Replacement bottom bracket for Shimano XT FC-M785 crankset
TL;DNR - I recently had exactly the same problem with my 3x10 XT MTB and handed the job to the LBS.

You need to be aware the great thing about standards is when you can't find one that suits you make a a new one. The Cycle industry took this to new extremes since the early 2000's with regards to Bottom Brackets. The BB matches the crank set to the frame, so you half of the equation knowing the crank set. The manufacturer and all my normal goto references for bike specs are silent on the BB standard of the frame.  

If the BB is press fit, its probably BB30. Have a look on the lower seat tube - some manufacturers helpfully print use information on BB.

If press fit, this is one job that might be better left to your LBS - you probably won't have the correct tools to do it yourself, correct tools are expensive and DIY cobbled together tools can easily stuff a frame. With the correct tools the LBS has, it is a 30 minute job, and that 30 minutes comes with years of experience.