My recent experience says Yes - you can determine a few things out of the car / The way to generally test the gears is to run thru the shift pattern and confirm all are achievable with out anything other than the shift ball at the console and do this by bare hand / no tools. That typed,... you will obviously not be able to confirm condition of syncros and bearings much less dog teeth and sliders. To do that requires opening up the box and taking out the gear stack / a not to difficult task - at which point most-all is revealed. In my case (no pun intended),... I bolted up the box insight unseen, and drove the sucker for three years and am still driving it on a powerful 3 liter 6. Sometimes, one gets lucky and the 901 is extremely forgiving in most non-race applications. It is easy to R&I so I say put the box in and adjust all linkage with new bushings and cone screws and see what you have.
After the clinic with Dr. Evil a few weeks past, I now have another 901 as a spare with all good innards and a flipped H for higher speed at lower revs in 5th on my 6 3.0.
I will insert that transmission and sell the good box I currently have some day soon for something to do - but my current 901 is proven to be just as good with stock gearing - in my car currently / hope this helps.....
Sidebar: From LSU originally and missing good food and people out here in LaLa land..... Eat a dozen or two for me next time in Mandina's or Tejaques.
