What's up with this 3-series carrier? It's NOT a ZT axle, it's a Saginaw (er, American Axle, or whatever the name is now), 3.73, limited slip. I was changing to synthetic oil and opened up to drain and inspect.



It has side gears like a "regular" axle, but also has these centrifugal clutch dogs w/return springs. There is a nice stack of washers on either side of the differential carrier, but no visible cone clutches. Have I not rebuilt enough rear ends lately to catch on to this?



When did this start?

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Later,
Vader
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"What a Day..."
Adobe Acrobat Reader

 

GM calls that posi unit a gov-lock. I have only seen them in 8.5 10-bolts as early as 1983. Very week unit,I have seen parts explode through the rear cover when they break. GM still uses them in new Tahoes. I have replaced three of them this year with aurburn units.

 

Thats a new one on me. Course..I'm not an ASE tech or anything either

 

Me = ASEP graduate and former GM Technician.

I saw one of those things, back when I was wrenching, in a 97 two-wheel drive Suburban. I agree that they are weak units. I wasn't working on the truck but I always made it a point to oggle at vehicular carnage whenever I got a chance. So when I saw the 'Burban come in on a Flatbed I knew I would be treated to some good visuals. The guy that got the RO pushed it in and we heard LOTS of bad noises during the pushing. He got the truck up in the air and we saw a couple of large dents in the diff cover. He took the cover off and - WOW ! The entire thing was blown to pieces. Most of the ring gear and pinion were chewed off and the insides of the carrier were laying in the bottom of the case, thoroughly diced. We couldn't believe the axles weren't broken. Man I love seeing that $hit - when it isn't mine ...........

Laterzzzzzzzzzzzzzzzzzzzzzz

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Matt

1987 GTA L98 MD8 GW6

"Stop Lights timed for 35Mph are also timed for 70Mph"

 

Yep, looks like the gov-lock in the '84 3.73/posi/disc axle I put into my '86...

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damn i have one in my 85 w/4:56s and one in my shed for a spare w/disk

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ICON Motorsports

1st & 3rd
MM Black Diamond 538 F&AM

 

I don't know where "gov-lock" came from, but is an Eaton Locker. They really aren't that bad (can't vouch for early units, but the late 90's and up are pretty decent).

I have seen some "exploded" ones, luckily for me, it was on 4X4's, so I could lock the front axles, and drive it in the stall like a FWD car! But for the most part, they hold up pretty well.

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BCT,

I was hoping to get feedback from the Master. I feel a little better knowing that the later models are "pretty decent". This just turned 9,000 miles and I wanted to go syn on the first change. I also used friction modifier (posi additive), lacking any clear advice from the manual. With the past discussions of ZT axles and the dispute over additive in the planetary diffs, I felt pretty safe using it. At worst, I can open up again and waste a couple of quarts of syn gear oil and refill. The front diff was completely different, the old style open differential I am more accustomed to seeing. The transmission and transfer case are next... yeah, I know, auto trans fluid, but synthetic for sure.

Thanks to all for the replies.

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Later,
Vader
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"What a Day..."
Adobe Acrobat Reader

[This message has been edited by Vader (edited April 23, 2001).]

 

It's an Eaton Gov-Lock. It's real common in S-10s. I have one sitting in my garage at the moment.

It's not very strong at all. It's desiigned for an off-road or other low traction type of application. It won't stand up to pavement lock-ups. It has the weights arranged in such a way that when the axles are turning at the same speed, it's an open diff; but when the RPM difference exceeds something like 100 RPM, the weights operate the clutches.

For a clue to its strength, look at the amount of metal at the right edge of the "window"...

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited April 24, 2001).]

 

What would the operator have to do to cause one of those to explode, like you guys mentioned ??? I caught the pavement lock-ups, but have no clue what that means.

Ron


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'82 Trans Am
'81 Camaro Z-28
'94 Vette LT1 Coupe

 

Do hard launches on pavement




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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

Locking Differentials are designed for off-road, low traction situations like others have stated. The problem with these diffs in a vehicle on the street is the traction that is available. The tires just get too much grip for the carrier to handle on asphalt or concrete. The way the locker works is, it is an open diff until a speed differential is present between one axle and the other. At that time (100 rpm difference) that spring loaded dog mechanically locks the diff. The axles are now mechanically locked together and provide optimal traction, but they will not slip or give for any reason other than a part failure. The problem with it on the street is that it will allow that one tire to go up in smoke and than - BAM - lock the other axle in, which usually results in a destroyed carrier. This is not a good differential to put in a car. Anyone running one in a truck needs to know that they have one and exactly how it works so they don't 'accidentaly' blow the differential apart. The guy that owned the Suburban that I referred to in my original comment, was never told that he had a locker or educated as to how it works (just another example of a worthless salesman). Lucky for that guy, his truck was still under warranty.

Laterzzzzzzzzzzzzzzzzzzzz

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Matt

1987 GTA L98 MD8 GW6

"Stop Lights timed for 35Mph are also timed for 70Mph"

 

Thanks for enlightening me with that information. Wow you would think they would say something, since 95% of those SUVs sold today don't ever see off road use regularly.

Ron


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'82 Trans Am
'81 Camaro Z-28
'94 Vette LT1 Coupe

 

My wild stab from the picture... An Eaton Unit used in Pick-em up trucks and SUV's, the "optional" locking rear.. If i remember. if it notieces a hundred rpm diffence, it locks the axles together, however over 20 mph it will not engage.

In the early mid 80's I think you could get them in GM trucks, and dodges.