Agreed on the Roadsmith, was only trying to provide the visual of the different design and it helped me understand what Matches has been talking about as regards the Roadsmith (on a side note, the Roadsmith set-up looks pretty impressive)
You've made some very good points, "steamer", and I'm following what you're saying. I also tend to agree with your logic, but at the same time, am trying to keep in mind what Clay@Lehman and my auto mechanic bud have been saying and I still want to bounce some questions off my bud in light of what you've said. Essentially, I'm not certain, but am not going to drain the differential just yet unless or until it seems like a must-do item.
Your Motortrike is the 7.5, this Lehman is the 6.75, both with solid axles, both installed upside down (and thanx for providing that info as well). Also in agreement with what you've said about the Motortrike diagram making it appear as tho' the installation is right side up, but remembering their notation that says something to the effect of "diagram is for parts location reference 'only'", which could mean that the diagram doesn't mean that it's actually installed in the position that the pics show.
When I first asked my bud about the fluid capacity, he said to not be concerned about any capacity spec, just fill it to the level plug and that's the capacity. When I mentioned the 30 oz. figure to him, he said that 30 oz. would barely lube the ring and pinion gears and probably wouldn't be sufficient to reach the end bearings as you've also said. When I told him that the rear end was installed upside down, THEN he agreed that the 30oz. spec might be O.K. Please keep in mind, this is all for the sake of conversation and not argument, and again, I want to pick his brain a bit more on this. He came over here, took one look under the Lehman and immediately said "Yep. That's an old 6 3/4" Ford rear end". He crawled underneath briefly to inspect the relocated vent and to see where the level plug was situated. The way he left it that day was advising me to remove the housing cover to drain it, then to add the 30 oz., then to make a dipstick out of welding rod with the known 30 oz. in there because a dipstick would be the only way to check the fluid level since it would be well below the level plug. As far as any overfill condition, his thought was that it would not blow out the rear end, but the excess could find it's way into the brake drums and foul things up in there. Again, I'll chat with him again to double check before deciding to put another wrench on this Lehman just yet.
