budhayes3

iTrader: (19)

I too didn't understand why the trutrac would require a conventional, but a few members here proved it. Bill (trever1t) comes to mind, as his TT didn't lock at the strip with synthetic in it. IIRC, the member here who spoke with Eaton on the phone explained why at the time, but I can't remember the exact reasoning. It did once again have something to do with the synthetics being too slippery though, which may allow the mechanical parts to move too freely or something along those lines.

*EDIT* Something that I have learned from wrenching in the shop for the past 25+ years though, is that automotive theory and reality don't always jive together lol. When I was getting started, I considered the ASE test guides to be the automotive bible, but often time, what works in theory on paper reacts totally differently in the real world for whatever reason. That's where experience and input from others comes into play.

1994Vmax

iTrader: (4)

Nothing works in reality like it does on paper. I have been in the oilfield industry for a long time and trust me, absolutely nothing usually works without a great deal of fiddling or "massaging". Engineering is usually terrible, wrong, or just so far out in left field that when implemented you spend years trying to correct an issue until they finally redesign it.

That said I still question the Locker itself, not the Trutrack. The way it operates should make zero difference with oil choice, "slippery" should be better.

Funny thing with the Truetrac though, it and the Quaife Torque biasing LSD are the same worm gear design. That said, the Quaife works just fine with synthetic lube in it and in fact they recommend the use of it. I know a couple guys with the Quaife in the Mercedes built diff under the LX chassis SRT8's ( prior to the Getrag clutch pack LSD in 09 up) and the instructions recommend the factory synthetic lubricant.

If the Eaton doesn't work though, it doesn't work. Not that I care really as I will never own a torque biasing LSD anyways lol. Funny you guys concern yourselfs with a Truetrac "locking". It can't, or shouldn't anyways as that is not how it works. It just shifts power from the tire with least traction to the one with the most.

And honestly, how many of you guys on here road race your pickup trucks? I am guessing none...... but a lot of you live at the drag strip. Yet you constantly purchase a limited slip designed with the road racer in mind and try and make it work with slicks on a strip. I am on quite a few other forums and it's only these Chev truck boards that want to do this. Anywhere else it's torque bias for the road course, locker for the strip or a clutch pack LSD for the daily driver/ sometimes on the strip or road course. And when I say it that way look at each ones design, how it works and so forth. A road racer wants the tire that has traction out of a corner to grab ( torque bias) a strip guy wants both tires to grab ( locker) and the LSD of cone or clutch design is a in between that is not really good at either. Whatever floats your boat though.

Once I get a locker in the diff of my 94 or grenade my 05's Gov Bomb and replace it with a Detroit Locker I will run good old 75W90 Mobil Delvac and am willing to bet it will work just fine.

budhayes3

iTrader: (19)

I'm still on the fence between an Auburn posi and a Detroit trutrac myself, and I see your point about the trutrac's intended usage. I believe that alot of us here prefer the trutrac for it's non-wearing parts and reputation as a near bullet-proof brute, but I'm just guessing. It seems that those who don't use it are dead against it though, while those who do are very happy with it.

1994Vmax

iTrader: (4)

Don't use an Auburn Cone Gear one, really just don't. It's a silly design that just wears out very quickly if you drive hard ( like me) and then you are stuck replacing the entire carrier because it's the wear component. I have worn out a couple and will never do it again.

I understand to that the trutrack is pretty well maintenance free in design and will sort of work for a daily driver strip machine. A lot of guys don't like locked diffs because they are harsh ( I love it though, and I live in the land of ice and snow....... but maybe I am weird lol). I do understand it, but I am just no fan of the torque bias diffs operation.

For a normal daily driver I would just use a clutch plate LSD. At least when you fry it ( which a cone gear one will do just as quickly as a clutch design) you can yank the cover, remove the springs and change the plates. Plus you can add more plates, less plates or change spring rate for however agressive you want it to be or not to be.

hog

In a clutch type posi, I have always had to add a friction modifier, which used to come from whale oil. Without it, it was almost impossible to perform slow figure 8's on pavement.

The G80 Eaton Gov lock also uses clutches, but those clutches are not supposed to slip like they do in a clutch pack dif like the Eaton Carbon LSD. I'm pretty sure the Gov bomb doesnt call for modifier.

I dont see lube making much of a difference in actual Lockers such as the Detroit locker or lunchbox lockers like the Lock-rite and No Slip traction system.

I dont really consider the Lockrite a locker either, it really is a torque sensing differential, it doesnt lock or unlock like a locker, or slip like a clutch type dif.

Truetrac
Exploded View - Inside the Eaton TrueTrac Differential - YouTubeEaton Nospin(detroit locker)
Detroit Locker - YouTube
Eaton posi and others Posi-clucth LSD, 200, 400 and 800 lb preload spings available, 200, 400 clutches are Carbon, 800 lb preload clutches are NOT Carbon.
Eaton Applications - YouTube

Lots of choices, all have their pros and cons. I can see why GM chose teh G80 Gov lock for a stock non-performance application. Locks when needed, unlocks at 30mph so vehicle doesnt become unstable in winter at speed.
Sucks for performance.

peace
Hog

1994Vmax

iTrader: (4)

Awe the good old gov bomb. Yeah it's been covered by GM on here and FSC ( I am also a member there under a different name) why it doesn't like friction modifier. There is even a GM TSB stating to not use anything other than just gear oil in the Gov lock equipped diffs. It delays engagement of the flyweight which is odd but true. I noticed after adding it to a 10 bolt Gov lock it immediately stopped functioning correctly. Just the way it goes I guess.

I totally agree about the rest. I have synthetic in my Honda atv's front diff which incorporates a Detroit locker now ( basically just like the lockrite design wise) and it works perfectly.

And back to the G80, well it is what it is and I will leave it at that.

Ferocity02

iTrader: (59)

Bringing this one back from the grave.

The manual indicates to fill the diff until the fluid level is 5/8-1-5/8" below the fill hole. People on here say that around 2 quarts will work. A lot of us use pinion angle shims to help point the front of the diff down which means the oil will reach the fill hole faster.

When I put just under 2 quarts (1 qt 30 oz) in mine, the level was about 1/2" below the fill line. If I put in the the full 2 quarts the level would be around 3/8" below the fill line.

So my question is, should I stick to the 5/8-1-5/8" recommendation, or the ~ 2 quart recommendation? If I did 1-5/8" that would be like 1-1.5 quarts, seems awfully low.

Slow91z

It's just not that critical