manufacturer's manual, it stated that the fluid is a lifetime fluid and should not have been changed. The manager told me that is not what CarFax said. (Not positive if he said CarFact or Carfax.) He said this must have been a problem before they changed the fluid and I just didn't know it. I told him that it was never a problem before the fluid was changed. Prior to them changing the fluid, it had never once shuddered or made any noises when I turned. I also asked when the district manager was going to call me because I had been told twice already that he would call me. The store manager said that he relayed the message, but he will tell him again. The store manager said that I probably have this issue because of all of the off-roading that I do. I informed him that I do not do any off roading in this truck. Then he said that it is probably caused by me towing alot of things. I told him that I have yet to tow anything. I left the truck for him to drive to see if he could identify the problems with turning. When I called him back hours later, he said he did not find a problem with it. I returned to Speed Lube and we drove it together with an employee of the neighboring muffler shop. The shudder and noise was obvious and the store manager said that he did feel it. The muffler shop employee also said that he felt it, but he "did not understand why putting the wrong fluid in there would cause it." He said that I should bring it back in tomorrow (April 8th) and we will figure out what to do.I received a call from [redacted] on April 8th and he said he had been doing some research and had found that trucks made between 2009-2012, with more than 84k miles on it have had similar issues as this. He told me that he had spoken to the district manager and he was told to go over the information that he obtained online with me. I then asked when the district manager was going to call me since I have been told for several days that he was going to call. [redacted] then said that he never told me the district manager was going to call me. I told him that it not true and I have a witness that heard him say that he didn't know why the district manager hadn't called yet and he would tell him again.It is very frustrating to be given so many excuses and be given the 'run-around'. I did not go in to Speed Lube to have anything but my oil changed, but trusting their recommendation, they changed the differential fluid and now my truck is in worse condition than before.Desired SettlementI would like to take my truck to a Ford dealership and have them look at the rear end differential. I would like for SpeedLube to cover any repair costs that are attributed to the rear differential fluid change.