I have a mechanical question on a 2018 Buick Enclave, 110K miles. My wife's car has a shake/vibration right at the 1800-2000 rpm range once you get into 2nd-4th gears. This happens under general/casual acceleration when casually driving. It's a very apparent shake. It doesn't happen if you are accelerating hard and get into the 3K-4K rpm's. Our mechanic recommended a fuel injector cleaning/flush and that didn't improve anything. The car shifts fine and starts the shaking after it changes gears and is in the 1800-2000 rpm range. I've been told probably the transmission, motor mounts, or timing chain. Motor mounts would be the easiest to check, but the other 2 would be more costly and involved. My mechanic put it in drive with his foot on the brake and pushed the gas, and he didn't think it was the motor mounts from that. Just curious what THF mechanics think it could be. Thanks in advance!!

Just a wild card, she may have a bubble in a tire. Have a tire shop put it on a lift. You often can't see bubbles with the car on the ground. My truck did this a few years ago. After a few mechanics it took a tire guy to find it. Best of luck sir!

It shakes at that RPM, regardless of what gear it’s in? Possible drive shaft imbalance or a bad U Joint. had that once in an English car. Mechanic blamed it on bad shocks, so I shot him. Well…I imagined shooting him. Took me a while to really find the problem.

motor mounts?

Yes, it will shake in any gear from about 2nd or 3rd, to highway gear at 70 mph. When running 65-70 mph in the 1900-2000 rpm range, you really feel it shake. The shaking starts after it changes gears. It will change gears smoothly into 2nd or 3rd. It changes gears, then starts to shake during acceleration. Once you get past 2000 rpm's, the shaking goes away. Then it shifts up to the next gear smoothly, and starts to shake at 1800-2000 rpm's, then goes away. Then shifts up to the next gear smoothly, then shakes again in the 1800-2K rpm range. The shaking goes away and comes back depending on the RPM's during acceleration. It only does it at a mild and casual acceleration. If you put your foot in it, and accelerate more aggressive, the shaking is not there. When on cruise control running 70 mph at about 2000 RPM's, if you come up to a hill it will really shake when it gives it some gas to maintain speed. It gets annoying.

The 2 mechanics I use are not sure what it is. My next step is to just take it to a dealership.

Sounds like the torque converter.
A call to the service writer at the dealer is free. If he’s good, he’s probably already familiar with this issue.

Best guess without looking at scantool data, based solely on your description of the complaint: Torque converter clutch glazed or delaminating. At a minimum you'll need to replace the torque converter and Flush cooler and lines, but a remanufactured trans will come with a 3 year, 100,000 mile warranty if that makes more sense financially to keep the vehicle in lieu of a new car payment.
GM World Class Technician, Transmission specialist for Sewell Cadillac Dallas.

Torque convertor shudder is the first thing that comes to mind

Time to trade that sucker in.

Sounds like it's gonna shake $3-4K out of your wallet.

LMAO!! True!!

Thanks for the help guys!!

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