will the 4 speed bolt to the under drive?

[Matt]

I have a aa 4 speed and would like to use it instead of my 3 speed.

Matt

[Stakebed]

if i remember right, the reason for the 4 speed was 1st is essentially a granny low thus no need for the "dual high" - 4th gear is the same 1:1 ratio that 3rd gear is

I may be wrong tho

[Matt]

Thanks that makes sense.

Matt

[Neil Wilson]

The dual high (or dual drive) underdrive can be installed behind a 4-speed with a couple of parts which include:

AA-7085-B rear bearing retainer - replaces the star shaped rear bearing retainer and allows the u-joint inner and outer housing to be used.

A-7095-C u-joint - front knuckle fits the 4-speed and rear knuckle fits the 1928/1929 coupling shaft, dual drive, or Warford.

I have an AA-7085-B rear bearing retainer to sell but no u-joint.

Your AA should already have the 1928-1929 coupling shaft rear support (used for the 1928/1929 coupling shaft, dual drive, or Warford).