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[JimmyStinkpickle]

Hi all, I am currently rebuilding the mainshaft for my DAM5626 gearbox and first gear refuses to fit over the new needle roller bearing from Minispares (AAU1815). There is a slight amount of play when I lightly pull the bearing against the journal. I measured the outer journal diameter of the top hat and it is 32.15mm. Do I have the wrong size bearing or is there only one? I am at a loss and would appreciate any help/advice. Thank you!

 

Some things worth mentioning:

When installing the top hat, it was a tighter fit than I was expecting and had to be drifted home almost from the top of the mainshaft. Also, the bottom of the old bearing had melted off, exposing one end of the rollers as you can see in the 3rd pic. It split apart when I tried to refit to the top hat. Not sure if relevant to the issue.

 

 

 

[Spider]

If the original bearing is in OK order, reuse that. They very rarely need replacing. With all these needle rollers under the gears, in use, they only spin when unloaded and don't spin when loaded, so wear is negligible.

The late Mainshafts are often oversize, the inner race is a press fit, but on some of these shafts, it's beyond crazy how tight they can be. This of course does lead to the inner race expanding. They are also too tight where the Mainshaft double row bearing fits, which often leads to the bearing coming apart when trying to disassemble the box later, ruining an otherwise good bearing. I bring them down on size in the lathe using a diamond lap.