Does the Merc alignment tool fit into the spline coupler/carrier bearing on a Stellings box?

Doesn't seem to fit on mine. Face of the splines are flat with no obvious pointing or wear.

Planning to talk to Stellings technical assistance on Monday.

I always found the Alignment tool to be very tight and the only way to set the alignment on those things is to put shims under the carrier bearing which only aligns it one direction, vertically. You can't do anything about parallel or horizontal alignment unless you have custom tapered shims made.