[Amarsir]

Hmm, how would I know? I didn't experience any power problems. The symptoms were an easily-ignored "shhhhh" sound, followed by a feint burning rubber smell in the middle of a long drive, and then once back from said drive (when it was obvious something was wrong) the drag was sufficient to overcome idle engine speed so that I couldn't pull away from a light without giving gas.

This led me to mistakenly conclude it was a stuck brake. The only counter-sign (after stopping to test by applying then releasing the parking brake) was a bit of a clunk on accelerating, and that was not an experiment I was anxious to repeat. When the shop looked the next morning they said unambiguously that it was the differential, which I assume was obvious from boiled-over fluid.

I have asked them to triple-check that the differential was the cause and not a symptom, and I have reasonable trust in their competence, but obviously I'm afraid of replacing a differential now and learning I need a whole transmission in 2 months.