Transfer output gear bushing install

[Eurasiaoverland]

I have just replaced the bronze bushing in the low-range transfer output gear, using Toyota p/n 90999-73089. This bushing is shown in factory diagrams for the early (pre ~1985 I think) split case transfers, but not in later examples. Mine is a 1989 from behind a 3B / H55F.

I have pressed the bushing in so that it is flush with the edge of the chamfer on the side of the gear with the shift sleeve teeth:

On the other side of the gear, the side with the thrust face that rides against the rear output shaft front bearing, the bushing appears to be oversized. I have knocked it in a touch to be sure that it will not ride on the bearing, but it come up past the cut-away sections in the thrust face lip:

Now, the question - are these cutaway sections there to facilitate bearing removal, or are they to allow oil to flow through the bushing? If it's oil flow, Should I carefully grind away (with a carbide burr, not abrasives) the obstructing part of the bushing?

For those who are interested, this bushing needs to be reamed (not honed) to size after installation - that's the next job when an adjustable reamer turns up.

Thanks

EO

 

[LazarusTaxa]

Yeah, I made the mistake.. I have an '87 FJ60 and it's one of the few areas where the parts diagrams were wrong. I ordered 90999-73089 and also found them to be too long. I don't specifically remember if they covered those two notches. But, I believe those notches need to be left open to allow oil to flow down to the shaft and bearings on either side.

I called Georg at Valley Hybrids and he immediately knew the issue and got me the right bushings which are narrower and fit properly. That PN is 90999-73079 which confusingly is listed as fitting LCs from 1976-1980.

I'm not 100% sure you're in the same situation, but it sounds like it and this was my fix...

 

[Eurasiaoverland]

Yeah, I made the mistake.. I have an '87 FJ60 and it's one of the few areas where the parts diagrams were wrong. I ordered 90999-73089 and also found them to be too long. I don't specifically remember if they covered those two notches. But, I believe those notches need to be left open to allow oil to flow down to the shaft and bearings on either side.

I called Georg at Valley Hybrids and he immediately knew the issue and got me the right bushings which are narrower and fit properly. That PN is 90999-73079 which confusingly is listed as fitting LCs from 1976-1980.

I'm not 100% sure you're in the same situation, but it sounds like it and this was my fix...

Thank you very much - that is exactly the situation I am in, it seems. To be fair, the part diagrams for my '89 don't show separate bushings at all, so I ordered at my own risk.

Out of interest, did you have to size -73079 with a reamer after installing?

From what I can see online, -73079 is still different from the bushing which came supplied with my new, genuine high range output gear:

Right now, I'm thinking to carefully remove parts of the bushing that are obstructing the cut-outs in the gear, ream it and run it.

When I intstalled the bushing, I aligned the oil hole with a groove in the gear, but I now notice that the ends of the oil grooves on the bearing side do not match with the cutouts. But then they don't match on the new gear / bushing assebly pictured above.

End of the day, the bushing is not oil fed but sits in a (partial) oil bath - it also does not move when under load (i.e. when the transfer is in low-range), so I doubt oiling is all that critical. Having thought a bit more about it, I think the cutaways are actually to bring oil onto the machined thrust faces of the gear, rather than into the bushing.

Happy to be corrected by an engineer though!

Thanks again,

EO

 

[LazarusTaxa]

How would you carefully remove any of that bushing? I thought it might be possible to put it in a lathe and turn it down to the right length, but new correct bushings are not that expensive, so easier.

I had a machine shop press mine in and hone them to fit as they were already doing some other work for me.. I'm not sure that he paid any attention to orientation, so we'll see how long the last.

 

[Eurasiaoverland]

How would you carefully remove any of that bushing? I thought it might be possible to put it in a lathe and turn it down to the right length, but new correct bushings are not that expensive, so easier.

I had a machine shop press mine in and hone them to fit as they were already doing some other work for me.. I'm not sure that he paid any attention to orientation, so we'll see how long the last.

I don't think orientation is an issue - I have been looking at online pictures of new low-range transfer gears 36204-60080 and the replacement -60110, both genuine and aftermarket options and they don't seem to have a uniform orientation of installation. I matched my oil hole with the groove in the gear, so I'm happy. As I said, I don't think oiling is so critical here like on a camshaft or piston pin, otherwise there would be oil feed holes as there are for the bushed 3rd gear in an H55F/H4x transmission.

I plan to take some of the material off the busing very carefully with a die grinder, clean the edge with a file and perhaps put a slight chamfer on the rest of the bushing before reaming the thing out to a snug fit on the output shaft. I would not trust machine shops where I live to do anything more than brake disc skimming so prefer to do it myself. The way I see it, I have more contact area between bearing and shaft, more resistance to the gear rocking on the shaft and hopefully a larger oil film.

This gear will spend 99.9% of its working life idling on the shaft, where the gear will be turning with the propeller shaft's rotation of movement, while the shaft in the bushing will be turning in the same direction but faster. I really can't see oil flow being a problem.

Interestingly, my old low-range gear bushing was totally black and looked almost corroded away to the point where it is hard to see the grooves any longer. It came out with the shaft when I knocked it out of the gear/bearing.

If only Toyota had used needle roller bearings on the shaft, as they did for 60s with auto boxes!

Thanks

EO

 

[Spook50]

I don't think orientation is an issue - I have been looking at online pictures of new low-range transfer gears 36204-60080 and the replacement -60110, both genuine and aftermarket options and they don't seem to have a uniform orientation of installation. I matched my oil hole with the groove in the gear, so I'm happy. As I said, I don't think oiling is so critical here like on a camshaft or piston pin, otherwise there would be oil feed holes as there are for the bushed 3rd gear in an H55F/H4x transmission.

I plan to take some of the material off the busing very carefully with a die grinder, clean the edge with a file and perhaps put a slight chamfer on the rest of the bushing before reaming the thing out to a snug fit on the output shaft. I would not trust machine shops where I live to do anything more than brake disc skimming so prefer to do it myself. The way I see it, I have more contact area between bearing and shaft, more resistance to the gear rocking on the shaft and hopefully a larger oil film.

This gear will spend 99.9% of its working life idling on the shaft, where the gear will be turning with the propeller shaft's rotation of movement, while the shaft in the bushing will be turning in the same direction but faster. I really can't see oil flow being a problem.

Interestingly, my old low-range gear bushing was totally black and looked almost corroded away to the point where it is hard to see the grooves any longer. It came out with the shaft when I knocked it out of the gear/bearing.

If only Toyota had used needle roller bearings on the shaft, as they did for 60s with auto boxes!

Thanks

EO

Doing a butt load of research given the consideration that the bushings could possibly be an issue with my case and stumbled across your thread; what prevents use of the needle bearings in a late 60 case? Outer diameter of the shaft or inner diameter of the gear, or something else entirely?

If it's a diameter issue, I'm wondering if the couple of machinists I know could help me out with making a needle bearing work.....

 

[Eurasiaoverland]

Needle roller bearings were used on the split case transfer behind auto boxes. They run different transfer output shafts (and maybe gears, I forget). And the bearings are no longer available from Toyota. So it seemed like a big hassle to try to get questionable used parts for something that might not work.

In the end, I tried an adjustable reamer on that bushing in my photo. What a tool. Made a big mess of things, so I pressed it back out.

Then installed -73079 and had it sized at a machine shop on a lathe.

 

[Spook50]

Needle roller bearings were used on the split case transfer behind auto boxes. They run different transfer output shafts (and maybe gears, I forget). And the bearings are no longer available from Toyota. So it seemed like a big hassle to try to get questionable used parts for something that might not work.

In the end, I tried an adjustable reamer on that bushing in my photo. What a tool. Made a big mess of things, so I pressed it back out.

Then installed -73079 and had it sized at a machine shop on a lathe.

Yup definitely gonna have to stick with a bushing then! When you had them machined did you have it done to the exact diameter of the shaft or did you have them allow a couple thousandths of a millimeter to give clearance for oil?

Strange that the needle bearings are NLA and the bushings are not.

 

[cruisermatt]

The needle bearings are only found in 88-90
transfer cases behind autos, after that they went back to bushings. The high and low gears that go with them have a larger bore to accommodate. The bearings and gears are definitely available new, however personally I would rather have the bushing, if you think about it when the gear is engaged you have 360-degree contact with the output shaft vs just the small surface area of the bearings. The bearing isn’t spinning if the gear is engaged.
Toyota must think so too, since all new splitcases (they are still being used on new HZJ79’s) all have bushings.

 

[Spook50]

The needle bearings are only found in 88-90
transfer cases behind autos, after that they went back to bushings. The high and low gears that go with them have a larger bore to accommodate. The bearings and gears are definitely available new, however personally I would rather have the bushing, if you think about it when the gear is engaged you have 360-degree contact with the output shaft vs just the small surface area of the bearings. The bearing isn’t spinning if the gear is engaged.
Toyota must think so too, since all new splitcases (they are still being used on new HZJ79’s) all have bushings.

Now that actually makes a ton of sense.

 

[Eurasiaoverland]

The needle bearings are only found in 88-90
transfer cases behind autos, after that they went back to bushings. The high and low gears that go with them have a larger bore to accommodate. The bearings and gears are definitely available new, however personally I would rather have the bushing, if you think about it when the gear is engaged you have 360-degree contact with the output shaft vs just the small surface area of the bearings. The bearing isn’t spinning if the gear is engaged.
Toyota must think so too, since all new splitcases (they are still being used on new HZJ79’s) all have bushings.

You're right about the bearings, not sure where I got that idea from. Thanks for making the correction.

But what you say about them being discontinued after 1990 is not the case; they kept using them on autos, e.g. JDM HZJ76s until 2004. Just not in the US.

I agree with your thinking on the bushing, though you could make the same argument for all the gears (except the reverse idler) in the transmission, and they all use needle rollers. But maybe long-term, for those owners that never take the transfer out of high range, the needle bearings could notch the shaft... though this is purely an idea. I think the fact that they only used the needle roller bearings on autos suggests that the greater shock loading from a manual transmission is better accommodated by the bushings.

Do you see different wear patterns on autos vs. manuals?

When I got my bushing machined I asked for the FSM specified oil clearance, but it still felt tight on the shaft. The machining was done on the low range gear. I had a brand new shaft and high range gear, so I got them to open the bushing up a tiny bit more, until it felt the same drag as the factory machined bushing.