Help ID this Over/Under Drive?

[englishdavid]

Picked up this flathead overdrive unit that appears to mount somehow in a Ford torque tube.
Has 6 spline in and out, operated by single lever.
Has no casting marks, or maker marks other than on the UJ.
Anyone ID it?

Its about 33" long

Asked on the HAMB, some people think its for an AA Truck??
Thanks
David

 

[columbiA]

Looks like a dual-high aux trans for a 28-29 "AA"truck.It is direct & underdrive.

 

[Chris Haynes]

Yup. Definitely NOT an overdrive.

 

[2manycars]

Definitely a 29 AA dual high, direct and under drive. I have some in the barn.