More on GMC Sierra - 4WD without limited slip?

[DJJ]

My brother and I got into his rear differential today, and I would bet my life that it's not a limited slip. It had the ring & pinion, and the 4 gears arranged in a rectangle, and that's it. Wouldn't a limited slip have additional parts in there, or was there something I didn't recognize? Based on my research, I believe it's a Dana product.

Isn't it kind of odd that a 4WD wouldn't have limited slip?

[Art Eatman]

Unless it's special order, very few vehicles have a locking differential.

I haven't been inside a GM locker for a helluva long time.  About forty years back they changed from using tapered ramps to a clutch-pack deal with a Bellville spring.  Dunno if it's the same today, but it would be very obvious if some sort of locker was in the diff.

Art

[Chuck Dye]

When I ordered my Yukon, limited slip - labeled "locking differential"- was an option.

[BozemanMT]

yep
that's true
most 4wd's from the factory don't have limited slip.
To be a serious 4wd, you have to add it.
or not drive in bad places.

[onions!]

A lot depends on where you live.

Around here 2wd trucks are special order & posi is common.

Look inside the trucks glovebox.You'll find a white sticker about 3x5 inches.The top portion is covered w/three character alpha-numeric codes.If the code"G80" is there the truck was equiped w/a limited slip rr diff.

If the truck was built between 1973 & 1999 then,unless it's a one ton dually w/a very high GVW the axle is one of three GM corporate axles.Sourced through GM Powertrain(Eaton),they came in 8.5in,9.5in,& 10.5in ring gear diameters.The first two use a C-clip to retain the axle shaft & have either a round(8.5in) 10 bolt cover or an irregular egg shaped(9.5in) 14 bolt rr cover over the differential.The 10.5in axle uses 14 bolts on the diamond shaped rr cover,has a removable pinion housing,& 8 bolts to hold the axle shaft to the hub.This last axle is what's called a full-float design.

[brimic]

My Trailblazer has the GM locking differential. I had to special order it.

[Guest]

My 2002 Subaru Forester S has AWD and a limited-slip differential on the rear axle. See, I really didn't buy the fancy model just for the big sun roof, 16-in. wheels and cheap heated leather seats.  

John

[richyoung]

"I dunno but I been told...."

...that most 4X4 trucks have limited slip on the FRONT axle, and an open diffrential on the REAR, unless custom ordered differently.  Apparently, limited slip at both ends has a tendancy to crawl off of icy pavement sideways, especially at "too fast" speeds.

[HankB]

Most 4x4s don't have limited slip or locking differentials. Integrated 4-wheel ABS systems are taking their place today, and are probably as good or better if you're using your 4x4 SUV as foul-weather transport on pavement. For serious off-roading . . . I'm not so sure.

My old '84 Bronco had limited slip axles both front and rear, but a front limited slip was not an option when I bought my '93 Explorer - rear only.

One easy way to determine if you actually have limited slip is to put the vehicle up on a lift and manually rotate one tire - if the other tire on the same axle turns in the same direction, it's got limited slip. If it turns in the opposite direction - it doesn't.

[onions!]

Most 4x4s don't have limited slip or locking differentials.

Mmmmm,like I said,must be a regional thing.I asked the sales manager @ the GMC dealership I work at what percentage of light duty trucks sold were equipped w/a posi/limited slip rr axle.Expecting a figure of around 30% I was suprised when he told me"Unless it's a special order (fleet) or a stripper(no options-AKA a "beer can") all the trucks we get come w/G80(posi)".He told me that it's part of an option package that's so popular that they just order them all w/it.Basically it comes to a percentage in the mid nineties.

I can see where some of the confusion exists though.Before 1990 options like external engine oil,transmission fluid,& power steering coolers were almost unheard of.I forget which recent year it was but A/C(!) became standard not too long ago.You have to order it as a delete option to not get it(same w/the radio).