This problem has bugged me on the Foz since 2023 when we bought her, and then the Leggy started doing it too.

Models;
Forester SG 2.5 xt auto
Legacy Gen 4 3.0r auto
Both > 100k miles

Symptom;
A transient pulsing vibration felt through the floor, and most noticeable through the accel pedal.

Conditions;
Light steady throttle, slight loading like driving up a small incline, around 20-30 mph. It's worst here, and was more of a pulsing vibration.

Hard accel high speed a rapid vibration through the body and accel pedal.

Cause;
I'd convinced myself it was the torque converter, but after a lot of investigation, it's actually the T/M pitch mount. The small end bush had elongated such that the metal collar could rotate and had back and forth freeplay.




Fix;
A new one! Thankfully they're cheap and easy to fit, particularly on NA as it's just the airbox to remove. I bought a genuine part from partsouq for the Foz, but will probably just buy a Febest part from eBay for the Leggy. Subaru have an updated PN, as below, a countermeasure part I wonder......

41040AE010 which replaces 41040AE000

 

With nothing to lose, I' trying a "free" fix of the old Fozzy part for the Leggy. I pushed the insert out, packed the hole with Sikaflex and pressed it back in. Let's see what happens!

 

I used sikaflex 221 and it's worked on the Leggy. Will see how it lasts, but it's a 'free' fix for now, so happy days.

Interestingly the Foz and Leggy pitch stops are slightly different and it didn't fit. The foz one is about 5mm longer and the big end bush is separated at the 'sides' whereas the Leggy one has the sides bonded to the housing.