Gearbox oil change

[GM6VXB]

Still doing lots of checks, but last night decided to drain the gearbox. Took the drain plug out and ended up with both the plug and a piece of metal (see picture).
This morning jacked the car up higher and found TWO holes into the gearbox. One obviously is for the drain plug, the other I have no idea about, but it could explain why the underside of the car is coated in oil        
The second hole does not have any signs of a thread cut into it
I cannot see how to make the second hole oil proof unless I resort to some drastic measures.
So oil change is on hold while I see if I can come up with a solution.

Anyone know of a 'fix' for this ?.

BTW the car is a 7 Tourer of 1933 vintage.

Martin.

[David Stepney]

It looks as if the unthreaded hole is a drain for any oil that finds its way into the clutch pit.

[Colin Morgan]

...and the 'bit of metal' that came with the plug is there to stop muck from getting into said clutch pit, but isn't supposed to seal.  Also, as can be seen in the picture, oil is more likely to be seeping from the sump nearby - and also from other places higher up on the engine such as the block to crankcase joint.  This is not unusual.

When refilling the gear box, it is  good idea to leave the oil level a bit below that specified by Austin originally - this helps it stay in the box and not end up on the clutch.  (I run my Ruby box at exactly 3/4" below the top gearbox face where the filler hole fits and that seems to work.  Various threads on here refer.)

[GM6VXB]

Thanks both.
Managed to get further under the car (not good when you have Labirinthitus) and yes it goes into the belll housing.
Had me a bit confused at first as feeling in the hole with fingers I thought I could feel a gear, now know it was
the flywheel !!.

Will underfill the gearbox as recommended.
Back axle is next on the list, plus good inspection of UJ and flexible coupler.

Thanks again.

Martin.

[Denis Sweeney]

Martin, there are similar comments on this forum regarding oil levels in the rear differential and problems of over filling and finding that the excess oil eventually makes its way passed the oil seals and out through the break drums.
Search oil levels and you will find various comments on levels in the engine, gearbox and differential giving advice.
Cheers Denis S

[Reckless Rat]

The gearbox uses engine oil as a lubricant, so either straight SAE30 or 20W-50. fill to the bottom of the threads on the level plug, no more.

For the rear axle, jack up the car under the rear cross-member, which allows the axle to hang down under its own weight. That's when you should check the level. A 33 'D' type axle should take 250ml of SAE 140 oil. You need a syringe to get it in. Fill until it runs out & then let it drain before putting the plug back in. Standing the oil in hot water beforehand will help to thin it a bit.

[GM6VXB]

Reckless Rat, rear diff drained, but will leave it overnight and start re-filling tomorrow.
Going to use an old oil can with a flexible spout and tip cut off to re-fill.
Managed (just !) to get my Boroscope inside the diff. Crown and pinion look in fairly good condition.

Being a new (to me) car, I am on a fairly steep learning curve but want to give it as good a check as I can
before taking it out onto the roads.

Found quite a bit that is not quite right, but fairly easy to sort. Main (and probably the most expensive) problem
is a dead dynamo which I am hoping to send off next week for inspection and repair. Not sure how long it will take
but hopefully about a month.

All electrics now working including conversion to LED. Interior stripped out, floor painted and carpets re-fitted.
Still trying to figure out the side screens but they do fit all but badly.

Still quite  lot to do, but getting there slowly.

Martin

[Reckless Rat]

Best left overnight. Diff oil is quite thick and treacly so takes a while to fully drain out. Same after you've filled - let the excess drain back out. Too much oil just causes problems at the hubs with it getting past the seals & onto the brakes.

If you can see into the level hole, rotate the axle so that you can inject the oil past the crown wheel. It saves a bit of mopping up...

On the subject of your gearbox, if the car is a 1933 model it should be fitted with a four speed crash box. This is easily identified by the presence of a large forward facing nut on the gearbox top casting, ahead of the gear lever. Later cars, (without the nut on the casing) will have a synchro box, either on 3rd and 4th or 2nd, 3rd & 4th.

However, the 4 speed crash box is very cleverly made, robust and pretty reliable, if a bit slow to operate by the double de-clutch method. Forget 1st gear - most of the time you can just set off in 2nd. It only featured in 1933 model cars.

[andrew34ruby]

Martin, although I've owned my 1934 seven for 40 years, I've only had it on the road for the past 3 years so I am really a beginner. Working from advice on here I find it best to not study the gearbox and axle oil levels, but rather to drain it all out and replace with a measured amount of oil.

As for the dynamo, it's quite easy to take it all to pieces and see what is wrong. And with a non-working dynamo fitted, daylight running need not be limited if you charge the battery when you get home.

[AustinWood]

Fille the axle with it hanging loose on its springs with no wheels. Sipport the chassis on stands.