I haven't really had any problems with my Ford dealer, but we've had issues with two Jeep dealers.
The first was on our 2012 Wrangler. This was the first year they put the 3.6 in the Wrangler and the factory that built the Wrangler engines had an issue with the tooling used to machine the heads for the valve seats. By the time we had the issue, everybody in the Wrangler world knew about it. The only real symptom of the problem was a code P0304 and we got it at about 18k miles. Took it to the dealer, they had to keep it over night to do nothing but scan and clear the code. When my wife picked it up she didn't make it a block before the light was on again, so she took it right back. They made her get an appointment to come in and get the computer reflashed. I called them and asked why they didn't just put a head on it like we all knew they needed to. They denied that there was any such problem, so when we took it back for the reflash I printed off the service bulletins and took them to them. They still denied it. Kept it two days to reflash the computer. The light was on again a block later. Took it back again and they wanted to replace the PCM. I think they had it about a week that time. Still didn't fix it. Took it in a 4th time and the service writer tells me he thinks it may need a cylinder head like it was his great detective work that discovered the problem. By this time the heads were on national backorder for 4-6 weeks and they wanted us to drop off the Jeep and leave it with them the whole time. Nope. Not gonna happen. He finally agreed to call me when the head got there, but I had to call them after nearly two months and they told me the head had been sitting there waiting on us. Finally got it taken care of and never had any other significant problems with the Jeep or the service department.
In 2016 we traded the 2012 in on a new 75th Anniversary Wrangler at the same dealer. The first purchase was a great experience. The second was a nightmare, so we went to a different dealer when we needed service. That happened at about 56,000 miles when I serviced the rear axle and chunks came out. I saved the bigger ones, which were obviously pieces of spider gears, and put them in a ziplock bag to show the service writer. My wife took it in to another dealer, told them what I found, and showed them the pieces. They kept it for three days, drove it 0.2 miles, and told us they didn't hear anything but tire noise. There was no tire noise and the axle wasn't making any noise either. Before we picked it up I called them and asked them about the chunks I found. They said it was casting flash and nothing to worry about. I asked them if they commonly saw casting flash the size of marbles that was machined, ground, and hardened. All he would say was that there was nothing wrong and they weren't going to do anything with it. I was just supposed to keep an eye on it if it got worse. I suspect he was just hoping it would make it another 4,000 miles until the powertrain warranty expired. I took it home, popped the cover off, took pictures of the spider gears broken all to hell, put it back together and took it back to them. This time they agreed to fix it and it only took 3 weeks. Idiots. If I had known it was going to be 3 weeks and such a PITA I would have just bought a TruTrac and been done with it. Then when we got it back, the XM radio didn't work. Come to find out they had swapped our radio while they had it and stuck us with all of the fees to Sirius to get it reconnected. I suspect our radio was riding around in one of their employee's cars with what they thought would be a year of free XM radio.
