old style locking hubs

[57taskforce]

Those are too cool, love the 4x cast into the dial. Nice find Pete.

[DeadheadNM]

I thought those Phillips head screws were an odd choice.

[special-K]

Can you imagine how those 'screws' would get pack with mud? And the slots aren't that deep. You would definitely want to keep a little wire brush tethered to that tool. And that tool? Better know where that is before deciding to hit the slop

I have one set of hubs that are, what I think, early automatic hubs. They are Dualmatic or Selectro. No knob, just a shiny stainless cover. It appears to be just press-fit on. I'll have to dig those out for pictures. I have never attempted to disassemble one

[Ol Blue K20]

Originally Posted by special-K

Can you imagine how those 'screws' would get pack with mud? And the slots aren't that deep. You would definitely want to keep a little wire brush tethered to that tool. And that tool? Better know where that is before deciding to hit the slop

I have one set of hubs that are, what I think, early automatic hubs. They are Dualmatic or Selectro. No knob, just a shiny stainless cover. It appears to be just press-fit on. I'll have to dig those out for pictures. I have never attempted to disassemble one

I never saw an automatic hub. Except the explode o magic used by GM in the eighties.

[1976gmc20]

Originally Posted by Ol Blue K20

I never saw an automatic hub. Except the explode o magic used by GM in the eighties.

Our 1991 Suburban (square body) had mechanical automatic hubs when we got it. They didn't work once up in the mountains so as soon as we got home I had them swapped out for a set of manual Warn hubs. Actually, I still have those factory hubs sitting out in the garage because I intended to keep the Warn hubs if I ever sold it, but when the time came I just said the hell with it. I'm not planning to ever get another half ton 4x4 anyway.

[special-K]

I never had a problem with those GM automatic hubs. It's all about technique. I did switch mine out, too, just because I wanted as heavy duty and simple as possible. I was also pushing their limit with 35/12.50s

[1976gmc20]

Originally Posted by special-K

I never had a problem with those GM automatic hubs. It's all about technique. I did switch mine out, too, just because I wanted as heavy duty and simple as possible. I was also pushing their limit with 35/12.50s

I dunno about technique. All I know is that I was trying to back our camper trailer up a little grassy slope into a cove of the timber for a campsite. I put it in low range and the rear wheels spun. Pulled forward a few times and tried again and finally it worked.

If anyone wants those old hubs, they can have them

[special-K]

The technique I used was let it spin lazily until you feel them engage. Not nail it until you feel them grenade. Same with the Gov-Loc. I never blew one of those either using the same technique. It's the trade-off for the convenience. I never looked at walking up to my front wheels and turning knobs as a hard thing to do anyway. I'm a manual kind of guy

[1976gmc20]

Originally Posted by special-K

The technique I used was let it spin lazily until you feel them engage. Not nail it until you feel them grenade. Same with the Gov-Loc. I never blew one of those either using the same technique. It's the trade-off for the convenience. I never looked at walking up to my front wheels and turning knobs as a hard thing to do anyway. I'm a manual kind of guy

The hubs didn't blow up, they just didn't engage until after I pulled forward and tried to back up again several times. Fortunately we weren't stuck - just trying to do something a little bit difficult. It's not "convenient" when your 4wd doesn't work when you need it.

The last ten years or so we had that Suburban, I almost never unlocked the hubs as the only time we drove it was when the roads were really bad, or else to just go charge the battery and I wanted to lube up the front end anyway.

My 89 K1500 front axles are permanently locked together as it is a "ranch" truck. I'm still waiting to see how the electric/gear actuator holds up on the 2016 long term. It has the manual TC lever but still the "thing" between the front axles. It also has the limited slip rear which I really like but I don't know if it is as vulnerable as the old ones? But I drive like the grandpa that I am

[LONGHAIR]

Originally Posted by 1976gmc20

The hubs didn't blow up, they just didn't engage until after I pulled forward and tried to back up again several times. Fortunately we weren't stuck - just trying to do something a little bit difficult. It's not "convenient" when your 4wd doesn't work when you need it.



It also has the limited slip rear which I really like but I don't know if it is as vulnerable as the old ones? But I drive like the grandpa that I am

I worked in a 4x4 shop back in the 80s up to '92 and I replaced dozens, if not hundreds at that time. Many of them would either not lock at all, lock only moving forward, or not unlock. I did see a few actually grenaded, but they were on modified trucks with way too big of a tire for them.
The newer trucks still use the same code number (G80) as they did back then, but I don't know if they are the same anymore? They had a bad reputation too. I replaced a ton of them too. Most of them just threw up the little gears/springs of the governor. Not exactly what you want roaming around in your gear lube and it deactivates it as far as usefullness. I have seen them explode badly enough to crack the whole housing.
These were again usually done by people abusing them. Bigger tires or extensive off roading were mostly to blame. Crazy spinning on a concrete boat ramp was the killer of the worst I ever personally took apart.
I hope they are ok now a days because I have one in my 20 Colorado.

[1976gmc20]

I hope they are ok now a days because I have one in my 20 Colorado.

Mine is a huge 2500 so you'd think it would be fairly stout.

We have a deep water bar at the bottom of our turn-around/parking area where it necks into the driveway, so all the runoff doesn't just run down the drive. It is nice to be able to get going again after slowing nearly to a stop when it is a little slippery without having to grab 4wd just to go another hundred feet.

Got spoiled with the Jeep because it has a mechanical full time 4wd with no hubs. Just got it back from the shop yesterday after three months. He is slow but I trust him.

[57taskforce]

Originally Posted by 1976gmc20

Mine is a huge 2500 so you'd think it would be fairly stout.

We have a deep water bar at the bottom of our turn-around/parking area where it necks into the driveway, so all the runoff doesn't just run down the drive. It is nice to be able to get going again after slowing nearly to a stop when it is a little slippery without having to grab 4wd just to go another hundred feet.

Got spoiled with the Jeep because it has a mechanical full time 4wd with no hubs. Just got it back from the shop yesterday after three months. He is slow but I trust him.

Fortunately your 2500 if a 6.0 has the same old tried and true 10.5 14 bolt (note, not duramax or dually, those are an 11.5” and not the same) that we all love and regard so much, just with fancy rear disks, Dana 70 spec axle tubes, metric lug studs and spacing, and a slightly wider wms. Internally the newer 10.5” 14 bolts are 95% identical. Unfortunately it’s got the same old gov-bomb G80 that they have had for a long time, which aren’t really known for being really stout. Don’t abuse it too bad and you’ll likely never have an issue. My 18 Sierra 2500 company truck weighs north of 12K and is ALWAYS in the sand or the mud depending on the time of year. 82,000 miles later with slightly oversize BFG and Toyo mud tires and it still works perfect. It’s when you go into it full throttle and one tire grabs unexpectedly, or you hammer it with one tire spinning hard that the governor blows up like longhair mentioned. They are quite handy when they work right.

[1976gmc20]

Originally Posted by 57taskforce

Fortunately your 2500 if a 6.0 has the same old tried and true 10.5 14 bolt (note, not duramax or dually, those are an 11.5” and not the same) that we all love and regard so much, just with fancy rear disks, Dana 70 spec axle tubes, metric lug studs and spacing, and a slightly wider wms. Internally the newer 10.5” 14 bolts are 95% identical. Unfortunately it’s got the same old gov-bomb G80 that they have had for a long time, which aren’t really known for being really stout. Don’t abuse it too bad and you’ll likely never have an issue. My 18 Sierra 2500 company truck weighs north of 12K and is ALWAYS in the sand or the mud depending on the time of year. 82,000 miles later with slightly oversize BFG and Toyo mud tires and it still works perfect. It’s when you go into it full throttle and one tire grabs unexpectedly, or you hammer it with one tire spinning hard that the governor blows up like longhair mentioned. They are quite handy when they work right.

Thanks! I don't think I ever full throttle anything.

[LONGHAIR]

Even back in the 80s-90s when those Gov-locs had such a bad rep, the bigger ones were better. I don't really know why? They still had the same stupid little spinning governor bits as the 1/2 ton units.
I've been out of the game so long, I haven't even seen inside of one of the newer ones.
The G-80 name is just an option code during manufacturing. It means different things for different years.

[1976gmc20]

Originally Posted by LONGHAIR

Even back in the 80s-90s when those Gov-locs had such a bad rep, the bigger ones were better. I don't really know why? They still had the same stupid little spinning governor bits as the 1/2 ton units.
I've been out of the game so long, I haven't even seen inside of one of the newer ones.
The G-80 name is just an option code during manufacturing. It means different things for different years.

The entire rear axle under my 2016 looks massive! I have more truck than I really need right now but I plan to keep it a long time and I know it can do just about anything I ever want it to do.

There is also the probability that folks who bought a 2500/3500 HD got them for work and didn't hot rod them like the half tons.