GMC Repair: rear locker or limited slip, eaton elocker, locking differential

Question
i have a 2000 gmc 1500 5.3 4L80e and 3.73 gears.  The rear is a 8.5 that is stamped on the inside.  Is there a locker or limited slip that will fit?  I can not find any other tag number.  I want a limited slip at least.  when got a locker it would not fit through the window.  The parts guy at dealer has the same truck with a limited slip and 4.10s.  when he ran my vin it didn't even list a part for a limited slip.  So is this just a stick in the mud or do i need to look at different year products.

Answer
Hi
I'll first say, if your wanting to go back totally stock,. itis possible...
That being said, if your looking for alternatives OTHER than stock, I'll HIGHLY recommend an Eaton ELocker electronic locking differential.
The price is ABOUT the same as the entire package you'll have to purchase from GM, which also will be piece by piece.
The Eaton will come as a kit. You'll have the option with the Eaton of Locking or unlocked. All at your fingertips.
It is used STOCK in the Hummers, but it IS avalible for ALMOST any other application.
Here is a web site to check out from Eaton....
http://www.eaton.com/EatonCom/ProductsServices/PerformanceProducts/Products/Diff...

You can also do a websearch on this and there are other brands so I just found out.

I am in NO way endorsing these products over the OEM Differntial that is installed in your truck now, but I know needs change so this is my advice
I do hope it helps in some way
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Good luck
Pawl