Advice 94, Z-71, 1/2 ton Rear Diff locker install

[Durfman77]

I have a very nice Z-71 I got from south older lady original owner and runs fine but I want to put a locker of some type in rear and see theres lots of options out there?

They ask for axle splines & how many? Can I look it up without taking axle out??

And what make of locker would be good? It is just a daily driver stock tires etc. just want it for winter etc.

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[78C10BigTen]

Are you sure it doesnt already have a factory gov lock in it?

 

[Curt]

A lunch box locker might work well in this application.(if you don’t have the gov lock).Your RPO codes in the glove box should tell you you axle code,the code will tell you your ratio and if you have a posi or gov lock.

Most 1/2 tons came with a rear 30 spline GM 8.5” differential (AKA 10 Bolt),however,if you are really really lucky you might have the Saginaw 9.5” (AKA Metric 14 Bolt).

I doubt you have the later,but you never know.If you have no “gov lock”,a lunchbox locker might work well for it’s easier installation and lower cost.They are good for average wheelers and 33”-35” tires.

 

[Poppy 87]

I believe that G80 and G86 are the rpo you would see on the glove box label if it is factory limited slip or positraction

 

[Catbox]

I put an Auburn Limited Slip into my 1995 Suburbans rear axle after blowing up 2 of the stock Gov-Lok piles of crap.

It has been in there for a couple few years now and I can tell you it works like a champ.
Apparently there are two versions a softer and a more aggressive version.
My guy puts in the aggressive version and you can tell.
Pulling out of the driveway you can hear the inner tire scrubbing.

But it drives like a champ and I no longer worry at all about the rear letting go again.

 

[BKING33]

I put a Detroit TrueTrac in my Burb. Works great over slip posi and a lot stronger than factory lockers.

 

[Durfman77]

A lunch box locker might work well in this application.(if you don’t have the gov lock).Your RPO codes in the glove box should tell you you axle code,the code will tell you your ratio and if you have a posi or gov lock.

Most 1/2 tons came with a rear 30 spline GM 8.5” differential (AKA 10 Bolt),however,if you are really really lucky you might have the Saginaw 9.5” (AKA Metric 14 Bolt).

I doubt you have the later,but you never know.If you have no “gov lock”,a lunchbox locker might work well for it’s easier installation and lower cost.They are good for average wheelers and 33”-35” tires.

I have the Ten bolt Rear and for sure has No locker now----Just want to be able to put some type of locker in and know axle spline without having to take axle out??? Have to order it anyways after I see what one works best from all you guys,,

 

[Durfman77]

I believe that G80 and G86 are the rpo you would see on the glove box label if it is factory limited slip or positraction

Can I be sure it is a 30 spline from Numbers in glove box? And will the numbers be in wwith all those other numbers there also???

 

[skysurfer]

...and for sure has No locker now--

How do you know this? It would be helpful if you posted a pic of the sticker in the glove box.

 

[Craig Nedrow]

I have a detailed installation of the Yukon lunchbox locker install go here:https://www.gmsquarebody.com/threads/1973-k20-350-to-454-swap.29840/page-3

Starts at post #35

 

[Durfman77]

How do you know this? It would be helpful if you posted a pic of the sticker in the glove box.

I took cover off when I changed the oil in the Diff, Just spiders is all in there

 

[Durfman77]

I have a detailed installation of the Yukon lunchbox locker install go here:https://www.gmsquarebody.com/threads/1973-k20-350-to-454-swap.29840/page-3

Starts at post #35

THANKS

 

[Durfman77]

How do you know this? It would be helpful if you posted a pic of the sticker in the glove box.

I,ll get a photo later today of numbers

 

[skysurfer]

I always thought the G80 was included with the Z71 package but maybe it was listed as a separate line item.

 

[Rusty Nail]

Hmm.

Unknown but thats a great point skysurfer.

My opinion is I sure as he'll wouldn't spend time/money doin that..i mean building that.
I'd buy a complete rear from Craigslist and swap em out -before I made my own- unless it needs some fancy ratio.
There are many. You could save money.