Last summer I purchased my 2011 XC90 executive with 155K miles. I was told it had a “stutter” when it was cold and had done this for 3 years and 35,000 miles. It was warm when I bought it and it worked fine so I bought it. The car was garage baby gorgeous and the price was right or so I thought.
As the cold set in late summer, so did the vibration. This vibration occurred in the front passenger area and came on with mild acceleration going up a hill in high gear, in other words, a heavy load on a lugging engine. It felt like hitting a rumble strip. It disappeared with coasting, further acceleration/downshift, or just aggressive driving. It got much worse in cold weather but it didn’t matter how warm the engine was. No codes or misfires in VIDA. I looked up rumble strip and found “Torque Converter Shudder”
Now the car had my attention. I reviewed the Dealer records I got with the car and called the Dealer for the rest. Here it gets interesting. The car had been to the dealer five times for this complaint over three years and always in the winter. They could reproduce the “shudder” and had serviced the transmission fluid twice, updated the transmission software twice, changed spark plugs, fuel pressure regulator, fuel filter and had disconnected the propeller shaft all of which did not change the vibration. They finally recommended that the transmission be replaced which the PO refused and instead just kept driving it for three more years. Somehow the PO forgot to mention or give me the records for the Volvo dealer visits with regards to the transmission. The Dealer did not list any engine, transmission or other codes/findings to back up the transmission failure diagnosis.
Now I was getting nervous. Had I bought a boat anchor? I did what any idiot would do. I quickly flushed the transmission with 14 quarts of Aisin fluid along with a shot of Shudder Fix. This did not help. Buyer remorse was beginning to rot my soul. Enter artificial intelligence.
I began to describe in detail all the symptoms and history of the vehicle in ChatGPT. It was like going to an automotive priest. It comforted me and did not think the transmission was at fault but rather felt the motor mounts, CV axle or suspension was the culprit. Since I had VIDA and was paranoid, it walked me through setting up recommended VIDA parameters for monitoring for torque converter shudder(my biggest fear). Next I uploaded multiple screenshots of the graphs of these parameters during the shudder and ChatGPT felt they were normal and that this ruled out a transmission problem. Next it suggested NVH(Noise Vibration Analysis) and I caved in and bought the $100 App for my Iphone. This was pretty intimidating for a DIYer but was pretty easy in execution. I just set the phone in my console phone holder and ran the NVH app while bookmarking when the vibration occurred. I uploaded a screen shot of the results which ChatGPT interpreted. The NVH app reported “Second Order Tire Vibration” during the most violent of my shudders. ChatGPT said this ruled out CV axle since that would be a third order tire vibration or a separate driveshaft vibration. This result also ruled out engine, engine mounts, and transmission since that would generate an engine vibration. I was told to check the tire/wheel for being out of round and then to focus on the suspension particularly the struts and control arm bushings. I had just had new tires, power balancing and an alignment so that ruled out tire/wheel. I was informed that laxity in the suspension allows “oscillation” in the wheel resulting in the second order tire vibrations. It walked me through manual testing for wheel bearing, ball joints and tie rods. There were some cracks noted in the control arm bushing. ChatGPT recommended that I start there and then do the struts if that didn’t work. I first did the control arm bushings which took away about 80% of the vibration. Replacing the struts, strut seats, and strut bearings removed the rest of the vibration and the ride now is like that of a new car with a grateful, relieved owner.
This is my second high mileage XC90 and I love it. On my 2006, I DIYed all the frequent failure parts and gradually eliminated all the noises, vibrations and misbehaviors of my car. I feel I replaced a number of things that didn’t really need it. Yes, I would have probably got there on this new, old car by doing all the maintenance that was due. However, I was about to desperately resell it as a known transmission issue or salvage it entirely. I mean who am I to argue with five separate Volvo dealer evaluations. I would have never have gone this route without artificial intelligence. Plus I really enjoyed sorting this with ChatGPT and NVH. I’m sinfully delighted that the Dealer was wrong. Plus I’m finding as I age that I more enjoy thinking about mechanical work than actually doing it and artificial intelligence really accommodates that.