Non-standard Leaf motor/trans orientation?

[zl3ag]

Greetings,

One of my tractor conversions sees me wanting to mount a Leaf EM61 motor and trans 90 degrees rotated so that the motor is at the bottom and the diff is above it.

Anyone see any negatives to this?

The only one I can think of is possible trans oil leakage out of the parking detent motor thingie.

The trans oil fill/drain plugs will all be way above the actual oil so doing a drain and fill would require a pump, but considering the mileage this conversion will end up doing, that's not a show-stopper.

Anyone trried this before?

[Zieg]

You'll also need a pump running constantly to circulate oil up to the diff bearings, gear teeth (and intermediate shaft bearings if the box is from a pre-2020ish model with open bearings). You may also have to plug the vent hole that exits between the reducer and the motor face, though with the way the baffling works that's usually more of a problem when the box is mounted with the motor at the top.

[zl3ag]

Ah. Is replacing those open bearings with sealed one a possible fix rather than the pump?

[Zieg]

No, because it doesn't address the matter of getting oil to the gear teeth, nor the tapered roller bearings on the differential output. I also haven't managed to find sealed bearings that have sufficient speed rating, not sure how Nissan did it.

[zl3ag]

Well, that's certainly a bummer!

[jrbe]

Sealed bearings can be problematic because of grease and transmission oil mismatches. Certain (most? All?) greases that mix with oils can ruin the grease and then ruin the bearing. Pressure difference over time can have the oil or grease migrate & mix. It's been a problem with a few different vehicles where the OEM thought this was a good idea and things went very sideways.

You might be able to bend up some steel lines to feed oil where needed inside or outside the transmission.

[zl3ag]

Hmmm.

I'm trying to make this a very easy conversion so that people with low engineering skills can copy it. Having to arrange oil pump/feed piping puts it higher up the skill set.

Given that this tractor will have a 30km/h speed limit when driven on the road, and is very unlikely to exceed that on the farm, (so gearbox RPM won't be excessive) maybe I just over-fill it with trans fluid to the extent that I'm sure the topmost bearings are getting splash fed?

Maybe glue some wee plastic scoops on the side of the diff ring gear to ensure there's a lot of splashing?

[jrbe]

The loads will be very high on the bearings and gears if this will be used like a tractor. So the lubrication may never make it to the upper gears and bearings when doing slow & heavy work and very likely won't be splashing in an effective manner most of the time.

My suggestion would also be an electric pump that runs while in forward or reverse that feeds bearings and gears if you need to go this route.

Alternatively using just the leaf motor with an adapter plate and shaft coupling to the stock tractor transmission could be a good solution. 2 complex parts to eliminate a bunch of medium complexity parts, systems, potential leak points, etc.

[jrbe]

Also, considering the slow RPM use, you might be able to fill the oil up to the bottom of the driveshaft seals in the diff in it's new orientation. Might have to add seals and plug up a few things in the case where oil would leak. Might be a simpler route.

[zl3ag]

Yeah, I might as well try that.

If it fails, it fails and I move to the motor-only option. :^)