Posthole Digger Gearbox capacity

Bruce T · Nov 24, 2016

Picked up a older Howse PHD. Wondering how much gear oil to fill. There is a fill plug on top, but no level plug on the side. I was thinking about flipping it on its side and filling it half way. The plug isn't vented. Any suggestions? Thanks, Bruce

oosik · Nov 25, 2016

Well - I'll take a stab at this. There is the possibility that the fill plug that you currently have is not the OEM plug. If it were mine - I would drill a small hole in the fill plug. This would ensure that as the oil heats & expands - any excess pressure/oil would blow out the vented plug. Then fill the gear case around 3/4 full.

If you lay the PHD down when stored - stick a wooden farmers match in the drilled fill plug so the oil won't drain out.

Stonehaller · Nov 25, 2016

Try downloading a manual at Post Hole Digger Operator's Manual - Product Manuals - Service & Support

oosik · Nov 25, 2016

The OP Manual, at least for the 45 & 75 models, shows the oil level check plug on the front of the gear box directly below the fill plug. Hard to tell by the one pic if yours has a plug there.

Texasmark · Nov 25, 2016

Bruce T said:
Picked up a older Howse PHD. Wondering how much gear oil to fill. There is a fill plug on top, but no level plug on the side. I was thinking about flipping it on its side and filling it half way. The plug isn't vented. Any suggestions? Thanks, Bruce

Judging from where over flow holes are located on most gearboxes I agree with your idea. While you are at it, you might go to an auto parts store....probably mom and pop that caters to farmers, and get a vented fill plug. Sure helps with old seals not leaking.

Bruce T · Nov 25, 2016

Picked up a vented plug at fleet farm. Filled it between 1/2 and 3/4. Punched a few holes in the back yard. Seems all good. Thanks for the tip on the vent plug!

ovrszd · Nov 25, 2016

Bruce T said:
Picked up a vented plug at fleet farm. Filled it between 1/2 and 3/4. Punched a few holes in the back yard. Seems all good. Thanks for the tip on the vent plug!

Unless you are a commercial fence builder, and even if you are, the chances of you drilling enough holes to heat up the gearbox requiring a vent is extremely small. That's why it doesn't have one.

I'd want the oil level at the bottom of the horizontal shaft so oil is contacting the input shaft bearing.