88 EZGO Differential Oil Change

[Ninjaneer]

Background:
I pulled off the back cover and cleaned all the RTV front the cover and housing. I didn't know the best way so I used a dremel with the little wire wheel. I sprayed a little degreaser in there to get out some of the junk and blew it out to the degreaser to drain. I let it drain for a while and then cleaned the surfaces and applied some RTV. I put the cover back on and tightened it up until some RTV squeezed out. I waited an hour and tightened the bolts (the ones not partially stripped) to 18 ft-lbs. I plan to refill from the large set screw towards the front. I plan to use 80W90 but have heard some use 30.

Question:
How much do you put in? The 85 manual says 2 pints, but that doesn't seem right. I have also seen about 6 oz. Others fill to the bottom of some plug. Does the cap in the picture come out?

[Dave Box]

Yes the rubber plug pops out and you should fill the differential to the lower edge of the plug (about a quart). You should use around 80 weight gear oil and not 30 weight engine oil. The confusion arises as the SAE have different classifications for engine and gear oil (yes I know bizarre it is). This means that when you hold the two charts side by side 30 weight engine oil has the same (ish) viscosity as 80 weight gear oil. However gear oil is formulated to resist the shear effect in a gear box whilst engine oil is not. Of course if you have engine oil hanging around you could use it after all we are talking about a golf cart not a Maserati, but if you do then use a straight weight not a mutigrade as the mutigrade relies on engine heat to thicken up and this is not present in your differential.

Dave

[Ninjaneer]

I was afraid the plug would break. Do you usually just pry it out?

[Dave Box]

If you go to the Ezgo Tech forum and scroll to the last thread you will see a nice write up on this subject. As long as you have a rubber plug it should pry right out, mine did.

Dave