Does my 1990 Suburban 1500 4x4 have open or locking Rear Differential?

[motohunter4]

Do the front and rear diffs use the same ring and pinion/carrier? For instance, buying two of the same for front and rear.

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[Vbb199]

Do the front and rear diffs use the same ring and pinion/carrier? For instance, buying two of the same for front and rear.

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Yes usually, 73-78ish couldve been 10 bolt front/rear or d44 front, 10 bolt rear.

Past that in half ton, its all 10 bolt front and rear , unless you get a wild card 12 bolt rear like my 84 k10 had.

 

[AuroraGirl]

up to 82 i read gmc could be found with d44, my 1980 has d44, and my 78 k10 oddly does too. unless the covers are exactly the same as 10 bolt

 

[motohunter4]

Good to know. I have a 10/10 combo like the OP.

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[TubeTruck]

Jack up the rear from the pumpkin so both tires are off the ground. Spin one tire, if the other spins the same direction you have a posi, if it spins in the opposite direction it's open.

 

[Giant Rock]

Open diff. Not the end of the world, but your dreams of an epic mud bogging rig are over.

Seriously though, mine came the same way with open diffs. I needed more traction once in a while so I opted for a lunch box locker up front. Problem solved.

Cool thanks! What are the pros and cons of an open diff? Anything I need to know so I don't fudge it up?

 

[dvdswan]

up to 82 i read gmc could be found with d44, my 1980 has d44, and my 78 k10 oddly does too. unless the covers are exactly the same as 10 bolt

Dana 44

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As you can see between the 2, GM 10 bolt is a little more round at the top and sides than the Dana.


GM 10 bolt

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[Bextreme04]

up to 82 i read gmc could be found with d44, my 1980 has d44, and my 78 k10 oddly does too. unless the covers are exactly the same as 10 bolt

Interesting since our two trucks are so similar. Mine is an 8600GVW with heavy duty front suspension option and 4.10's and came with 10 bolt front

 

[AuroraGirl]

Interesting since our two trucks are so similar. Mine is an 8600GVW with heavy duty front suspension option and 4.10's and came with 10 bolt front

weird you just described my 1980 k25 with 8600gvw with HD front and rear with 4.10 in front and back with d44 front.

Who are you and where did you put my square?!

 

[skysurfer]

Cool thanks! What are the pros and cons of an open diff? Anything I need to know so I don't fudge it up?

I guess about the only pros to an open diff are better street manners compared to ones with some of the available traction-aiding devices, and an open diff allows you to easily install one of the less expensive drop-in lockers like I did.

The down side is their off-road ability isn't good. When a tire loses traction all of the engine torque goes to that slipping wheel and you're stuck. It was a reality check when I figured out that my "four wheel drive" was in fact, a two wheel drive with only one wheel up front and one in back receiving power.

In my case, there wasn't a way to improve my 14b semi-float rear diff that was within my budget, so I chose to work on the front 10b instead. I still plan on doing something about the rear, but it will be after I find a 14b full-float axle.

There are some really good options for improving traction in your 10b rear, but it depends upon your budget and what you plan to do with your truck.

 

[motohunter4]

I'm looking at a posi front and rear setup for street ability. But maybe posi rear lunch box locker front since I have locking hubs.

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[75gmck25]

Most aftermarket locking differentials (at least for my 14 bolt FF) are designed to bolt into an open differential, and the aftermarket ones work much better than the Gov-Lok. Look through some of the choices available from Summit racing. Not cheap, but they work well.

For maximum traction I would add a locking differential in the rear, and an air locker in the front. You want the front one switchable, or it would destroy tires while driving on pavement.

Gov- Lok G80 differentials have a bad reputation because they are designed to lock up when the wheel rpm is only about 200-300 rpm difference between the two rear wheels. At that point the centrifugal force moves the locking pawl out and it locks the two wheels. If you spin up the wheels quickly, the rpm difference will be much higher, and the locker may destroy itself as the pawl tries to lock the axles. It’s a “farm truck stuck in the mud” locker, not a “drag race on pavement ” locker.

Bruce

 

[motohunter4]

With manual hubs you can "turn it off", right?

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[75gmck25]

You could turn “off” a front locker with the hubs. However, with an air locker you can leave the hubs locked when off-roading, and only lock the front differential (from the driver’s seat) if you needed it.

Bruce