My partner and I recently traversed the east ridge of Mt Lyell from Donahue Pass. Trip report here:http://www.summitpost.org/full-east-ridge-of-lyell-from-donahue-pass/908542

We have been unable to find any information about this traverse in text or online both before and after our adventure. We have been wondering when this route was first climbed and what grade the first ascensionists might have given to the route. Anyone have any leads?

Evan

kaos14,
Congrats. Nice job.
FWIW,
Secor (2nd Edition, pg. 395) has two entries on the East Ridge on Mt. Lyell:
1. East Arete (no FA info)
2. East Arete from Marie Lakes: FA July, 3, 1977 by Sonny Lawrence, Diane Rosenstreter and Ian Clarke.

Secor also mentions further reading on the East Arete:
Sierra Classics, Evergreen, Co. Chockstone Press, 1993, pgs 254-255.
I seem to have misplaced my copy so I wasn't able to look for traverse info in Fiddler's book. Maybe the book is online through Google Books?
I realize the above doesn't answer the question about the FA for the full traverse, but maybe Sierra Classics might have what you are looking for?
Best,
JM

UPDATE: I just found my copy of Sierra Classics, the page on the East Arete doesn't have any additional or revealing information about an extended traverse to the East Arete. It just has info on the East Arete proper. Lo Siento.