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I have a 2000 GMC Z71 with a fresh installed LQ-9 6.0 and will be having gears installed soon.
My question is .... is the stock posi unit strong enough or do I need an aftermarket unit?
If the stock is strong enough to handle the torque, I won't waste my money, but I remember GM went to a clicker type unit that sucks.
Does 2000 have a good unit, and if not which one should I get?
Detroit Tru Trac or Eaton Clutch type posi. People argue up and down about which one is better. Short answer, replace the factory unit if you plan on playing...
Ive had all 3 and had no trouble from any however the stock unit cannot be abused such as one wheel off pavement and the other on and gas it or trying to do donuts. Straight line use only for it to last. Hell even the father of turbo trucks, "Parish" used a G80 on his for a while as I recall. I personally would upgrade while your at it. Both the others are good units but a few have had some problems with trutrac but I would still use it. Had the Eaton on the turbo truck much later. Had the G80 for the mid 7 run with no issues. Never did have any just upgraded.
I pulled the OE Eaton G80 out of both my half-tons, put in Yukon Dura-Grip clutch style posi-traction. One has a strong 383" gen1 manual trans, I hammer it hard, turning 275/60R20s....Always posi,no problems.
Another Dura-Grip in Tahoe, has 34" tires, 4.56 ring and pinion, and 11 pounds boost, again, always turns BOTH tires, smooth quiet operation on the street. No problems..
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Rumor has it the G80 can be gutted, flyweights cut, made into real posi, for cheap.......
Last edited by Fullpower; 01-25-2018 at 01:43 AM.
Reason: spell
G80 units are garbage. Replace it with one of the aftermarket ones mentioned above while it is apart. They are not performance orientated.
The g80 units are a "limited slip locker" type, long story short it senses one side spinning and then locks the other wheel in IF AND ONLY IF certain conditions are met.
-Over a set speed a flyweight swings out from inertia to keep it from locking, this is to keep it from locking if you hit a patch of ice or something with one wheel while driving over 25mph is the speed limit if i remember right.
-need so much rpm difference between the left side and right side wheel for it to engage BUT if there is too much another lockout function happens to keep it from locking up. This is a very small window from what is needed to get it to lock and what is too much.
-because of the difference in rpm needed the lock up can be and usaully is pretty harsh, pretty much anything other than power braking it will cause a huge thunk/clunk on lockup and will exceed the "lockup rpm window" and not lock up at all. Because of this harsh lockup you end up with huge shock load to the internals of the locker, the carrier, and the axle shaft of the tire that was not spinning but suddenly was forced to when the locker engaged.
Ive seen multiple broken carriers, multiple broken axle shafts, and multiple broken locker internal parts all because of their nature. The most common being in the 8.5/8.6 10 bolts but also all the way up to the aam 11.5's behind the duramaxs. The worst case scenario is when the locker internal parts come apart but the vehicle is still driveable which then gets sucked into the ring & pinion and ruins them also.
10-07-2017, 05:53 PM
1/2 ton rear posi
