What happened is that Volvo Penta discontinued supplying the DPH-A with new applications and went to
the DPH-B. The big difference between the A and B revolved around the lower gear set in the lower unit
prop shaft. So if you have an A originally you had to replace it with a DPH-B.
But after a while, Volvo Penta changed the DPH-B to the DPH-C and then to the DPH-D and then to the
DPH-E. Many but not all of the parts are interchangeable with the big difference being internal with
the gear sets.
So for example if you have a DPH-B complete outdrive the original part number was 3862822 but Volvo
Penta has replaced this with a DPH-D 22079438.
If you wanted to replace the DPH-B upper unit 22079926 you could still get the same DPH-B upper unit.
This upper unit is the same for the DPH-B, C, and D, but not the same as the upper for a DPH-E.
But if you wanted to replace the lower DPH-B 3801127 it supersedes first to a DPH-C lower unit 3862814
which then in turn changes into a DPH-D lower unit 22079940 which in turns into a DPH-E lower unit 23493469.
Now all the units from the DPH-B through DPH-E will fit on each other’s transom shields even though the
DPH-E uses a different transom shield and the DPH-A transom shield can only be used with a DPH-A outdrive.
So the part number you gave 23493456 is for a complete DPH-E drive with a 1.69:1 ratio.
The part number 22079926 is the upper gear for a DPH-A, DPH-B, DPH-C and DPH-D (used to be 21433429
then changed). The DPH-E has a different upper gear number of 23493463.
The final part number you gave was 22079940 which was originally the lower unit for the DPH-B, C, and D
which now changes into a 23493469 which was originally only for the DPH-E but is now the lower unit
for the DPH-B, C,D, and E.
There is no difference in performance between any of these drives and visually they look the same.
The improvements are internal and the later the drive part the stronger and longer lasting they are supposed