Usual procedure with tiller worm drive gearboxes, is to fill until the oil level is at the bottom of the filler plug hole. Unless it has a second level plug fitted, which should be obvious if it's there.
No idea on the quantity required, but you'll probably have to buy at least a litre anyway.
Usual oil type is a gear oil in the SAE90 to 140 range. But as the pinion is 'yellow metal' [i.e. bronze or brass] in these, from a past ODK thread, the oil must NOT contain sulphur-based Extreme Pressure [EP] additives. These are corrosive to copper alloys.
So common automotive driveline oils are not suitable.
Penrite's 'Transoil 90' or 'Transoil 140' would be about the easiest to get, in a smallish pack size [1L]. These oils are formulated for vintage car drivelines, made before the advent of the 'hypoid' design of diff gearset. Edit: There is some evidence that these tillers were made by MTD, though I can't readily locate an exact user manual. Nonetheless, all of the 1980's MTD worm drive models I've found used SAE140 oil, API GL-1 Spec. Which those Penrite Transoils meet.
These tillers were a Victa rebadge, probably of US origin. It would be necessary to work out what the manufacturer and their model designation was, to find more detailed info, as there doesn't seem to be much about under the Victa name.
Last edited by Gadge; 16/05/1505:41 AM. Reason: add oil spec
Cheers, Gadge
"ODK Mods can explain it to you, but they can't understand it for you..."
"Crazy can be medicated, ignorance can be educated - but there is no cure for stupid..."
Righto, then. While the chassis details differ, and therefore the parts list is of limited use, I think this is as far as we need to look, for correct servicing info.
For the gearbox, the plug visible at the front is the level plug, and that at the top is the fill plug/breather. There should also be a drain plug on the underside, somewhere to the rear of the tyne shaft. This would require that the machine be tilted rearwards, and left propped up, to drain the oil.
5 fl oz is about 150mL, near enough, and that's the amount of oil to use, after draining the gearbox.
Ta muchly for the pics, Karl. This is most valuable, in building up the ODK 'knowledge base' for these machines.
Cheers, Gadge
"ODK Mods can explain it to you, but they can't understand it for you..."
"Crazy can be medicated, ignorance can be educated - but there is no cure for stupid..."
Old post but if this can help. Appears pretty identical to my Victa rotary tiller. Gear case tiller Series 9 Model 355. It has a B&S 5hp 130202 Type 0523 Code 0179050906. Gear case assembly TM64073A. I have tried Google on TM part numbers, but with no success. Gearbox oil - manual says 6.5 ounces Pennant oil EP 35000. I have been using gear oil sae 90 and some pumps of grease. (Thanks for the note about oil additives and bronze bushes!). I guess if the worm drive packs then that is it. However, without having taken them out yet, I would imagine that the bearing and seals could be located locally. The castellated screw on the front is a bearing adjustment cap, but I have been unable to find any description of adjustment. Make sure thread is clean and can be turned in by hand until very slight pressure is felt, then back off until next hole will fit the cotter pin - at least that is how I have done it. Hope this may help someone. Americans seem to love their old machines and there are some really useful web sites.
main problem with these tillers were gear box oil leaks gearbox seals don't like dirt If you only use it two three times a year to churn the vegi patch just top the oil level up every time you go to use it they take bugger all oil