Appreciate the response. I think the machining part that is being talked about is the half moon void in the carrier (Half moon in the Truetrac and a rectangular void in the Stock LS). Mine has it so I'm OK. Look like it catches a tab that is on the Exciter Ring.
That ring is witch to get on. Is there any tricks to it...other than putting the carrier in the freezer and ring in boiling water? This is what I intend on trying tomorrow.
CDB

 

If you are talking about the ABS ring....all we did was to remove it with a punch, tapping on it all around, and installing it onto the TruTrac the same way..no freezing or boiling water for either the ABS ring or the ring gear. It was a very easy install overall

 

I just put mine together, went around the block, and the ABS light comes on. Yup, I didn't put the ABS ring on. But the original shims and the backlash all worked out, and it runs great, so I'm a little confused as what to do to get it right if I put the ring onto it. I am guessing I will remove shims from the drivers side and add to the passenger side to make up for the thickness of the ring, right? Any thoughts?

 

Guess I don't understand how you got the right backlash without the ABS ring in there, but yes, you will have to change the shims around from side to side when you get that ABS ring back on.

 

I came across this thread quite by accident. I never saw the first page, so I didn't even know you were discussing 8.8" diffs.
Sorry about that, I should have given some details.
I have an Excursion with a 10.5" Sterling Differential.
I replaced the OEM open diff with a truetrac, but I forgot to move over the ABS ring. I took a look at the old Diff today and found that the ABS ring on this model fits around the outside of the unit and not between the unit and the ring gear. That is why mine was perfectly setup by keeping the original shim thicknesses. I just tapped the ABS ring with a soft rubber mallet and it popped right off. I'll try and put the ABS ring onto the truetrac when I have some time next weekend.

My diff tag calls for 75W-140 synth oil, so I filled it with RP75W-140. I see elsewhere in the forums that the truetrac doesn't like synth oil because it can be "too slippery" and can reduce the lock ratio (grabbiness?) and can cause some noise too. Well, I have not found that to be the case for the Royal Purple, even though it already contains a limited slip additive that we don't need. Its runnig very quiet and smooth. I think I can stick with the RP when I refill it after putting the ABS ring on. At almost $18 per bottle, I'm going to try to save most of the oil when I drain the diff.

 

The ABS ring actually shouldn't affect the backlash at all once it is set. The ring gear still mounts to the same surface on the carrier with or without the ABS ring. However, you will have to remove your ring gear to install the ABS ring. There is a notch that sits in a void between the ring gear and carrier mounting surface.
I could not get the ABS on easliy and did not even attempt the ring gear. So I froze the Carrier and boiled the ring gear and ABS rig... it went on like a glove. A small glove but none the less. Now I just have to get the old races out of my housing where the pinion sets. A lift would be nice

 

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Thanks for confirming the location of the ring. I will try to boil the rings in a big pot on the BBQ, but there is no way I can stuff a heavy diff into my freezer.

I used the ring gear bolts to very slowly and evenly pull down the ring gear onto the carrier. I know you are not supposed to use the bolts to do this, but it really doesn't take that much force to pull down the ring gear if all of the bolts are used to bring the gear down. I made sure that the bolt holes were very clean by also using high pressure air to blast out any loose locktite and I used new blue locktite on the bolts and that let the bolts go in easily, practically by hand.

Now, I just have to ask... .. How did you get the smell of gear oil out of your freezer, your house, and the pot you boiled the rings in?
.

 

Your absolutely correct, I stand corrected, the ABS ring does have it's own perch, so no shim correction for it needed. I will say though, we didn't need any heat or cold to do the install of the ABS or the ring gear.

Also it would be a good idea to NOT use the synthetic fluid of any kind !!!. I talked to the EATON/DETROIT people on the phone and they were quite emphatic about that point, I feel the pain though, I threw away 5 qts of AMSOIL Synth gear lube and put in Lucas 85-140 mineral...it does run much quieter with that.

 

It was a new carrier which had not been exposed to the stinky gear oil. I did, however, put it in a plastic grocery bag though. For the ring, I cleaned it very well before boiling in a large dish pan...Never notice the first hint of a stink. Actually, my gear oil did not smell no where near as bad as some I have smelled in the past. May be becasue it is synthetic.

So I have a question. What gear oil is recommended by Eaton? or what is best? I bought the 80w90 that was mentioned above and noticed that oil in another thread somewhere. Then above, 85w140 was mentioned.

CDB

 

EATON recommends ONLY mineral type grease with the trutrac 80W90 is fine, I chose the 85W-140 as it was closer to the Ford recommended weight, it's your choice. EATON states that synthetics can make the gear action noisy as these units works with gears only, no clutches. I chose the Lucas grease as it's one of the better ones just below getting into synthetics.

 

I can vouch for that. I wasted $$ on the synth stuff and it was noisy, swapped in the 80w90, nice and quiet.

 

Advice from several of my Auto and Marine Mechanic friends....
You can go from mineral to synthetic, which is OK. But you have to be very careful when going from synthetic to mineral, they might not mix well. If you go from synth to mineral, then you will have to thoroughly degrease the entire diff, including the axles, axle tubes, and axle bearings. Even if you do all that, you still may not get rid of all of the synth additives that have bonded with the metal surfaces and that may prevent the mineral oil from bonding entirely with the metal surfaces.

However, switching is done all the time and I have yet to meet anyone who has complained, that didn't already have oil or wear problems.

More importantly, you should stick with the original viscosity, 85W-140 being the closest to yours, because it determines how much oil film is deposited between the ring and pinion surfaces as well as the bearing surfaces. The 80W90 lighter oil leaves a finer thinner film and can increase wear and diff temps, especially when towing heavy loads where diff temps can get quite high.

This from the Mobil 1 website =>: And as for why mineral oil is 85W and not 75W.... Synthetic group IV is true engineered synthetic and flows much easier at cold temperatures and it doesn't thin out or break down as much at high temperatures such as is generated when you tow heavy loads.