Could this be what is in our 1994 3500 dually 6.5TD ? It locked in so good that we pulled a trailer that was loaded and weighed 12,000 lbs. along with the truck loaded and weighing about 10,000 the right wheels were in pure mud no road under it and left were on the road. It pulled the entire load with left wheels only. I've had new limited slips that could have never done that, but then again they were in 12 bolt rears so definitely not as much clutch surface as a big truck 14 bolt rear. What would the numbers be for the rear ? our glovebox has about 50 number combos in it. all just in order.
Bigger axle, more clutches that are also bigger in diameter and holding power which means more power transfer before clutches are over powered. The GovLoc is a lot sturdier in bigger axles but still a clucky beast at times.
Hours of sitting here trying to research this here is some of the comments I found...
GM offers the Gov-Loc, which is a GM OEM full carrier locker available in their Corporate axles. This unit normally operates as an LSD, but a counter-weighted locking mechanism locks the side gears together when the wheels have a speed differential of something like 100 - 200 RPM. It makes a very interesting "BANG" when it engages, and if you ever saw one you would be afraid to have it engage. They seem to work well, though, and GM has offered it for decades.
Gov-Loc is a locker, and an LSD. There is a counter-balance in there that locks the driver-side side gear to the spider gears, effectively spooling the diff when a certain speed differential thres hold has been reached. That's a locker. I'll open one up and show you how it works. Scary stuff. I've disassembled a few of them. My Suburban has one, and it freaks me out every time it engages. I also found one that said the Gov-Loc only came in the GM corporate rears, which as far as I remember is the big 10 bolt. I thought the 14 bolt was a Dana or AAM ? What years did they use what ? Our 1993 3500HD 15,000 GVW is supposed to be a Dana 80 What would be the 14 bolt in our 1994 3500 10,000 GVW dually ?
Not true. All 2002 Z28's have the Torsen unit. I believe the 01's do too.
And:
A new limited slip differential is available on Ram Heavy Duty. The helical gear design provides torque biasing and eliminates the "chatter" found in friction plate designs. The system requires no lubricating additives.
Nothing worse then then Non-GM numbers and data. It can be misleading. While the 99 ups may have came with a Torsen standard. The 1994 to 98's it was a option.
The problem here is getting my greedy little paws on a good 4th gen rear end with a LSD unit. Everyone wants a arm and a leg for one. Same problem with the seats if there decent & the right color. Heck even for Steel 16 inch wheels off them (close enough offset to a S-10 4x4) people want almost as much as after market steels go for new! Charles I own way to many vehicles to post a sig list.
I've been "lurking" for a while now. Recently acquired a new (to me) Chevy:
1998 Silverado Z71 EC.
I'll throw a question in, all responses are welcome. From the build sheet, I gather the truck came with a 3.42 gear ratio. My question is: Does this vehicle have a locker or an LSD, or is it an open rear diff?
I have nothing to add to the current debate - seeing how this is my first Chevy. Kind of "willed" to me by a living stepfather with Macular degeneration. All options & 56,000 miles. 5.7L Vortec. Only current mods (by me) are K&N FIPK 2 kit and Rhino liner. Still on the learning curve, as it were.
You have to look for the G80 code to know for sure. The G80 is a locker, snoman has been describing it wrong, an LSD when it connects the rear wheels together doesn't connect them 100%, it will allow some slip between that is why it is limited slip. The g80 locker uses clutches yes but locks the wheels 100% together with no slip.
What was the one called that was available for 10 bolt 7.5" rears ? Was that still a gov-loc ? That is exactly what we put in our El Camino... I didn't know what that contraption in there was. I always had just plain old LSD'd usually in my 9" rears (in Chevy's).
Alas, no G80 codes. Assuming these cryptic three character codes are the same ones used on the build sheet obtained from the dealer using my VIN number, what does "GU6 - REAR AXLE 3.42 RATIO" mean other than 3.42 gears?
What about "Z82 - HEAVY DUTY TRAILERING EQUIPMENT"?
and what exactly does "Z71 - OFF ROAD CHASSIS EQUIP PACKAGE" include anyway?? Is this just Bilstein shocks (which are damn nice by the way)?
Also - are there any other locker / LSD codes that could be in this alphabet soup?
It would be nice to know that Chevy thought enough of the Z-71 off road package to at least include an LSD! Nissan did (last vehicle was 92 SE King Cab 4x4).
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