Hi,
You mentioned that the Shifter vibration is tied to drivetrain load (especially in D, 2.5–3k RPM).
You also mentioned that there wasn't any vibration in manual mode this means that the transmission’s hydraulic control or torque management behavior changes something.
Since you're getting vibration over bumps that transmits through the shifter it's probably some form of mechanical linkage or mount compliance issue, possibly related to drivetrain alignment or grounding.
That “feeling every bump through the shifter” almost never comes from inside the transmission — it’s nearly always a driveline isolation issue, especially mounts or bushings between the transmission and differential.
Here are somethings you can check:
1. Rear differential bushing or subframe bushing wear
These bushings can transmit a ton of vibration through the driveshaft if they allow excessive differential movement.
When the drivetrain torques during an automatic shift, the driveshaft may flex slightly and send that vibration up through the transmission tunnel into the shifter.
Manual mode reduces these torque jolts which probably caused the vibration to disappear.
Test: Jack up rear, grab differential, and try twisting it — if it moves noticeably, that’s your culprit.
2. Driveshaft carrier bearing (center support bearing)
A worn or partially collapsed bearing allows vertical driveshaft play, especially when suspension load changes (speed bumps).
You’ll feel it most when the rear suspension unloads or loads — exactly like your “sharp bump” scenario.
Test: Look for cracked rubber or slop at the center support; if it’s dry-rotted, that’s likely it.
3. Transmission crossmember or subframe alignment
Even though you replaced the mount, if the crossmember is slightly misaligned or the bolts are torqued unevenly, the transmission can “pivot” slightly on bumps.
The fact that it improved for a week after the last mount change might mean the new mount temporarily sat correctly before settling.
4. Internal valve body / TCC (Torque Converter Clutch) behavior
In rare cases, a hydraulic resonance in the transmission (especially in D mode) can cause a noticeable vibration through the shifter linkage.
The fix often involves a valve body service or updated solenoid calibration (done by a transmission specialist).
However, since you feel it on bumps too, this is less likely the main cause.
5. Ground strap or exhaust contact
Check the engine/transmission ground straps and exhaust brackets — if any are loose or missing, the drivetrain vibration will have no proper path to dissipate, and it’ll travel through the shifter instead.
I hope this helps!
P.S - Chatgpt was used to help write this.
