Yup, everything Bruce just said. I am just now tearing into 1525. She has 5K miles on her and the transmission came out last night. I figured I would wiggle the gears around and if all was snug, I'd put it back together and forget it. Well, they weren't and I didn't.
The two gears I measured just for grins, had 0.004" clearance and the other was 0.006" clearance. According to Machinery's Handbook, a bearing in that size, with a constant supply of oil, should only be about 0.001-0.002". And mine weren't wobbling that badly.
It really is amazing that the vendor couldn't hit the tolerances closer than that. The shafts are precision ground--a technology where they regularly maintain tenths of a thousandth tolerance in production. The gear bushings are probably reamed to size--again--a very well known, precise process. The vendor should have done better than this.
Even if the transmission doesn't lock up, sloppy clearances mean that the gears won't contact on their designed pitch contact circle. That will cause premature wear on the gear faces.
When I'm done with this one, I will probably tear into my other one and do it as well. Id rather ride than wrench but, when they need it, they need it.
