Welding or Lunchbox front Diff locker for K10?

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AlexK10

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Hi, I have a beat up K10 (1984) that I've been fixing up. It has a 305 sbc, 700R4 trans and transfer case with wheel lock front hubs.

Anyways the other day I was messing around a steep dirt track testing the 4x4 which works great. However on one section a front tire lost traction and obviously spun and got me stuck.

Guess its designed that way from factory were one side looses traction and you dig a hole and get stuck?

My intended use for the 4x4 is around slippery boat ramps and any other scenario where I would need it while on dirt/off the pavement. I am not into hardcore off-roading or mudding or climbing etc therefore 99.9% of the time it will be on 2x4 with the factory rear setup back there on pavement.


Anyways: Is the front internal diff ring/pinion carrier assembly the same as the rear were I could find a used diff, weld it and swap the original so I do not destroy the original differential by welding it?

What specs should I look for when buying a used front differential for a 1984 K10?

If sourcing a used front diff or rear diff that would fit the front is impossible, what other options do I have before looking into a 250-300$ lunchbox locker for the front?
 

AlexK10

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Any ideas on the specs of the stock K10 front diff?
 

Vbb199

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Since it's a 84, it'll more than likely be a 10 bolt Front diff, if nobody changed it for something else.

It's a 8.5 ring gear.

Same as your rear axle, probably also a 10 bolt (pics help)

I wouldn't recommend welding the front diff, because turning at that point with the hubs locked in will be a big time pain in the ass, and given enough power applied, on a turn, you'll bind the axle shaft and break it.

BUT if you do want to weld it, it's best to just unlock 1 hub to make turns when in 4x4.

May consider air lockers for what you're wanting... Which, I know, are expensive

ARB, grizzly, etc.
 

Vbb199

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And the front axle is a open diff. power is only applied to 1 tire at all times.
 

Vbb199

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Oh, what gears are in the axles?
I have a 3.42 r/p set and carrier, from a 10 bolt Front, if you're looking for something to weld and play with if you do want to go that route.
 

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If you don't need 4x4 often, but need absolute traction when you do happen to select 4x4, welding up the diff is probably a decent option.
 

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What specs should I look for when buying a used front differential for a 1984 K10?

If sourcing a used front diff or rear diff that would fit the front is impossible, what other options do I have before looking into a 250-300$ lunchbox locker for the front?

Sounds like you have a regular, garden variety open differential in the front. Like all forces in nature, power follows the path of least resistance so when you have a tire on a low traction surface that's where the power goes.

Without seeing or knowing anything else about your truck, I'm guessing you have the factory 10 ten bolt diff front and rear, with 8.5" ring gear. The ten bolt diffs came in 28 spline and 30 spline varieties. You need to make sure you match up correct number of splines or whatever you put in there may not fit.

If you change the gears or swap the whole axle for one with limited slip be absolutely sure it's the same gear ratio as the rear diff. I had an '84 K5 years ago. The rear end, with factory 2.73 gears, blew up so I swapped the whole axle with one with 3.73 gears. I couldn't use four wheel drive with risking tearing everything apart until I swapped the front axle with a 3.73 diff also. Somebody correct me if I'm wrong, but I believe you can have a variance of up to 0.10 between the front and rear gears. For example, you can run a Dana with 4.11s in the rear and corporate with 4.10s in the front still be okay.

There are several ways to go about what you want:

1) Without swapping anything you could simply install a limited slip differential in place of that open diff. I wouldn't go with a used one because, depending on how much abuse its taken, it may have little life left to it or not work at all.

2) Find a whole axle with a locker or limited slip and swap it. As I said above, be sure the gear ratios are the same as the rear axle.

If you're willing to spend a little bit of money I would look into the Detroit True-trac limited slip differential. They're around $550 for the ten bolt diff units. I am eventually going to install True-Tracs in the front and rear on my '80 K25. They are appealing because they are completely gear driven. No clutch packs and springs, it is always fully engaged. The instant one when one wheel looses traction torque is diverted to the wheel with traction before the low traction wheel slips. But if you really not using it often, then stick with a cheaper option.
 

AlexK10

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For some reason I'm not getting reply notifications on my email for this thread.

Anyways, Thank you all for the suggestions.

I also researched the options I have before welding and found what its called a "mini spool", which range from 70$ to 130-150 for the more expensive Yukon. This will give the same locked 100% of the time result as welding, except for being reversible (not trashing my pinions). With hub locks free the diff and axles wont spin or lock the wheels on rotation so 2x4 driving will be the same as now.

Any experience with these?

Or the next step up a "full spool"? But that requires the carrier to be removed, gears shims reset etc etc.
 

Vbb199

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Sounds like you have a regular, garden variety open differential in the front. Like all forces in nature, power follows the path of least resistance so when you have a tire on a low traction surface that's where the power goes.

Without seeing or knowing anything else about your truck, I'm guessing you have the factory 10 ten bolt diff front and rear, with 8.5" ring gear. The ten bolt diffs came in 28 spline and 30 spline varieties. You need to make sure you match up correct number of splines or whatever you put in there may not fit.

If you change the gears or swap the whole axle for one with limited slip be absolutely sure it's the same gear ratio as the rear diff. I had an '84 K5 years ago. The rear end, with factory 2.73 gears, blew up so I swapped the whole axle with one with 3.73 gears. I couldn't use four wheel drive with risking tearing everything apart until I swapped the front axle with a 3.73 diff also. Somebody correct me if I'm wrong, but I believe you can have a variance of up to 0.10 between the front and rear gears. For example, you can run a Dana with 4.11s in the rear and corporate with 4.10s in the front still be okay.

There are several ways to go about what you want:

1) Without swapping anything you could simply install a limited slip differential in place of that open diff. I wouldn't go with a used one because, depending on how much abuse its taken, it may have little life left to it or not work at all.

2) Find a whole axle with a locker or limited slip and swap it. As I said above, be sure the gear ratios are the same as the rear axle.

If you're willing to spend a little bit of money I would look into the Detroit True-trac limited slip differential. They're around $550 for the ten bolt diff units. I am eventually going to install True-Tracs in the front and rear on my '80 K25. They are appealing because they are completely gear driven. No clutch packs and springs, it is always fully engaged. The instant one when one wheel looses traction torque is diverted to the wheel with traction before the low traction wheel slips. But if you really not using it often, then stick with a cheaper option.


I bought a grizzly locker for my dana 60 front in my s10/offroad truck. Im excited to give it a try. Its also fully mechanical, but it unlocks on turns.
 

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A mini spool is going to be your cheapest, easiest solution. The thing about running a mini spool is you're going to have to run with 1 hub unlocked except when you are going basically straight.Backing down a boat ramp NBD going up a boat ramp NBD trying to turn that's going to be your problem.If I truly just wanted to go up and down boat ramps, drive on loose dirt or get unstuck, I'd have a mini spool in it.
 

AlexK10

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A mini spool is going to be your cheapest, easiest solution. The thing about running a mini spool is you're going to have to run with 1 hub unlocked except when you are going basically straight.Backing down a boat ramp NBD going up a boat ramp NBD trying to turn that's going to be your problem.If I truly just wanted to go up and down boat ramps, drive on loose dirt or get unstuck, I'd have a mini spool in it.

Yes, that's basically the use I will have for it, boat ramps straight up/down and getting unstuck.

When on 2x4 I always have both hubs unlocked ("free" position).

Any suggestions on quality/brand for a mini spool, or are all the steel alloys used within the same design basically equally good for my purpose?
 

Ricko1966

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I'd check midwest Motorsports for good used.If the dirt track racer selling it didn't break it, you're not going to,Its quality control, but different.
 

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If your going to spool or weld the diff do it to the rear one not the front. If you do it on the front axle then steering will be affected any time you have the hubs locked in. Auto locker, LSD or selectable locker in the front only IMHO
 

Ricko1966

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If your going to spool or weld the diff do it to the rear one not the front. If you do it on the front axle then steering will be affected any time you have the hubs locked in. Auto locker, LSD or selectable locker in the front only IMHO
Already covered. Read back a few and you don't want to run a spool frt or rear in a street car.But he's not driving with the frt hubs locked in just going straight, up and down boat ramps.Sorry I gotta go mow, and mount some tires.Ill be back in a little bit to pi$$ everybody off.Thanks for your understanding.
 

Craig Nedrow

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I bought a grizzly locker for my dana 60 front in my s10/offroad truck. Im excited to give it a try. Its also fully mechanical, but it unlocks on turns.
Hey Vince did you swap inn the Grizzly yet? just did my 14 bolt 10.5 with a Grizzly locker and like it, was getting ready to service the front, (mine is a D44, 4:10,) thinking of the same locker for it, but wanted to talk to someone with before and after experience, mainly road manners. I know the trail manners will be awesome.
 

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