DO you mean inner TTB stuff or the outer hubs and such?
None of the TTB stuff will work on the waggie except for the carrier. TTB is HP(and the gears, etc. will work on HP44 SA stuff) and the waggie is low pinion. The spindles, etc. will work for some applications but not really worth it IMO.
Elliot, we have swapped a bunch of SA HP44s into TTB trucks.