I bought my son a 2009 AWD Lincoln MKS with a 2 year warranty for up to the purchase price about 15 months ago with 169,000 miles. He has put 6,000 miles on it and between 3rd and 4th gears there seems to be a transmission issue where it feels like the gears are slipping. No transmission codes appear and my mechanic replaced the ignition coil and put in new spark plugs. I also put on 4 new tires since they were not evenly worn hoping that may help the issue since it is an AWD. It has not. My mechanic now thinks it may be the torque converter, but recommend replacing the entire transmission. What do you think? The warranty may cover the torque converter, but not the entire amount of the transmission.
If the torque converter is failing, the trash it is shedding have a very good chance of ending up inside the transmission causing that to be the next part that fails. If, indeed, the trans is slipping between 3rd and 4th gears, a torque converter change won’t help that at all. The slipping eventually destroy the transmission anyway. And when the trans is rebuilt, the torque converter should be changed because it will be full of trash.
Given that you this car with 169K miles on it, what you are experiencing is completely expected. Especially if the transmission fluid and filter have never been changed. If you did not get a pre-purchase inspection by a mechanic not affiliated with the dealer, maybe they would have caught this.
I think your choices narrow down to; Replace/rebuild the trans AND replace the converter, or scrap the car. There is nothing in-between.
It may be too late to do this but I would suggest having the transmission serviced; meaning change the fluid and removal of the pan., With the pan off one can see if there is any debris or excess grunge from the clutches and then make a decision about a possible transmission replacement.
Your guy “thinks” it may be the converter and suggests replacing the transmission. That seems like a pretty expensive thought at this point.
I drive Fords for the most part and find that they’re kind of touchy regarding aged transmission fluid. If fresh fluid and a new filter does not cure it at least you’re not into it for more than a couple or 4 hundred dollars; all depending upon locale, shop rates, and so on.
As for the uneven tires the cause of that could be whatever depending upon the wear pattern. The problem here is that the new tires are also going to wear unevenly.