Factory Locker

I had taken my 97 K1500 to the dealer to have the rear end looked at due to excess clunking and oil leaking. The problem was that i put too much gear oil in it and the gasket wore out so they fixed me up with a new gasket for $148, still cant figure that one out. but anywho they also told me that my truck has a factory rear locker, any one else have this or heard of it? It's a 9.5" 14 bolt rear end and the guy that worked on it told me that it would only engage when put in 4-Lo, which could explain a very noticable clunk there also.

You have a 14 bolt in a 1500 series? Never heard of such a thing. All C/K 1500's come with 10 bolt 8.5 semi floating rear ends. A 14 bolt is a full floater used on the 2500, 3500. If you do indeed have a factory installed 14 bolt on a 1500, it will be the first I ever heard of. And also your 4hi and 4lo only engage the front. the rear is always engaged.And yes it's clunks when locking the frt diff.

They did put the light duty 14 bolt in some of the 1/2 ton trucks. I have seen few.
The rearend does not care if the truck is in 4 wheel or not. It will act the same either way. If it is a factory posi you will hear a "clunk" when the posi engages. It is the nature of the beast.

Forgot to mention. The light duty 14 bolt does not have full floating axles, it is semi floating (like the 10 bolt). The heavy 14 bolt is full floating and also has a remove-able pinion.

The lighter 14 bolt only has the 9.5" ring gear, while the bigger one is a 10.5" ring gear. There is an 11.5" ring gear 14 bolt, but that one is pretty rare.

If it is factory, it is Posi-traction. It will work if in 2wd, 4wd, whatever. There is no way a locker will only work in low range, 4x4. And, a posi works differently then a locker does.

I would try taking it to a rear end specialist or another mechanic and have them take a look at it.

I am the second owner of the truck, it has a 14 bolt 9.5" rear, 5 leaf springs, and a class five hitch, all were from factory the previous owner did nothing to the truck. It was used to haul a truck bed camper so that could be why it has more heavy duty features. if it does have posi-trac then when ever i power brake both wheels should try to spin but it's always only one; however when i just floor it and cut the wheel both wheels always spin. Also i had a friend stand out side the truck while i was in 4-Lo and he could plainly see 3 tired spinning at once with the rear two constant and the fronts alternating.

I am the second owner of the truck, it has a 14 bolt 9.5" rear, 5 leaf springs, and a class five hitch, all were from factory the previous owner did nothing to the truck. It was used to haul a truck bed camper so that could be why it has more heavy duty features. if it does have posi-trac then when ever i power brake both wheels should try to spin but it's always only one; however when i just floor it and cut the wheel both wheels always spin. Also i had a friend stand out side the truck while i was in 4-Lo and he could plainly see 3 tired spinning at once with the rear two constant and the fronts alternating.

You have a G-80 locking differential and they do clunk when they lock. This diff works as an open diff until there is a 200rpm difference in the rear wheel rotation. At this point the rear diffrential has weights in it if I am not mistaken that lock the diff and it will clunk sometimes. The reason only one spins when power braking is that the design of this diff only alows it to be locked at low speeds. Once the vehicle is traveling or the wheels are spinning at a certain speed it will automatically disengauge. I don't know what the exact speed is, But if you search the net for info on Gm's G-80 locker you should find all the info that explains how it works.

These units are junk. Under easy use they hold up ok but if you get good and stuck you can blow one up before you know it. I'd retrofit with an auburn or detroit unit. These also perfrom better and you dont get the clunk.

I have been more than stuck several times to the point where i have had to be pulled out by a back hoe, so im pretty sure it's doin ok for a factory unit. Not saying a auburn or detroit locker wouldn't be better but mine has held up fine under heavy abuse.

Its a limited slip or posi, not a locker. If its a 14 bolt, its not factory, and if its a locker, then someone changed it out.

i have been told by a more knowledgaable mechanic that it is basically the same as a posi-trac unit, just a "less effective" factory version. Absolutly everything about the truck was 100% factory stock when i bought it. Including the 9.5" 14-bolt rear end and the class five hitch.

I was told by a more knowledgeable mechanic that it is basically a posi-trac unit, just a "less effective" factory version. Absolutly everything about the truck was 100% factory stock when i bought it. Including a 9.5" 14-bolt rear end and a class 5 hitch. Jealous?

I have a class V and we've owned it since mile 0. It was a part of the package. I will tell you this, the chevrolet suburban does not come with that axle stock. That was probably a special request from the factory.

yeh but im not talkin about a suburban, and i know 2 other people that have the same axle on a 1/2 ton silverado. and yes im sure it isnt standard issue but also not a rarity by any means.

yeh but im not talkin about a suburban, and i know 2 other people that have the same axle on a 1/2 ton silverado. and yes im sure it isnt standard issue but also not a rarity by any means.


You are absolutely correct !! I have one and I bought mine new. In the brochure it is listed as a heavy duty chassis package. On the window sticker it shows it as an otion for something like $225.00 (I would have to look for sure). The package consists of the 14 bolt semi- floater and an extra leaf spring and it could be with or without the G-80 locking differential. The springs and diff are the same as a 7,200 GVWR 3/4 ton. They even use this as the standard diff in the 8,600 GVWR 3/4 tons exept they use bigger eight lug axles. It was an option to get the 14 bolt full floater with the 10.5" ring gear.