Hello,
My 2012 Toyota Highlander with automatic transmission, 4WD, and 110,000 miles shudders significantly when decelerating (not braking) from @70 mph. You can feel the shudder slightly starting @65 mph and increasing to and through 70. It becomes much more prominent when lifting off the accelerator until the vehicle slows below 65. It is felt slightly in the steering wheel, but also generally felt throughout the vehicle. As the only troubleshooting step I could think of while driving, I got it up to speed and then put it in neutral - nothing changed.
I personally checked the driveshaft (front to rear), CV axles, steering components, and looked over all four wheels. I replaced the driveshaft last year, but that was due to a vibration felt on hard acceleration. I also ensured all four tires were properly inflated and looked them over for unusual wear or damage.
I took it to the local repair shop but they would not take it to 70. They did look it over and put it on the lift - basically checking everything I had. They also stated that they checked the engine mounts, but only after I mentioned it. I plan to recheck that this weekend.
This is my wife's vehicle that she drives daily at those highway speeds. What else can I do?
Thank you.
All right check the transmission and motor mounts and pray one of them is gone because if not your transmission would be wearing out internally
Have another mechanic look at it too. Might catch something the other missed.
So many mounts and components in a drive train can cause vibration.
Fingers crossed it's not the trans.
I'm a bit embarrassed about this, but I used Slime Thru-Core on the front left tire. I was fighting a slow leak on that tire for months and figured I'd give it a try - TPMS sensor safe, lots of good reviews. One important instruction I failed to read is that you need to have the tire repaired and the Slime removed within 100 miles - doesn't say why, but my guess is the stuff pools and hardens. In my defense, the wife said the vehicle was doing the shudder thing for "a couple of days", so before I used the Slime, and I did not find any info about Slime causing tire balance issues. This is different from the green stuff.
Anyways, talking it through with a mechanic friend, he suggested putting the spare on and road testing it - sure enough, no shudder. I took it back to the same shop that didn't find anything and had them unmount, clean, and remount the tire and balance the wheel. The tire guy said the inside of the tire was a mess and it took about 30 minutes to clean it out. Lessons learned - read instructions, go with the obvious cause (despite what the wife says), and maybe find another shop. They also failed to find the leak in the tire when I took it in months ago.
Thanks for the replies and many thanks to you Scotty. BTW Scotty, thanks to your video, I rebuilt the AC system on my daughters '96 Civic (her compressor seized and basically came apart), including purchasing all the parts and equipment, for hundreds less than a shop would have charged.