"96 Tahoe Rear Axle Confusion

Discussion in 'Maintenance & Upkeep' started by Conlan Rose, Oct 19, 2013.

  1. Conlan Rose

    Conlan Rose Super Moderator

    So around Thanksgiving time I plan to do some work on my truck including replacing the rear diff fluid, but I keep finding conflicting information about the '96 G80 axle. On the GM dealer order catalog for Tahoe in 96 it specifically says the G80 is a locker, but on RPO decoders it says its a limited slip and even in the owners manual it lists it as one. So before replacing the fluid I want to try to figure out what is the preferred fluid for my rear and if anything else should be done to the rear at this time. I also will be replacing the factory cover with one that has a drain plug so fluid changes will be easier in the future.

    I know that on the newer trucks the G80 is the locker, but in the 90's there seems to be a lot of conflicting information.
  2. 95C1500

    95C1500 New Member

    I believe the G80 is a limited slip for the gmt400s. I may be wrong though.
  3. Conlan Rose

    Conlan Rose Super Moderator

    That is my understanding, but I want to make sure because Limited slips use different fluid then lockers and my fluid options change. I think I'll post a screen shot of the GM doc I have.
  4. 95C1500

    95C1500 New Member

    I don't even have a G80, I've just heard of them referred to as limited slip.
  5. Conlan Rose

    Conlan Rose Super Moderator

    Here is the picture
    Capture.jpg

    - - - Updated - - -

    It depends on context, the current G80 is a locker from Eaton in the 90's there's a lot of conflicting info and no one is sure on when GM fully switched the G80 code
  6. ChevyFan

    ChevyFan Administrator Staff Member

    Really? I've never heard this before. That would be fairly confusing if they changed from a limited slip to a locker and kept the same name.
  7. Conlan Rose

    Conlan Rose Super Moderator

    I think the officially changed it at one point but some older Chevy's like mine have conflicting info because GM used G80 for both lockers and limited-slips/posi-traction rears. And the only definitive way to tell them apart is a tag that would say locker or limited-slip but many get lost during service. My truck has no tag on the rear like it should to indicate either. As you see in the pic of the doc I posted it clearly says locking diff, but most sites say limited slip.
  8. tbplus10

    tbplus10 Super Moderator

    Considering Eaton has been providing lockers for GM light duty trucks since 1973 its possible this truck has a locker, the only way to determine whats installed might be to crack open the differential if you no longer have the tag.
    At one point many automotive mfgrs used the term "locker" mutually for a locker or an LSD.
    In the late 90's when Land Rover and Toyota began offering selectable lockers mfgrs were forced to better define what exact type of differential they were installing.
  9. Conlan Rose

    Conlan Rose Super Moderator

    Guess that is the only way to tell. I was just hoping I would be able to buy the fluid before I opened the rear up. I tired to look around the casing to see if there were any other markings but the only one I found was the GM logo. I know AAM made the limited slips I was hoping to see if they had their letters imprinted. I think there was an indiscernible serial number but I couldn't see it and any pic i tried to take came out blurry or too bright.

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