Real time T-case rebuild question RE: Hi range gear bushing replacement

[dkyuss]

OK,
So Im rebuilding my transmission/T-case and the bronze bushing in the transfer case hi gear was worn past spec.
I just finished pressing the old bushing out.

The bushing is split, and with a hole on the opposite side of the split, I can only assume to feed oil in/out of the bushing.

The gear is slotted from end to end in the bore in two places, 180 degrees apart.

QUESTION;
The original bushing was installed with the hole 90 degrees (approx) from the groove in the gear bore. The hole and split are 'blind' and flush in the bore of the gear.

My thought was to install the new bushing so the hole lines up with the groove to assist in feeding oil.

The only drawback I can forsee, is that then the split in the bushing would also line up with the groove 180 degrees apart and potentially under supported?

Otherwise, WHY is the groove in the bore of the gear anyways if not to feed oil to the hole?


Maybe Im overthinking this, but dont want to do it twice and cant find reference in manuals.

Thanks!

 

[Output Shaft]

Your logic makes sense.

But

Toyota machining two grooves into the inner bore of the gear is not consistent with it being an oiling channel... Since the bushing has only one hole.

The hole in the bushing may retain oil when it is installed as it was originally (away from the groove). A small reservoir.

Oil to the bushing is supplied via the outer edges. It's drowning in oil.

Since the gear is spinning at high speed (when you're traveling at high speed) the centrifugal force of the gear might spin oil OUT of that channel if the hole in the bushing was lined up with that channel, it might act as a vacuum, drawing oil out of the bushing at high speed. Not the desired effect.

I would reinstall a new bushing in the exact same orientation as the old one. Toyota rarely made mistakes on Land Cruisers.

 

[dkyuss]

Your logic makes sense.

But

Toyota machining two grooves into the inner bore of the gear is not consistent with it being an oiling channel... Since the bushing has only one hole.

The hole in the bushing may retain oil when it is installed as it was originally (away from the groove). A small reservoir.

Oil to the bushing is supplied via the outer edges. It's drowning in oil.

Since the gear is spinning at high speed (when you're traveling at high speed) the centrifugal force of the gear might spin oil OUT of that channel if the hole in the bushing was lined up with that channel, it might act as a vacuum, drawing oil out of the bushing at high speed. Not the desired effect.

I would reinstall a new bushing in the exact same orientation as the old one. Toyota rarely made mistakes on Land Cruisers.

Thanks for your input. My plan was always to reinstall as was originally factory installed.... but history on this old girl is unknown to me and possible someone has already rebuilt in the past. This is the stem of my questioning. Not questioning Mr. T here, just wanting to make sure this orientation is as it was originally engineered.

I see now that the bushing groove that spirals through the bushing is open on either end, and will 'pump' oil when spinning. As I think more of this, I also am concerned that if installed in line, the split end of the bushing would flex/bend outwards into the groove as it is unsupported. Also not desirable.

I will reinstall as removed, hole orientated 90 from the groove.

So why the groove in the bore? Maybe for manufacture?

Cheers!