MrCreosote

I have a lot of T10 stuff, gears, cases, shafts, etc. and found a strange non-spline reverse idler gear that used a 4-lug connection.
I checked my B-W catalogs and it appears for 57-60, they used a 4-lug connection before they went to the spline.

However, the width of the spur gear idler is narrower than all the other idlers and reverse gears that I have - except for one reverse gear that is narrow and matches the 4-lug narrow spur.

THE PROBLEM is that both of my old B-W catalogs say the same reverse gear part T10-46A is used in ALL T10 and Super T10 transmissions.

So there are 2 possibilities:

1. What I think are T10 parts are not, or
2. They are indeed early T10 parts, but the B-W parts manuals are wrong.

Does anyone have a 58 factory shop manual with a good pic of the reverse and idler gears - it's possible to visually see if they are narrow?
(or does anyone know for sure what I have?)

Here's a pic of the 4-lug and spline versions:

The LH is the 4-lug. Note that the idler stack height is the same for both versions and the idler shaft bore diameter is the same. The reverse slider groove is the same distance from the hear side of the spur gear - the difference is that about 1/8" of material was added to the "face" of the LH reverse gear.