lockers?

Well...as far as factory lockers go...Look in the glove box. There should be a sticker in there with the factory options for the truck listed. Look for a code that says "G80". The G80 is the Eaton locker offered as a factory installed option in Chevys. I don't know if Chevy offered a factory locking diff for the front axle, but it's possible.

I *had* one... It failed and took out my rear axle--requiring a rebuild. Not to say that it's total crap, but I've never heard a single good comment on the G80. It's an automatic locking differential, meaning that when it senses wheel slip exceeding a certain RPM relative to the other wheel, it'll lock. The problem, as it was described to me, was the quick and violent nature by which it locks, which can lead to failure. I can't say with 100% certainty that this is true, but I do know that the diff seemed OK up through the winter of 2004-2005, and then the unit failed not long after. By coincidence (or not) we hard a pretty good freeze here in Atlanta and I was out driving in it. During that driving, the back wheels were slipping quite a bit, and the diff was locking and unlocking during all that. BTW, the fact that I had no control over the locking and unlocking made driving...er...interesting. There was no predicting how it would react.

When I had the axle rebuilt, I specified an open (non-locking) differential to be installed. To me, the ultimate solution is a selectable locker, where you can either run open or fully locked.

Just my $.02...

~jp

mudm> how do i know if i have lockers in my 84 1/2ton suburban. thank you in

Well there never was a factory "locker" offered in that vehicle ever. There was a limited slip offered under a G80 as mentioned above (also called the gov loc) but it was not a locker despite its name which is very misleading. It uses a govenor controlled clutch pack thats "locking" abilites are limited by clutch capacity and function. It also is disabled at road speeds above about 20MPH. It is know for cluncky/jerky operation at times and the one used in 10 bolt axles are the least sturdy of them all because the smaller ring gear size limits their size. GM has be offering a G81 last few years in HD which uses a better Eaton LSD that is more predictable and durable.

----------------- TheSnoMan.com

True...the G80 uses clutches, which would technically put it closer to a LSD in operation.

I know mine was fine until it got worked hard that one winter. When I replace the axle (again) I will be going with something a bit more substantial back there. More than likely a 14-bolt, but possibly something else...

~jp

SnoMan wrote:

I would suggest a 14 bolt 9.5 semi floater. It is often overlooked and it is a very stout axle. It usually has 6 lug hubs though it can have either. Even the gov loc in it is a lot sturdier and the housing and the axles are a lot stronger than a 10 bolt (it can safely carry about

3 tons vs maybe 2 tons on 10 bolt) yet it weighs about 75 pound less than a 14 bolt full floater and has better ground clearance too. It is about the equal of a D60. The 10.5 FF is rated at about 4 tons capacity.

----------------- TheSnoMan.com

What numbers in the glove box do you use to figure out what rear is in our

3500 dually 6.5TD I know it is a 14 bolt. When I had it jacked up I turned the wheels and they rotated in opposite directions, but a few days ago we parked on a hill and the right side was in mud. When I pulled out it started to spin for just a second and then it locked in and pulled out with the side that was on the road. I think it must be a locker because I never had a limited slip that could move a 10,000 lb. (truck loaded at the time) and with 12,000lb on a trailer... truck had with one wheel in mud and one on dry.

It will say G80. GM never put a true locker in those trucks EVER. (around 2005 there was a G81 too with was a different kind of Eaton LSD (not a GovLoc like G80 is) When you get to the bigger axles like the 14 bolt FF, it has a pretty good posi action to it because there is room for a bigger diameter carrier and clutch pack to limit slippage.

----------------- TheSnoMan.com

What type of LS unit is in the new 2500's?

Al

Either a old classic G80 GovLoc LSD or a G81 Eaton HD LSD on some models that is not a GovLoc design and has smoother more predictable responce

----------------- TheSnoMan.com

So they don't use a limited slip like Dodge with all the small gears and no clutches? Is AAM making GM axles?

Al

To clear up the confusion about the G80; 2004 Colorado, 5 cyl, Z71

The G80 is a locking differential. When one wheel spins 100 RPM faster than the other one, the governor locks the diff solid, no limited slip !!! The clutches only serve to make the process smooth. It all happens in a split second and, in loose gravel, I never know that it is locked unless I look at the tracks I leave; gravel spun out on both sides. The only way the diff can be destroyed is, when you step on it hard on a slippery surface and then hit a dry patch with one wheel.

I am very happy with that axle and the operation of the differential. Never had any problems with handling in any road condition.

John

Well first Dodge does not make one, it is from a aftermarket supplier and GM does use one like it in some specailized models but not in 2500 ot 3500 P/U's at this time. AAM has been making axles for GM for a long time and most notabley the 10.5 inch 14 bolt full floater well known for its sturdy qualities. Now all their axles are AAM and most of Dodges are now too (all 2500 and 3500 truck use them front and rear and 1500 P/U's use then in front and some LD SUV's use them front and rear and the front axle in HD P/U's is based on the same ring and pinion that GM uses in its IFS in HD trucks, the 9.25 and gears for it will fit in Dodge front axle) Funny thing is that ALL Dodges with 4x4 use no front axle disconnect be it IFS or solid (saves Dodge a few bucks) which means EVERY 4x4 they make will use more fuel than it should (about 1 MPG on HD models and 2 or 3 MPG less on LD models) because it will always be spinning the front ring/ pinion and drive shaft too even in 2wd. Dodge does not tell you that though. Better yet when Dodge went to a IFS front axle rather than using the proven 7.5 and 8.25 front axle with a disconnect, Dodge used a AAM 8.0 that was designed for a rear IFS with no disconnect in it for a front drive axle (and people wonder why I am hard on Dodge 4x4's sometimes) Dodge uses the same 11.5 AAM rear axle now behind CTD that GM does behind

8.1 and Dmax. In their HD P/U's with a hemi they use a 10.5 AAM but it is not the same axle as GM as it costs less to make and none of the parts interchange with GM 10.5. (GM iuses a straddle mounted 3 bearing pinion design on their 10.5 axle while Dodge uses a 2 bearing pinion design axle)

----------------- TheSnoMan.com

Again no it is not!!! It used clutches and it is limited by clutch capacity as there is NO mechanical "solid" lock like there is in a true locker. (it is not your fault that you believe it is a locker because the name for it is VERY misleading but believeing does not change the facts) It can slip with torque capacity is exceeded which is not hard to do with a 10 bolt and big tires and it is not a sturdy unit either in 10 bolt axles. Also as stated before tha same govenor prevents its operation completely above about 20 MPH. True LSD's and lockers have no spoed limit.

----------------- TheSnoMan.com

My 2004 CTD has one of those geared LS units and so does my 2002 Z28. Both came in them from the factory.

Al

Snowman, get your facts straight. I have the factory service manual and have taken a close look at the differential and, it is a locking differential PERIOD

John

Your Z28 might but it is not likely that the CTD does. If it does, it is the first I have heard of it. a 2004 should have a 11.5 AAM and there was not (to my knowledge) a gear type LSD availible for it when truck was built. The Camaro seires axle would of had a aftermarket source for detriot to use though because the axle design used has been around for a long time while the AAM first saw the light of day in

2001 GM trucks.

----------------- TheSnoMan.com

On Sat, 13 Jan 2007 11:39:06 GMT, John wrote:

You are pretty thick on this. IT IS NOT A LOCKER!!!! Lockers DO NOT USE FRICTION CLUTCHES. LSD's do. (this is one of the reasons that call them LSD's because the clutches have limited torque capacity) The GovLoc may have a higher point before clutches yeild than most LSD's but it is still a modified LSD anyway you cut it. You need to look at how lockers are designed and built because they have no friction clutches in them to "lock" them. You can beleive what you want but it does not change the fact that it a LSD carrier that is mislabeled as a locker for sales hype and people like you buy it hook line and sinker. The 8.5/8.6, 9.5 and 11.5 all use the same basic design carrier with 2 spiders gears. The 8.5 and 9.5 have 3 friction plates (with 9.5 being bigger in diamete) the 11.5 has 4 friction clutches (also bigger in diameter). The 10.5 is unique in that it has a 3 spider gear design in a splitable carrier and it too has 4 friction clutch plates and all of them act on one differentail side gear. It should all be noted that one reason the 10.5 is sought after with a OPEN diff for serious off road is because it has a 4 spider gear carrier that has a a drop in detriot locker replacement for it. You simple split carrier remove spiders and install the locker in its place. It is the only rear axle carrier in production today in SUV's that is deemed strong enough for a locker. Others require a carrier replacement. If you have a GovLoc you will have to trash the whole carrier and get a open carrier to convert it to a locker. Serious off roader does not use GovLoc for long because they are not very reliable in some operations and the smaller ones have lomited torque capacity and can be toasted in very short order when that capacity is exceeded.

----------------- TheSnoMan.com

I was under the impression that it was established a long time ago that you knew absolutly nothing about dodge truck's and even less about Cummins diesel's. Now here you are disputing what a man say's is in the car and truck that he owns. If BS was music you'd be a friggin' symphony. Give it a rest will ya

The 2002 Z28 could have one of three LSD's. A SLP Installed Torsen, a Factory Installed Eaton Posi traction, or a G80 Gov-lock. Charles

Snowman, you must be about 5 feet tall; it takes a big man to admit when he is wrong.

The clutches provide limited slip action until one wheel spins 100 RPM faster than the other at which time the governor causes the cam-plate out of it's detent position. The cam-plate has humps that ride up on humps on the cam side-gear and force the differentil side-gears against the differential carrier, locking the axle shafts to the carrier. The clutches have no further part in the operation.

You do have some good information at times Snowman but, you also seem to be living in the past, not current with the latest technology.

John