Why doesn't G.M. put more G80 Rear Differentials in their 4X4s?

My wife and I bought a 1998 Gmc Jimmy SL 4X4 (AT & 4 door) GU6 3.42:1 ratio, we took it out years ago 4x4ing, and I was some what disappointed. It got stuck in icy ruts, needed people to push us out. On heavy acceleration only the right tire usually spins.
So any way, I did like the 1998 GMC Jimmy on the road when slippery conditions were present, four wheel drive is easier to drive than 2 wheel drive in wintery conditions.
So I told my wife as soon as I found a vehicle with manual tranny, that I liked, I would buy it. So this year I found a 1999 GMC Jimmy SL (5 Spd. Manual & 2 door) and bought it.
So I took the 1999 GMC Jimmy SL 4X4ing, it performs way better than the 1998 GMC Jimmy in 4X4. Even on heavy acceleration both tires will spin or grab for superior traction.
So then I looked up rear ends for Jimmy’s on the internet, after some research, and verification (RPO code in glove box), my 1999 GMC Jimmy 4X4 has a Eaton 10 Bolt "G80" (GU6 3.42:1 ratio) locking rear differential.
What a difference, the G80 rear diff. is way superior to any rear diff. I ever drove by General Motors.
So why don’t they put this rear end in every 2 wheel drive truck and 4X4 truck they make? The G80 Locking Rear diff. RULES.
You can check the " G80 rear differential" on "You Tube" for your self.
These new G80 rear ends are built stronger than G.M.s previously, "grenade" type rear ends that blew up!
A G.M. 4X4 with a G80 Rear Diff. is the proper way to build a 4X4!

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3 Responses to Why doesn't G.M. put more G80 Rear Differentials in their 4X4s?

  1. alex k June 16, 2010 at 7:13 pm #

    my guess would most likely be due to cost… not every jimmy is expected to see off road usage so it only makes sense for some of them to have a superior differential as an option.

    soft roaders would prefer the lower MSRP
    off roaders would check the box for the eaton 10 bolt

  2. pacman28m June 16, 2010 at 7:13 pm #

    I agree that the G80 is good in all rear drive trucks. I live in the snow belt and it gives better traction in snow and ice. But some people just don’t know any better. and when dealers stock trucks for their lots they like to have a little bit of every thing. I like the g80 in my trailblazer as compared to my limited slip in my Ford F250

  3. Older1 June 16, 2010 at 7:13 pm #

    GM will put in as many as are ordered by the dealerships. The dealership orders the vehicles equipped with specific "bargain" packages. In other words they get a good deal on specifically packaged units. A lot of times the "economy" package does not include G80 locking differential, the all-terrain tires, off-road suspension, trailer package or HD cooling.

    Example: 1989: My dealer general sales manager ordered 6 1990 GMC full-sized Jimmys. They were all equipped with 3:08 gear ratios, street tires, no G80 locking diff. The vehicles were useless in the dirt or off road. They sold 2 of them from 9-89 to 2-91. I bought one in April 1991, brand new, First thing I did was purchase the G80 carrier and install it. Then I put some 11:00X32 X15 BFG AT. tires on it, well, I’ll just say that tall gears and tall tires made for a sluggishaccelerationn but it gets better gasmileagee than the same truck with 3:73’s. But, the locking differential makes the difference in off-road terrain.
    Prior to purchasing the full sized Jimmy I had a 1986 S-15 4×4 pick-up. It did not have G80 locking diff. I got stuck twice in terrain that should not have been a problem. I liked the truck but it was not an off-roader without the G80 option.

    The RPO build code G80 just ID’s locking differential option. Design changes like the later ones will still be G80.