" It is only 0.2miles and we would be going down about 400ft. If I did my math right that is about a 2000ft elevation change in 1M. So the question is...is that doable? How do you determine something like that?"
As the second poster indicated, slope is often not indicative of passability. Much depends on the nature of the terrain; perhaps the rock is wet and lichen covered or there are short vertical cliff bands to be negotiated, or loose talus. The time of year has a huge bearing on conditions, especially on north facing slopes. Your level of fitness, comfort with exposure and technical capabilities should also enter into your decision. Almost every pass in the Sierra is described in one guide book or another. Look for the pass in question in Secor's Rocks and Routes guide to the Sierra. You should be able to find what you need there. Also look for trip reports as your departure date approaches and be prepared to use an alternate route if necessary.
Case in point up here in the Cascades. Mailbox Peak gains 4000' in 2.5 miles and yet is considered merely a strenuous day hike. OTOH, coming off the summit of Mt Stuart there is an innocuous looking slope of about 20 degrees that, when ice covered in spring-early summer, can, and has, taken unwary, though highly experienced, climbers on life threatening rides(including two with I am personally acquainted) due to underestimating it in a mood of elation coming off much more difficult technical climbing.
A final observation: Plan a bypass to any section of your hike that is even slightly questionable and your chances of having a great trip will be greatly enhanced.
Best of luck!