G80 On The Front?

GUSTHEPIANO · October 17, 2009

I've just done an axle oil change on my 2002 Suburban 1500 4x4 LT. I have the build sheet for it, it stated "Locking Rear Differential $252" however, when I drained the oil it was obvious the rear axle was a bog standard rear axle, which made me think the dealer had "Bumped" the original owner for $252, but when I dropped the skid pan, the front axle was I believe to be, according to the glove box info' a G80. My question is: Is this normal, to fit a locker/limited slip to the front axle?

Keep Rockin'

Gus in the UK.

PS. Great Site.

Keep Rockin'

Gus in the UK.

PS. Great Site.

grampadirt · October 17, 2009

The G80 will be in the rear,bad idea to have a locking front axle

dlstewart01 · October 17, 2009

There is not a locking diff made for the front. You would not be able to steer it, and trying to would damage components.

If it is in the glove box you have a locker in the rear.

fcknmaw · October 17, 2009

You can put a selectable locker in the front for wheeling. Such as an e-locker or air locker, but I doubt you have a G80 up front. My 03' Jeep TJ had an e-locker up front.

outhouse · October 18, 2009

lockin front diff's are common and if you were to have one i would think a G80 would be better then a true locker [always in]

depends where you live and how much you offroad

the electric lockers are great because when your on a sideways ice or slippery snow sheet the rear and front will drift hard locked.

i would check the 4/4 forums and do some asking around because i know its been done many times over.

GUSTHEPIANO · October 18, 2009

There is not a locking diff made for the front. You would not be able to steer it, and trying to would damage components.

If it is in the glove box you have a locker in the rear.

I looked in my 2002 Tahoe/Suburban owners’ manual to see what oils to use in the axles. For the Front Axle: It reads: SAE 80W-90 Axle oil (GM Part No 1052271). When I checked on the web what GM 1052271 oil is used for, this was the answer:

If you have a locking differential (G80), you need to use SAE 80W-90 GL5 Gear Lubricant, GM P/N 1052271. Do not use limited slip additive.

It would therefore appear that the 2002 4x4 Suburbans with a G80 limited/locking diff’ are all fitted to the front axles, why else does the manual instruction recommend the use of GM 1052271 in the front axle?

The Recommended oil for the rear axle is SAE 75W-90 synthetic (GM Part 12378261)

Which is for use in the normal standard axle.

I would still like to know if this is standard practise and was wondering if there is a GM Chevy Suburban department I could contact at GM?

I’d like to thank everybody for their comment. Cheers.

gave20 · October 18, 2009

Well the web is wrong, 80-90 up front 75-90 in the rear or Mobil 1 75-90 all the way around.

KMGZ400 · October 18, 2009

no, GM does not make a locking front diff!! dlstewart is right, i would completley screw up your handling if it locked on the road. it probably has a locking REAR diff.

anyway, go find some rocks and find out if you have a locking front diff, thats the only way to find out

Z45 · October 18, 2009

As has been said, G80 only refers to the rear axle.

NO GM SUV's come with a locking or limited slip front differential. Its not an Regular Production Option.

fyi

LOCKING DIFFERENTIAL LUBRICANT (SERVICE INFORMATION)

SUBJECT: LOCKING DIFFERENTIAL (G80) LUBRICANT - (SERVICE INFORMATION)

VEHICLES AFFECTED: ALL LIGHT TRUCKS EQUIPPED WITH G80 REAR AXLE ALL YEARS

Some light duty trucks equipped with locking rear axles (G80) may exhibit rear axle chatter, especially when turning a corner from a stop.

This condition of alternate engagement and disengagement of clutches in differential assembly is usually caused by contaminated axle lubricant.

To correct this condition, drain and refill the rear axle. The use of any additive in locking rear axles (G80) is not recommended. Rear axle additives are designed for use in limited slip differentials which are normally installed in cars. All light duty trucks equipped with RPO G80 make use of a locking differential and the use of additives will delay the engagement of the locking mechanism and may decrease axle life.

This bulletin is being issued to inform dealers about the compatibility and usage of the new Fuel Efficient SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (In Canada use P/N 10953455), with current axles, and with the non-synthetic axle lubricant, GM P/N 1052271 (In Canada use P/N 10950849), for the rear axles on the above light-duty trucks.

Testing has shown that the new synthetic lubricant will chemically attack the Room Temperature Vulcanizing (RTV) sealant. Use only the non-synthetic lubricant, P/N 1052271, in axles using RTV sealant (See 9.5 and 10.5 information below).

American Axle and Manufacturing (A.A.M.) has approved the use of the new Fuel Efficient SAE 75W-90 synthetic axle lubricant for rear axles with the following restrictions:

All 8.6 inch axles are compatible as originally built.

9.5 inch axles on vehicles built prior to mid-February 1998 are NOT compatible because RTV sealant is used on the cover pans. On vehicles built after mid-February 1998 and equipped with 9.5 inch rear axles, synthetic lubricant, P/N 12378261, can be used because the RTV was replaced with a gasket. Other mid-February changes to the 9.5 inch rear axles include a new cover pan and cover pan fasteners common to other axles.

Important

The new cover pan is not retro-fittable to the housing of 9.5 inch axles on vehicles built prior to mid-February 1998. A new retrofit kit is available that will enable the use of synthetic lubricant for vehicles built after mid-February, 1998.

All 10.5 inch axles prior to March 3, 1999 are compatible if the axle shaft hub seal (RTV) is replaced with P/N 327739 gasket when changing to synthetic lubricant.

As a product improvement, this new lubricant has been released into 1999 current production C/K vehicles built after the above VIN breakpoints (Except HD3500 models which use 75W-140 synthetic lubricant, P/N 12346140).

It is recommended that synthetic lubricant be used when changing rear axle lubricant for the following reasons:

Potential fuel economy

Lower operating temperature under severe usage conditions

Important

You do not need to wash/rinse any non-synthetic lubricant from the axle cavity when changing over to a synthetic lubricant. However, you should remove debris from the magnet and the bottom of the axle cavity whenever the axle fluid is changed.

On light-duty trucks equipped with locking differentials, do NOT use a limited-slip additive.

GUSTHEPIANO · October 26, 2009

no, GM does not make a locking front diff!! dlstewart is right, i would completley screw up your handling if it locked on the road. it probably has a locking REAR diff.

anyway, go find some rocks and find out if you have a locking front diff, thats the only way to find out

First off, let me thank you all for all your comments. You were all right the G80 locking diff’ is fitted to the rear. I’ll have to explain. When I performed the oil change I had jacked the whole vehicle off the ground, I then spun the rear passenger wheel and the drivers side wheel turned in the opposite direction, and therefore assumed the axle was a conventional one…which of course it is until one wheel spins 100 rpm faster than the other, you will have to excuse me for having a “senior moment”.

My drive has quite a slope, so yesterday I placed a couple of 8x4 plywood boards on the drive and greased them up and placed them in front of the passenger side rear wheel, and as you would expect the wheel on the grease started to loose traction and the drivers rear cut in as smooth as silk, pulled off the drive no problem.

I do hope this has not coursed an international incident or damaged Anglo-American relations.

PS. Know what removes burnt tyre & grease marks off block paving?

Keep Rocking Gus

dlstewart01 · October 26, 2009

no, GM does not make a locking front diff!! dlstewart is right, i would completley screw up your handling if it locked on the road. it probably has a locking REAR diff.

anyway, go find some rocks and find out if you have a locking front diff, thats the only way to find out

First off, let me thank you all for all your comments. You were all right the G80 locking diff’ is fitted to the rear. I’ll have to explain. When I performed the oil change I had jacked the whole vehicle off the ground, I then spun the rear passenger wheel and the drivers side wheel turned in the opposite direction, and therefore assumed the axle was a conventional one…which of course it is until one wheel spins 100 rpm faster than the other, you will have to excuse me for having a “senior moment”.

My drive has quite a slope, so yesterday I placed a couple of 8x4 plywood boards on the drive and greased them up and placed them in front of the passenger side rear wheel, and as you would expect the wheel on the grease started to loose traction and the drivers rear cut in as smooth as silk, pulled off the drive no problem.

I do hope this has not coursed an international incident or damaged Anglo-American relations.

PS. Know what removes burnt tyre & grease marks off block paving?

Keep Rocking Gus

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