Aus 5spd/split case rebuild+upgrades (1 Viewer)

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Joined
Nov 21, 2019
Threads
12
Messages
166
Location
San Jose
Last spring I bought a 2H drivetrain from and Australian HJ60 with the intention of swapping it all over to my 40 series. I am just now getting around to tearing it all apart and decided I would make a thread on the rebuild process.
The plan for the t-case is to convert to manual shift and put in a 3:1 gear set. I am hoping the trans will only need seals and bearings as I dont know much of the history on it. Heres a few pics of what I was starting with.

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First thing I did was pull off the bell housing and scrub it down clean enough to put into the media blaster. it came out looking like new. I found a strange hole drilled into the case for something it doesnt look factory so I will make a plug and weld it up at some point.

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I pulled the top plate off to see how the gear set looks, I didn't get a chance to measure any clearances just a basic visual. Unfortunatly it looks like a tooth in the input shaft gear has some pitting or scoring. I am not sure if anyone here is see worse and run it with no issues but I feel like if rebuilding then a new input shaft/gear might be necessary?
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When I got the cases open I was slightly worried with what I found.
1) the idle shaft thrust bearing looked like it might have spun in the housing. There is a very small groove, looks alot worse than it is, I can barely catch a finger nail on it.

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2) Hi/Lo and idle gear wear.
the faces of all of these teeth seem like they are in good shape. I will go through the FSM and the process involved to check clearances which will determine if the gears are good. Before I get that far can someone advise if the burrs around the edges of the teeth are an easy indication if the gears are toast?

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A few more of the case opened up:
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Looks like a fun project, what's the mileage on the drivetrain?
 
Looks like a fun project, what's the mileage on the drivetrain?
Thanks yeah so far its been fun, I've only done 1 other transferase before this one so still learning a lot.
Unknown mileage probably 150k+? but no idea. it looks like it has been opened up least least once before.
 
Very cool. I would say those burrs on the tcase gears are metal displacement from a lot of miles and wear. Perhaps got too hot running with not enough oil which softened the metal some degree? If the actual tooth clearances are good I would still take a Dremel and deburr the teeth if time allows. Might not NEED to; maybe it's just my OCD, but I wouldn't leave them like that if you reuse them.

You going to rebuild the H55F? My 3rd gear syncro is loose it turns out (cone portion isn't gripping the gear to synchronize so I hit a solid stop initially when shifting into 3rd). Sure wish there were upgraded syncros for the H55F like there are for a lot of domestic manuals.
 
@Spook50 yeah the plan as of right now is to rebuild the H55F, im not sure how healthy my synchros are since I never drove it? I think im going to put in a compete fresh set to be safe. For the split case I think im going to do the 3:1 gear set so I believe all of the suspect gears with burrs wont be getting reused. Also going to be doing twin stick for simplicity and getting away from the vacuum operated system.
 
took a break to work on some other projects but now back on this. I pulled the gear set off the trans output shaft. The splines where the gear rides is showing some of the characteristic wear on the root and face of the drive side of the splines. it doesn't seem too bad but I'm not sure what is too much? Gear teeth all look good.
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I sent out all the hardware and a few other random parts from the trans and case for plating. I got everything back and had to do a quick mock up to see how everything looked.

I still need to clean and blast the other case half, machine the cases out to 38mm and buy rebuild kits and gear sets
Plenty of work to go but the little bit of progress looks good.

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I sent out all the hardware and a few other random parts from the trans and case for plating. I got everything back and had to do a quick mock up to see how everything looked.

I still need to clean and blast the other case half, machine the cases out to 38mm and buy rebuild kits and gear sets
Plenty of work to go but the little bit of progress looks good.

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That looks REAL purty! Wish there was a place near me that did yellow zinc plating. I researched doing it at home, and nooooooo thanks. Hard pass on that one. I'll leave it to a professional shop. Can't beat the look of a clean case and freshly plated hardware though.
 
Well thanks for that.
Now I feel like I should wear a bag on my head for not cleaning up my transfer case better during my swap.
Looks great!
 
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