Transmission noise / vibration on decel only

moose09876 · 07-12-2026, 04:40 PM

One last post just checking to make sure I'm not missing something before spending the big money. My countershaft bearing was bad when I bought my '13 135i, so I swapped in a GS6-53BZ. This transmission has a very low pitched grumble / vibration above 2k RPM, but ONLY on decel, clutch out, in gear, and it doesn't happen all the time. It seems to sometimes be better temporarily if I just thrash it through the gears, but it will come back. It's also not as bad when the trans is cold. There are zero issues if the car is maintaining speed or accelerating. If the vibration is happening and I push in the clutch, it immediately stops.

Anybody have other thoughts?

greywing.wip · 07-13-2026, 10:40 AM

How is health of the engine/transmission mounts?

I'm chasing something similar (jerkiness/lugging on low gear decel clutch out).

So far I've changed out transmission mounts, guibo, center support bearing is still healthy; so next step here is motor mounts.

moose09876 · 07-13-2026, 01:07 PM

All new mounts in 2023. The gs6-45bz did not have this vibration.

07-12-2026, 04:40 PM	#1
moose09876 Second Lieutenant 329 Rep 210 Posts Drives: 13 135i mt 20 Chevy 16 R1200R Join Date: Oct 2013 Location: Indiana iTrader: (0)	Transmission noise / vibration on decel only One last post just checking to make sure I'm not missing something before spending the big money. My countershaft bearing was bad when I bought my '13 135i, so I swapped in a GS6-53BZ. This transmission has a very low pitched grumble / vibration above 2k RPM, but ONLY on decel, clutch out, in gear, and it doesn't happen all the time. It seems to sometimes be better temporarily if I just thrash it through the gears, but it will come back. It's also not as bad when the trans is cold. There are zero issues if the car is maintaining speed or accelerating. If the vibration is happening and I push in the clutch, it immediately stops. Anybody have other thoughts? Last edited by moose09876; 07-12-2026 at 05:21 PM..
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07-13-2026, 10:40 AM	#2
greywing.wip @greywing.wip 67 Rep 70 Posts Drives: 2012 135i M-Sport 6MT Join Date: Aug 2025 Location: SF Bay Area iTrader: (0)	How is health of the engine/transmission mounts? I'm chasing something similar (jerkiness/lugging on low gear decel clutch out). So far I've changed out transmission mounts, guibo, center support bearing is still healthy; so next step here is motor mounts.
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07-13-2026, 01:07 PM	#3
moose09876 Second Lieutenant 329 Rep 210 Posts Drives: 13 135i mt 20 Chevy 16 R1200R Join Date: Oct 2013 Location: Indiana iTrader: (0)	All new mounts in 2023. The gs6-45bz did not have this vibration.
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