AA Tapered Bearing Conversion

So, after wearing out the intermediate shaft on my new TeraLow t-case in less than 1000 miles, I decided to do the AA tapered bearing conversion. Here's the old shaft:



It's in the mail back to the supplier for hardness testing.

I sent the intermediate gearset back to Mcruff to have him machine it to receive the bearing cups for the tapered roller bearings. Here is a short video he sent me showing what goes on when you cut something that is Rockwell 55 on the hardness scale. looks pretty cool.



I haven't received the gearset back yet. Probably show up on Wed or Thurs.

I also sent him the planetary hub from my Saturn OD to see if he could machine a different location for the tab on the special washer that keeps the unit from coming loose from the tranny output shaft. He could, and he did. Here's a pic of it.



The two shiny spots are the new recesses. The originals were all located under the planetary gears and made it very difficult to get the washer in or out. I'll post up more pics as I put this all together.

 

Yeah I was definitely considering the same thing.
Did you run the O.D. unit with the Tera low gear set ?
Does the 3.15 gear set run a lot louder than the 2.46 gear set ?

 

Wow, that shaft is wrecked. I guess thats what your noise was.

 

I haven't run the OD with the Teralow yet. I just bought the bowl gear to match the Tera gearset. It'll be going in as soon as I can get the planetary hub back together. It should be a challenge. The four planetary gears have double sets of loose rollers, like the intermediate gears in the t-case. The pins that go into them are a press fit and are pretty tight in the hub.

As far as noise, I didn't hear any real gear noise from it. It turned out the noise I was getting was from the large intermediate gear contacting the 4wd shift rail. It is a known issue with this case, but the builder (not me) either didn't check it or just missed it when it was built. The contact was light but enough to make a buzzing kind of sound. Then when the intermediate shaft got really bad it allowed more contact with the shift rail. It was dead silent in 4wd as then the shift rail was moved away from contact with the gear. I don't think there is any more gear noise from these gears than a stock 2.46 geared unit. The nice thing about the OD is when you are in overdrive you basically are back to around 2.46 in the t-case. I really like the 3.15, but I found myself running a lot in 3rd and 4th gear on the trail when in Low range. With the Teralow, a Ford t18 and 5.38 r&p I'm just over 100 to 1 in first gear. Very nice for the technical stuff.

47v6: When those shafts get worn like this one, it makes a sound like something rubbing in low range. Put it in high range and they are quiet, until they get really bad. That's how you know when the shaft needs to be replaced. The one that is in the picture was supposed to be hardened to Rockwell 55, and possibly it was, but not to a sufficient depth to make it a serviceable part in my opinion. That's less than 1000 miles on it, and probably more like 600 to 800 as my Jeep is mostly trail use.

 

Mcruff did my intermediate gear also, did a really nice job as always.
Regarding those planetary gears-buy a piece of dowel rod the same diameter as the little shafts they run on.
Cut a piece the same length as the gear and use that to hold the roller bearings in place (along with some trans assembly grease!)

 

That shaft looks like it's just getting broke in! Haha..

 

The Teralow's do work well with the overdrive and definitely give you a lot more options on the trail. I still can't see why Teraflex doesn't just offer the gear set using the AA tapered bearing shaft. Another $100 is sort of non-consequential for anyone willing to spend the money on the gears to start with. As John stated above, I can't really tell much difference in the actual gear noise from the Spicer versions.

 

This was actually the second gearset that Mcruff has done for me. I have another t-case, stock 2.46 low, with the bearing conversion, as a backup.

I had to modify the Novak adapter to the T18 tranny as it interfered with the nut and adjustment collar for the bearing conversion. I'll post up some more pics as I go.

colojeepguy: That's what I had in mind as far as re-installing the planetary gears. I am going to try to push those pins back in with my 12 ton press. Just not sure yet how I'm actually going to set it all up. The pins are still captive in the hub assembly and I may try to install all four gears and pins at the same time.

 

I'd like to see that.
I'm likely going about the same direction except for using the Jeep T18 adapter.

 

I'll try to get a pic up Wed. It required some redneck engineering of sorts, but I think it will work just fine. I don't know if the stock Jeep adapter is different from the Novak part.

 

John,
That video was something. The tool was turning to fast to tell what it was, maybe a boring bar with a carbide cutter? And it looked like it was running without any cutting lube?
I wonder how many tool inserts he went through to finish that job.

Don

 

John , Don ............Yep, I was wondering the same thing! What kind of tooling was that?

 

criterion adjustable boring bar.

 

The real question is what insert did he use to cut the heat treated steel.

 

That is a 2" Criterion boring head turning 500 rpm with a Kennemetal 1/2" boring bar with a carbide KC730 insert in it, they are 3 sided, I used one $9 insert to do both sides. I take a .020 diameter cut each pass to within .005 of finished depth and finish the floor last.

No lube on the carbide tool. Air only to keep the chips out.

 

Here you go, oldtime. I used a hole-saw in a drill press to cut out the area on the adapter plate to allow room for the adjuster collar and nut. The washer needs to be clearanced also, as you can see. I'll probably smooth out the sharp points of the semi-circle left by the hole saw.

 

Yeah that looks real nice so far fb

 

It isn't pretty, but it should work.

 

A little update. Here's what the intermediate gears look like after installing the bearings and cups.





This is the bearing adjuster sleeve. AA only sends one o-ring for this, but it has three grooves machined into it. Since usually more is better, I went to the hardware store and bought two more o-rings and installed them. Good idea or bad, only time will tell. This case was a real leaker from the time I got it. I trying to do everything I can to make sure it isn't a drooler anymore.



I slightly beveled the edge of the intermediate shaft bore so it wouldn't cut the o-rings when I installed them. That edges is really sharp and there isn't really any way to get the sleeve in without damaging the o-rings unless you smooth that edge out a little.



Here's a view of the front of the case with the adjuster nut installed and the T18 adapter bolted up so I could make sure everything cleared.



Here's the mystery bonus photo. It's going to take a really sharp eye, can you see what's wrong with the assembly?



It took me awhile to figure out.

I ditched the castle nut that AA provided for the adjustment and used a real stop nut. Added a little threadlocker for insurance.