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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Rear Drivelines, Drive Axles and Gearing => Topic started by: 305chevy c-10 on August 09, 2009, 12:48:03 AM
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I'm confused i wanted my truck to have Posi traction so i went and bought what i thought was posi i reckon ...i had an open diff....i know that much ....so i bought another one ...i told the junkman i waned a posi for my 8.5 10 bolt and he sold me one supposedly...........i think other wise ...my truck will spin both wheels on dirt or gravel but only one one the pavement ....sometimes it will burn both of them if i start it on some loose ground first an stay on the gas hard ........but just from a stand still on pavement it wont spin both ....now my question is am i talking about three diff types of rearends ..posi....LSD.......gov loc if so which one does it sound like i have .......or could it be i need thicker fluid for the clutches to lock ...........boy was i mad when i got this put in and it didnot leave those = signs in the road .. ??? ..just one long ------------------ >:(
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Yeah that's the bummer about buying a used LSD (Positraction was the Chevy name for their limited slip system until they brought out the Gov-lok, which is a different type of unit). Basically, yours is worn out. I did the same thing when I bought a junkyard 3.40 Gov-lok 12 bolt. The Gov-lok was seized up and useless.
To break it down, the Gov-lok and Positraction are both limited slip units. Here's how the Gov-lok works:
http://iwerearendsonly.com/resources/resources_govn-r-lok.htm
^Don't mind the mis-spelling. That's the same shop who put in a rebuilt pre-1973 GM Positraction into my truck just last month. That's a storey in itself but anyway.
The Positraction style is the previous version of the current Eaton clutch-type LSD they make for the aftermarket now. Like I said above, that's what I have in my truck. It uses spring pressure on clutch discs to make the LSD action happen. I don't know why GM switched to the Gov-lok but it might have been for smoother action when 2-tire grip wasn't required.
You can buy rebuilt Gov-loks or even new take-out units but they aren't typically very strong. But if you aren't into serious mud bogging, off-roading or racing or are looking for inexpensive, you might be able to find one on Ebay or buy an Auburn LSD (which is another variation that uses cone-shaped spider gears that push out against the metal case to get the tires to lock together) for about $300 on Ebay.
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Click (http://www.youtube.com/watch?v=KbMZ9vcYVSg&eurl=http%3A%2F%2Fvideo%2Egoogle%2Ecom%2Fvideosearch%3Fhl%3Den%26q%3Dgov%2Dloc%26um%3D1%26ie%3DUTF%2D8%26sa%3DN%26tab%3Dwv&feature=player_embedded)
Limited slip is posi. The Gov- Lock is imo a waste of $. Pull your cover off and take some pix so we can see what you bought.
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mine looks just like this one ..with 273 gears
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Yep, that's a Gov-lok.
Is GM STILL putting those in trucks? Is that what the current G80 option still is? I've read articles touting how good the G80 vs Dodge and Ford products but I'd be shocked if it's still the 'good' ole Gov-lok setup. Wow, Eaton sure has made a few dollars from that. The locking action is neat and all but it's easily overcome with engine power. Why don't they use Torsen diffs like the older Camaro SS's and such had?
I remember my 81 2wd Jimmy having a Gov-lok. In the cold Canadian prairie winters, it would get all choppy on the inside wheel until it warmed up. And if I was on slippery surface, I could hear it clunking away back there as it tried to lock and unlock. The one that was in the rearend I put in my truck last year was wiped right out. The cam gear that the thin rod is supposed to engage had all kinds of stripped and broken teeth.
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Every G80 Limited slip GM produced is called Positraction. Regardless of whether it was a Eaton LSD clutch type or Gov-Loc is it still called Positraction, which is GM's name for a limited slip.
For the application they are made for the Gov-Loc they work fine. They are not made for Drag racing. They are load sensing and are still used today.
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Right you are, Capt. Chevy has called their LSD system, regardless of type, Positraction forever. My mistake. Do they actually use that term 'positraction' anymore? Whenever I see a window sticker it just says "Locking Differential". The new Camaro has a "locking diff" avail. on the V6 cars and standard on the SS. Would that be a Gov-lok? Pretty powerful car for a Gov-lok but they wouldn't put it in if it couldn't handle the task I guess. The Corvette has what they describe as a "limited slip diff."
That's an interesting vid though showing how even a limited slip wouldn't get that Ford up the hill with those rollers on the drivers side but a G80-equipped truck did.
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the Camaros used a torsen diff.
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my 03 yukon xl has a gov loc and its always clunking and driving me nuts! ive got one in the 82 ta right now cause i blew out the guts of the original rear and needed to get it on the road so i bought a used s10 govloc and 3.73s with axles for like 250 so far its holding strong lol its been through many hard launches and 3rdgear burnouts.
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So would you say buying a reman'd gov lock unit would be a waste of time? I dont plan to drag race this truck or anything I just need the additional traction going down dirt roads around here they get pretty washed out.
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Why not just get an Auburn or an Eaton?
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I've been told by many, many rear end shops the G.M. Gov-Loc is junk. I know on E-Bay and local classified ads they are mis represented as Eaton Positraction units. I had one a very short time in my 1984 C-10 with a mild built smallblock and destroyed it after a few power brake sessions. I replaced it with an Eaton Positraction, I believe part number ended with 559. I would definetely save time and money and buy the Eaton. The Eaton unit loves to make 2 long black lines on the pavement. Ken
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I've been told by many, many rear end shops the G.M. Gov-Loc is junk. I know on E-Bay and local classified ads they are mis represented as Eaton Positraction units. I had one a very short time in my 1984 C-10 with a mild built smallblock and destroyed it after a few power brake sessions. I replaced it with an Eaton Positraction, I believe part number ended with 559. I would definetely save time and money and buy the Eaton. The Eaton unit loves to make 2 long black lines on the pavement. Ken
It's not really mis-represted. The G-Bomb is made by Eaton for GM.
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Reason I asked is I could get a reman'd one for about half the price of the next step up posi. I am glad to know that now, I'll just stay with my factory one for awhile longer.