GM Pickup Trucks With G-80 Locker Read This

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Originally Posted By: FastLane
There was no locker back in 1991. It still had the G80 limited slip. The eaton G80 locker came in 1999.
Are you referring to a specific model? Or are you saying the govloc came out in 1999? My 83 k20 has a semi float 14 bolt and govloc differential. The 88 suburban I had for a very short time also had the gov loc differential. In fact it had a new rear end because the original gov bomb exploded on my neighbor when he had one wheel on dry pavement and the other on ice .... Which is usually how they blow up. Terrible idea, the gov loc, it is. "hey guys! Lets let the one wheel get up some good wheel speed, then we will let lock up like BAM! Nothing bad can come from that, right?" The clutches are there to keep it from blowing itself up or breaking an axle when it locks up. To me a little friction modifier to help those clutches slip a little bit can only be a good thing. That is, if you can even get the darn thing to lock up when you actually need it. Seems like I spend half of my time plowing whishing the silly thing would work. Seems like if I can get it to lock up once, it will work half way decent the rest of the day, but getting it to lock up that first time can be a real chore.
 
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CKN

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Originally Posted By: Silverado12
Originally Posted By: SteveSRT8
I cannot challenge anyone's results. But I have owned more than a few Silverados here. In the G80 models we never did anything different, and some of them were never touched. Never heard or noticed a peep out of them, I don't really think a 1991 TSB has any bearing (pun intended!) on this "issue"...
That def makes me feel better knowing the G80 can hold up for a long time. I'm now thinking that the oil probably wouldn't have looked much different at higher miles.
This is BITOG-YOU MUST change it 4 times more often than needed.....JUST because!
 
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Changed the G80 fluid early and about every 30K miles in my '06 Sierra 1500. Used mostly Amsoil 75W90. Stopped locking at about 115K miles. No broken parts or noise, rather, it appeared the clutches wore out. Replaced with a Eaton Truetrac, which I like better.
 
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Originally Posted By: FastLane
There was no locker back in 1991. It still had the G80 limited slip. The eaton G80 locker came in 1999.
This is false. G80 is the code for limited slip differential. The GovLock has been available as well as other traction aiding differentials under the G80 code since at least the 70's.
 
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Originally Posted By: FlyNavyP3
Originally Posted By: FastLane
There was no locker back in 1991. It still had the G80 limited slip. The eaton G80 locker came in 1999.
This is false. G80 is the code for limited slip differential. The GovLock has been available as well as other traction aiding differentials under the G80 code since at least the 70's.
I am saying the current EATON LOCKING DIFF was not available. There was a limited slip previous to 1999 and I was under the G80 option code. Totally different beast. The current G80 is NOT a limited slip. It is a locking differential.
 
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Originally Posted By: FastLane
Originally Posted By: FlyNavyP3
Originally Posted By: FastLane
There was no locker back in 1991. It still had the G80 limited slip. The eaton G80 locker came in 1999.
This is false. G80 is the code for limited slip differential. The GovLock has been available as well as other traction aiding differentials under the G80 code since at least the 70's.
I am saying the current EATON LOCKING DIFF was not available. There was a limited slip previous to 1999 and I was under the G80 option code. Totally different beast. The current G80 is NOT a limited slip. It is a locking differential.
Still false, the GovLock mechanical locking differential is factory installed on my 1976 and 1985 12 bolt and 14 bolt axles. Eat on started producing them later, the Eaton part is an identical service replacement part for the earlier GM model. Also the GovLock and Eaton "Locking" differential are not actually lockers. They use differential wheel speed to apply pre load to clutch packs to increase power delivery to the slower wheel. A true locker will only let a tire travel faster than the rest of the drivetrain, never slower. An example of this would be a Detroit Locker (now also owned by Eaton), the GovLock and Eaton "Locker" are actually mechanically assisted/actuated limited slips.
 
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Eaton's 'Gov-Lock' operation is mechanically quite simple: https://youtu.be/tTGZOJQQBeE Hypoid lubricant gets worked pretty hard. I change my FF early as a matter of course. Typically find a fair amount of metallic shavings in the fluid and on the covers' integral magnets during initial renewals.
 
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