Transfer box enquiry

[AndycruiserguyLomas]

A friend of mine with a 300K really quite smart Collie is looking for a manual gearboxed transfer box in good condition.
His is rattily but not jumping the chain (yet).
I thought I'd read that the TB is different on manual and auto's and wondered if they were interchangeable with modification or it was a no.

Help is needed so if anyone can advise it would be appreciated.

 

[BobMurphy]

The TBs are basically the same on autos & manuals. The differences are:

1. On an auto, the two selector shafts stick out the front. The transfer lever is mounted on an extension piece at the rear of the auto gearbox.
On a manual, the shafts are internal with the transfer lever mounted on a turret on the TB.
There is a blanking plate on the turret hole on an auto TB.

2. A manual TB has synchtomesh on the high/low ratio selector dog. On an auto the synchro cones & springs are missing.
(The Auto cpu requires the car to be in neutral and stationary before selecting Low - a manual can be selected on the move, but slowly).

3. The auto TB has two switches detecting Low Ratio. One for the dash light and one for the auto CPU. The CPU alters the gearshift characteristics in Low.
A manual TB has one Low detector switch.
Each has a single detector switch for Centre Difflock.

4. The casings and remainder of the internals are identical between the two and can be mixed and matched.

Hope this helps.

Bob.

 

[AndycruiserguyLomas]

So, Bob, having a manual and an auto TB next to each other off the truck, the parts can be interchanged and a good working TB can be installed or is it a strip down job?

many thanks for your reply.

 

[BobMurphy]

So you want to build a manual box from an auto. . .

It's a strip-down job as the two selector shafts are shorter in a manual and they would have to be swapped from the old manual box.

You would miss synchro in a manual So that would have to be swapped over.

Remove the additional Low detector switch and replace it with the screw-in plug , swap the TB lever turret for the blanking plate.

That's it (I have done this myself).

Building the box has to be done with care, this isn't a 'beside the road' fix !!

Bob.

 

[BobMurphy]

When I get back on my main computer I'll post some pictures.

Bob.

 

[BobMurphy]

The differences between a manual and an auto Transfer Box - in pictures.

An Auto TB has the selector shafts protruding from the front, three detector switches and a blanking plate where the Transfer Lever Turret would go on a manual box.

A manual TB has the selector shafts internally, a Transfer Lever turret and two selector switches:

The correct selector shafts have to be assembled with the main gear cluster:

Before being inserted into the main case as a set:

I haven't shown the assembly of the Synchromesh cones and springs, but could if anyone wants to see them.


Bob.