What does this part do in a UN1?

[Ray]

I am currently rebuilding my UN1 along with several modifications to my car. I have been kicking around ideas about running either a shaft driven water pump for my intercoolers or shaft driven oil pump for the box. This mysterious little part ( see area in red circle ) is in the area I would like to run my shaft connection. I am guessing this is some how related to oil flow but cant get my head around how it works. If I am adding an oil pump to pump oil and returned over the ring gear and 5th gear overhang...is this part still needed?

Any answer to what this part does and how critical it is would be appreciated.

 

[Stephane Goria]

Hello,

This part flows oil in the primeshaft. The primeshaft is drilled at its bottom side to allow this inlet to fit inside.

The way it works is simple. Oil flow along the walls of the cover and part of this oil is redirected into the primeshaft through a kind of pocket that handles this inlet.

You must absolutely keep it.

Having a mechanically driven oil pump is a good idea, and you can use the secondary shaft to do this. I would recommend you to have a look at UN7 drawings (4 wheels drive UN1) to study this option. Because of the 4 wheel drive they attached an extension to the secondary shaft and it may give you ideas on ways to use the secondary shaft for an other use.

Cheers

Stephane

 

[Danny]

Stephane, not all end covers have that oiling device. Have you or anybody else come up with a modification to add it?

 

[Stephane Goria]

Hello,

You are right.

In fact all UN1 after 1986 have the oiling device. It is a revision done to the gearbox.

The parts impacted by this revision are the end cover and the primeshaft.

The focus was to bring more oil to the steel bush of the 5th gear system. Bush bearing (I dont know the exact word in english ie I mean bearings with no needles or balls inside, just steel to steel contact) works ok if there can be an oil film between the 2 parts in contact. The position of thsi bearing on the primeshaft, wich means outside of oil bath, was a weak point for these gearboxes.

So basically if your end cover is casted 86 and up, you should have the oiling duct.

Cheers

Stephane