Hi to all,
I am in the process of resealing my 4 speed and have removed the long (2+2) tailpiece to replace seals and gasket.
My question is with the Spedo drive gear. Does it just slip over the output shaft, I do not see how it would lock to the shaft and what would prevent it from not spinning with the shaft or moving along the shaft.
Is this correct
Yes. It and the Oil Pump Drive is held fast by the clamping force applied by the Companion Flange Nut. Accordingly, its important that this nut be tight. There is no torque specified for this nut by Jaguar (that I know of), but I use the same setting as the differential Companion Flange Nut (120lb ft - 140lb ft). This is well short of the plastic deformation zone of this size thread, but reasonably tight.
Rather than being concerned about the Speedo Drive Gear slipping, I would be more concerned with the Oil Pump Drive Sleeve not being driven.
Because there is no mechanical drive (apart from friction) to drive the Oil Pump Drive, its important that a bearing with as much face contact with the Drive Sleeve be used at the rear of the Gearbox.
The following picture is of the original bearing.
You will note that there is practically no radius between the face of the inner race and it’s bore, affording maximum contact with the Oil Pump Drive Sleeve.
The original bearing has not been available for a long time and the the following picture shows the bearing that is supplied by most as the replacement.
Note the size of the radius between the face and bore of this bearing. With this bearing, the engagement land between the face of the bearing and the Oil Pump Drive Sleeve is only around 0.5mm (0.020").
The force due to friction is generally independent of the contact area between the two surfaces. Accordingly, friction, per se, to drive the Oil Pump is not the initial issue. However, this small surface area contact can lead to deformation of the contact surface of the Oil Pump Drive Sleeve and the clamping force applied by the Companion Flange Nut reduced. Once this starts to happen, the affect is exponential and drive to the Oil Pump Drive Sleeve diminished.
You can see that even with the original bearing, with full contact with the Oil Pump Drive Sleeve, there is visual evidence of slippage.
Thanks for the info
I am going to have a look tomorrow