Those are interesting symptoms.
Here's a quick and easy way to verify that your transmission input shaft is not bottoming out in the crank's pilot hole.
Try loosening the 4 bolts that hold the transmission to the bell housing and see if the transmission moves back by itself. If a gap opens up between the trans and the bellhousing, you likely will have to cut/shorten the input shaft.
I had to shorten the input shaft on my 833 to allow it clearance from the bottom of the pilot hole in the crank.
Good idea. Although I would expect they separate slightly. If a 0.030" gap opens up, is that a positive result? How much fore/aft play is in the input shaft? Maybe a better test would be to loosen the bellhousing bolts so the bell can move back 0.060-0.080", not enough that the starter wouldn't engage or come out of its pilot hole, and start it up to see if it shifts better. Now that would be a positive result. Any reason that wouldn't work?
