How do I fill the diff? No joke.

[wild_willy]

Pretty basic question right? Never had this issue before.

In the process of rebuilding a late Aug 1937 diff but have discovered that there is no provision for a filler plug. The RH diff housing has no plug for a filler in fact no boss provided in the standard position. It would seem that the LH housing may be not original to the diff but it is a semi Girling housing.

Does the later Girling diffs have a filler in the LH housing? Can someone please tell me the type of thread and plug and where is it positioned? A photo for positioning would be most useful if someone has access to a similar diff.

I removed this diff from a car I was restoring about 10 years ago and I'm guessing that it never had an oil change since a rebuild somewhere in the 60's as you would need to take the diff out of the car, invert and fill through the drain plug.

Thanks to those who may respond to my dilemma.

Bruce from downunder.

[stuartu]

A clue may be found in the A7CA archive digitised parts lists. The one for the 1938 full Girling rear axle (which had a centre which is D shaped) has a filler hole in the side plate. I presume the filler plug doubled as a level plug. You can just see it in the illustration. Publication 1586a.

Many years ago I became tired of the contortions required to fill the rear axle of my type 65. Removing the level plug was easy enough but inserting the oil was awkward - I lacked the 90 degree fitting which would have made it easier. I added a filler plug to the side plate; jacking the car up and removing a rear wheel seemed a lot easier than the previous nonsense and access was excellent.

I wonder if your axle was an "early adopter" of the full Girling filler?

Regards,

Stuart

[Parazine]

Maybe a mixture of parts has married a side filler "D" half (no rear filler point) with an earlier side plate (also with no filler), resulting in an axle case with no access to fill with oil....

[bob46320]

Is there an air vent tube, it would be small if it exists, but a possibility to squirt a measured amount of hot oil in there ?

[Colin Morgan]

So, there is an axle somewhere with two fillers?

Drill and tap in the right place? (Off the car)

[squeak]

according to the austin service journal february 38 they changed the filler plug to the nearside thus the offside had no hole. You therefore have an early nearside housing and a late offside one. I have the measurements for hole placement and can post them to an address

[wild_willy]

Thanks for all the informative responses. Now I know that I'm not going mad looking for the invisible filler.
Can't quite understand why Austin changed the filler position so late in production though. Looks like I have a mismatched pair of diff housings leaving me without a filler plug.
I will drill and tap a new filler hole in the nearside housing.

Thanks Squeak for your kind offer to send me the filler position information. I have sent a PM with my address.

Thanks again
Bruce

[Nick Salmon]

I put new wheels and tyres on a trailer the other day. Some time later I went to check tyre pressures. Did one side, then went to do the other. No valve! No valve hole! Took me longer than it should have done to realise the wheel was on back to front...

[Colin Morgan]

The brake rod for the July '38 onwards rear brakes passes close to the axle casing on the driver's side, on its way to the swivelling 'tree' mounted on the casing which activates the rods that go to each side. I think that is why the filler was moved.

[Cliff Ringrose]

I suspect that the reason the design was changed so late in the production run is that in 1938 Austin did not know that it was late in the production run. Production was stopped by a certain little unpleasantness a year later!