Locker for a K3500 Dually

[JetBoater]

I have been considering installing a posi for maintaining 'dually' footing on slippery concrete boat ramps.

I have lost traction while pulling my buddy's boat out of the ocean with the camper on, at low tide. The issue went away with 4X4 engaged, but NOT being able to move forward with the ocean coming in behind you is not a nice feeling.

What posi would be best, and what will hold up to all the weight? I am guessing an air locker ? Experience/advise ? Should I bother?

The truck is empty during winter, and at maximum weight capacity in the spring, summer, and fall with the camper and boat.

:)

[JohnC]

I'm sure I'll get jumped all over for saying this, but, the Eaton factory G80 option is perfect for that application...

No bad manners in the winter!

They come up on E-bay frequently for around $200. Search for "10.5 locker"

[crashz]

My concern would be the initial slip of the wheels then the grab of the locker. With a heavy truck, camper and boat in tow, I think the Gov-Lock might fail. The shock of it locking up could break the the locker or even an axle shaft.

If you are going to the trouble of tearing into the rear end (the 14 bolt FF's are one of the easier axles to set-up), pop for the extra control of the Eaton E-Locker. Flip of a switch and the axles are locked. No slip, no bang, and less of a chance of breaking an axle or anything else with proper operation. Lock it in as you back into the water and unlock it before you make any turns.

John is right about winter operations though. The Gov Lock works well because its only working when your stuck. A locked rear axle on slippery surfaces make a moving truck slide sideways very easily. The Gov is less likely to do that.

[john8662]

When does a G80 ever work?

:rolleyes:

[JetBoater]

The Eaton E-Locker sounds like the right unit for my application.

My concern was breaking something if I went to a true locker, or chewing through clutch packs on limited slip type lockers. My extra weight is the issue of concern.

Thanks gents! :)

[crashz]

When does a G80 ever work?

:rolleyes:


:) Confirmed that mine works just a few weeks ago when I got stuck!


Mine, (and keep in mind that this is a half ton) engages and works properly but bangs really hard when the governor locks the clutches. So bad that it feels like someone hitting the truck with a sledge hammer. I know someday that I'll pulll out of my driveway (this happens frequently) a tire will slip in the sand, and BOOM! ....... 10 bolt differential pieces everywhere!

[DmaxMaverick]

My concern would be the initial slip of the wheels then the grab of the locker. With a heavy truck, camper and boat in tow, I think the Gov-Lock might fail. The shock of it locking up could break the the locker or even an axle shaft.

If you are going to the trouble of tearing into the rear end (the 14 bolt FF's are one of the easier axles to set-up), pop for the extra control of the Eaton E-Locker. Flip of a switch and the axles are locked. No slip, no bang, and less of a chance of breaking an axle or anything else with proper operation. Lock it in as you back into the water and unlock it before you make any turns.

John is right about winter operations though. The Gov Lock works well because its only working when your stuck. A locked rear axle on slippery surfaces make a moving truck slide sideways very easily. The Gov is less likely to do that.

That's how the Gov-Loc works, any time and every time it engages. If it were so week it fails under these conditions, there would be none left working, and the design abandoned. They do fail on occasion, but so does everything else. The Gov-Loc doesn't fail any more often than any other component considered "reliable".

Considering cost, simplicity and convenience, the Gov-Loc is the best option. Limited slip is an obsolete thing of the past. They have their place, but don't perform well at all under heavy load. Air lockers and the E-Locker are nice, but expensive. They can also be less convenient. By the time you decide it's time to lock in, it may be too late already (been there...done that). The Gov-Loc is idiot proof. They work. They just plain work. Every time.

[JohnC]

Yup, I've had for of them and never a lick of trouble. Come to think of it, I think the Yukon has one too. Make that 5.

If you break one, I'm guessing you're pretty aggressive with the go pedal.

[6.5TD Burb]

One bad thing about E-lockers are they are not rebuildable, so if it comes time and it will eventually to rebuild you'll have to buy a new unit. Well, this was the case when they first came out, I don't know about now.


:) Confirmed that mine works just a few weeks ago when I got stuck!


Mine, (and keep in mind that this is a half ton) engages and works properly but bangs really hard when the governor locks the clutches. So bad that it feels like someone hitting the truck with a sledge hammer. I know someday that I'll pulll out of my driveway (this happens frequently) a tire will slip in the sand, and BOOM! ....... 10 bolt differential pieces everywhere!

That sounds more like a Detroit?

[JetBoater]

OK... I'll give the Gov-Loc a search and see if I can find one. The cost-less option is always more attractive anyway.

Thanks for the reassurance!

[john8662]

I've had success with the 10 bolt version. The one used in the 14bolt FF, I've had two duds with. My K2500 Suburban with the 14FF has the G80 option and it only one-tire fires (135k miles on assembly). The K3500 Dually also has one, it'll two-tire fire and not four tire fire (177k miles on assembly). Sucks! So, I question the 14FF 10.5" G80 unit.

[DmaxMaverick]

First off, "G80" only denotes the GM RPO code for rear axle traction assist. The code was the same before lockers were an option, and limited slip was the only option. About 1995 was the year Gov-Loc replaced L/S. Even back when L/S was the only option, GM labeled it "locking rear differential". So, terminology is really vague in this area.

To keep it simple, almost all Gov-Loc problems can be attributed to poor maintenance practice. The components are plenty strong, but require regular (proper) service to last. Most issues are caused by the wrong, or poor quality lube. If engagement is harsh (bangs in, all the time), the clutch is probably shot. The clutch doesn't aid in engagement, but is only there to "soften" engagement, like a synchro in a tranny. Engagement is a solid mechanical connection, once complete. Many times, a drain/fill with a high(er) quality lube is all that is needed to cure harsh engagement. Synthetic lube is recommended, and is required for most applications.

[crashz]

Thanks DMax!

That could be the problem with mine. I service it approximately every 30K miles, but its due now and to be honest I think I put in a cheaper brand of synthetic (I believe its valvoline 75w-140 right now).

I'll clean, inspect & change with RP and see how it goes. I'll also retract my satement of the G80. In all honesty it does work. Its gotten me out of a few slippery spots and with 120K, still works as it did when new. I don't drive it hard, but I do some light snow plowing and it sees some off-road and dirt roads from time to time. I also live on a unique hill, hence my driveway tale.

[DmaxMaverick]

Valvoline synthetic lubes are pretty good, by comparison (no better/worse than RP, IMO). Sounds like it could be more of the 75-140 during very cold temps lately. The stuff would be like bunker oil at that temp. Perhaps it wasn't warmed up?

Unless you are doing a lot of real heavy towing during the winter, I'd suggest using 75-90 lube. I don't think 140 would ever be beneficial in your climate with that truck, year round. A 1/2 ton will see only so much load. 75-90 synthetic should be more than adequate (and might improve economy a bit).

I use Amsoil 75-140 Severe Gear, but most of my really heavy towing is during the summer in CA. Hot and heavy! I'd use 75-90, otherwise.

[JetBoater]

I took some pics of my carrier during my last service, and wonder if I do have an old gov-loc? Could someone advise?

If this is a gov-loc, it must be the older style (truck is 1993) and worn out.

)http://i97.photobucket.com/albums/l240/jetboater/Trucks/14%20Bolt%20Carrier/IMG_1256.jpg

A couple more picts here:
http://s97.photobucket.com/albums/l240/jetboater/Trucks/14%20Bolt%20Carrier/

Thanks, Mike

[JohnC]

I took some pics of my carrier during my last service, and wonder if I do have an old gov-loc?


It's been a long time since I looked at a 10.5, but I believe that's it. On the open carrier you can see the spider gears.

Jack up the rear axle and have someone help you spin the two tires in opposite directions. If it's working, it'll lock up briefly if you can get the relative speed of the two wheels to reach 100 RPM (pretty easy to do.)

What kind of lube did you put in it?

[JetBoater]

Hmm, you may be onto something John.... maybe I need an additive for this style gov-loc?

I used GM rear axle lubricant, whatever that is. It comes in 1 liter bottles here in Canada.

I asked a friend what carrier i had at that time, and he told me it was open. It didn't look like a typical open carrier, but I took his word for it. I did not see any spider gears. I was also looking for 4 shafts that hold those gears, but only saw 3.

I guess I could acquire some posi-additive and see what happens; or would you recommend taking out the unit and inspecting the fiber discs first?

[JohnC]

Do not use any limited slip additive. IIRC, it was designed for 80W90 GL5.

Could be it needs new discs at this point. You're getting beyond my knowledge zone. How many miles?

One time I got stuck with the '93. I was cursing the locker. Maybe not the smartest thing to do, but I put it in lo (5 speed), let the clutch out at idle and got out and walked around the truck. Both rear wheels were turning (forward) about 1 mph...

[JetBoater]

My truck has 184,000 kms (114,000 miles).

This dually was worked hard by previous owners. This is its 3rd engine. I added the P400 power plant at 175,000 kms.

I assume the gov-loc is completely worn out. I will jack up the back-end when the rain stops here... and spin the wheels to verify action.;)

[JetBoater]

I jacked up the back wheels and spun the tires. The tires on the other side turned in the opposite direction.

I have used power lock and true-trac lockers in previous trucks, and those lockers always engaged so that the wheels spun in the same direction.

I had a friend hold the tires on one side while I tried spinning the other side, and they definitely held firm. Steve is a good 275 lb man who held his side solid. I could not rotate the tires on my side at all. I guess this little test confirms I have some amount of posi-traction.

If anyone has a newer style gov-loc, detroit, or other similar for sale, PM me. I have 4.10 ratio.
Thanks.

[DmaxMaverick]

John's correct. Do not use ANY additive. That stuff was for older limited slip diffs, which you shouldn't have (and don't, according to your test). For the older trucks (~1995), GM 85w-90 GL-5 was the recommended lube. Problems with some later on found the use of synthetic 90 GL-5 cured the issues.

The Gov-Loc is open (and should spin freely) until locked, exactly like an open diff, until it locks. With both tires off the ground, you should be able to spin one side by hand (or foot) fast enough to engage the lock. The wheel should lock and jerk at this point. The 100 RPM differential wheel speed may sound like a lot, but it isn't, and with both wheels up, it only takes 50 RPM's on one side to get it to lock (50 RPM's forward on one side + 50 RPM's reverse on the other side = 100 RPM differential). I can't tell anything by looking at the pic you posted, and I couldn't get the larger images to load at your picture album site (tiny thumbnails only??), so I can't tell what you have. Try posting the larger images in this thread, like you did the first one.

[JohnC]

I jacked up the back wheels and spun the tires. The tires on the other side turned in the opposite direction.

This is normal operation.


I have used power lock and true-trac lockers in previous trucks, and those lockers always engaged so that the wheels spun in the same direction.
Right, but the gov-loc is unlocked normally.


I had a friend hold the tires on one side while I tried spinning the other side, and they definitely held firm.
I assume you had it in park or in gear if it is a standard. Again, this is normal. If one wheel can't turn and the driveshaft can't turn then the other wheel won't turn either.

Have Steve spin his wheel backwards while you spin yours forwards. When it grabs you'll feel a jerk as both wheels try to turn the same way. (They can't if the driveshaft can't turn, but they'll try.)

Do you have the RPO codes in the glove box? Does it list G80?

[JetBoater]

It was in park... thanks, makes sense. I will give it another spin after work today in neutral. The glove box did not list G80 code that could see, just cargo weight capacity.

I won't use additive. Sounds like I have the right gear oil, GM 85w-90 GL-5. Here are a few more pics.

http://i97.photobucket.com/albums/l240/jetboater/Trucks/14%20Bolt%20Carrier/IMG_1255.jpg

http://i97.photobucket.com/albums/l240/jetboater/Trucks/14%20Bolt%20Carrier/IMG_1257.jpg

I found this diagram on the web also, and assume it depicts my carrier?
http://i97.photobucket.com/albums/l240/jetboater/Trucks/14%20Bolt%20Carrier/untitled-1.jpg

Sorry if the pics weren't the greatest.

[JetBoater]

pics are not showing up properly, I downsized to 800 x 600 but they are huge... sorry, will try to fix.

[JetBoater]

Smaller pics:
http://i97.photobucket.com/albums/l240/jetboater/Trucks/14%20Bolt%20Carrier/410Dif.jpg

http://i97.photobucket.com/albums/l240/jetboater/Trucks/14%20Bolt%20Carrier/410Dif1.jpg

[JetBoater]

Ok, good and bad news.

Good news: I found the G80 number on another decal under the glovebox junk. This would indicate I have a gov-loc.

Bad news: I spun the tires and had my neighbor jam the opposite wheel when it got up to speed, and no clunk. We did this 3 times and felt the wheels slow down, but that was it.

What now? Rebuild or replace? :confused: Cheaper to rebuild it I guess....
JohnC / DmaxMaverick, I do appreciate you workin with me on this ;)

[JohnC]

Just spin them in opposite directions as fast as you can. If nothing happens, then it isn't working. If it grabs, one wheel will try to switch directions.

Maybe time for new clutch packs.

[crashz]

Well, at least you have an easy axle to work on. The 14 bolt is real easy to set up, especially when ou don't need to touch the pinion gear.