In my collection of torque tube pieces I have only one steel washer. Would I put it on the inside or outside of the seal?
The screw on retainer cap requires two washers.
One washer on each side of the oil seal.
The inside dimensions of the back of the retainer cap is larger than the inside dimensions of the oil seal.
When the retainer cap is screwed on the oil seal wants to bulge out the back of the retainer cap.
Rather than bulging downward into the torque tube.
The inside dimensions of the washers are the same as the inside dimensions of the oil seal and the outside dimensions of the torque tube.
Therefore the oil seal has no place else to go except into the torque tube.
One other thing, the oil seal looses its bounce back tension after awhile.
That is one of the reason why the retainer cap loosens.
Call
Northwest Transmission Parts ask for John.
They will have the washers and all the parts you need to fix your truck's leaking problem.
They make rubber and cork retainer cap seals I prefer rubber.