Allison Transmission Failure
Here are the parts of the main pump of the Allison 4000 MH transmission stacked in the order that they would be assembeled.
The top part is a bushing, which we will call Part B
The second shinny part down is the shaft, which we will call Part S
The third part down is the inner gear of the pump which we will call Part I
The fourth part down is the outer gear of the pump which we will call Part O
The fifth part down is the pump housing which we will call part H
The sixth part down is the tourqe converter pump assembly which we will call part C
the part behind is the wear plate that goes on top of all of this after it is assembled which we will call part W.
The pump is turned at all times when the engine is running by two tangs that are located on part C and engaged in the slots of part I. Part B is inserted fully into part I and rides between part I and the part S. The tangs on part C are severely bent due to under power disengagement with part I. These tangs would normally be in the slots of part I, riding between part I and part B. Note that there are humps on part B which which also engage with the slots on part I thus causing it to turn with part I, and rotate on part S.