Front diff pukeing fluid from vent; synthetic lube

[Dave in Mpls]

Hey, all

 

This becomes a two-part question, so bear with me!!

 

The front differential pukes fluid after driving in 4WD. I believe I have found the source as the valve on the vent tube (leaks down the inside left wheel well). Is this a prevalent problem, and any ideas on a fix (replace tube, etc)?

 

I am aware of TSB 99-04-21-003C to make the switch to synthetic in the front diff to help prevent damage to the Autotrak transfer case in cold climates. Seems I recall reading that making the switch to synthetic requires changing the vent tube or plastic connector due to material incompatability issues, but am unable to locate any TSB on this subject (99-04-21-003C simply says to make the switch, but mentions nothing about compatability issues).

 

I would like to make the switch to synthetic (M1 75W90) and am wondering if I need to change out the vent tube or other part(s) in the front diff. I am more than willing to do this, especially if it will rectify my pukeing problem described above.

 

Assuming any parts need to be switched out to make the change to synthetic, or to rectify the above problem, any info on part numbers would be great! I am unable to find any RPO code detailing the front diff (if one exists), but will supply any information I am able to answer the above questions.

 

Thanks much!!!

[ken1mod]

I had a venting problem once and I fixed it by removing the little twistie cap and putting a length of tubing on it and routing it to a higher location. I also bought a fuel filter that fit the tubing to act as an air filter. worked great and kept water out too.

 

ken

[ChevyTech007]

Synthetic would help. Make sure your vent cap is in the vertical position, that is very important. I had one years ago doing that and the best I remember the fix was the take the top off the cap and there are 4 slots, I had to take a die grinder and increase the depth of the slots to increase the air flow. Don't know if that makes sense but pull real hard on the cap and I think you will see what I'm talking about. Also the slots could be clogged.

[fossil]

The reason for puking fluid is that the level is too high. It should preferably be about 1/2 to 5/8 inch below the fill plug

[MS3DALE]

Dave,

I think this is what your looking for.

Rich.

 

Document ID# 1548733

 

 

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Subject: Info - Use of Synthetic Front Axle Lubricant For 4WD Vehicles Sold in Cold Weather Climates #03-04-19-001B - (09/03/2004)

 

Models: 2002-2004 Chevrolet Avalanche 2500, Silverado 2500/3500, Suburban 2500

 

2002-2003 Chevrolet Silverado 1500HD

 

2002-2004 GMC Sierra 2500/3500, Yukon XL 2500

 

2002-2003 GMC Sierra 1500HD

 

with Four-Wheel Drive and 9.25" Front Axle Assemblies and Built Prior to April 1, 2004

 

 

 

 

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This bulletin is being revised to update vehicle applications, part numbers and fluid fill information. Please discard Corporate Bulletin Number 03-04-19-001A (Section 04 -- Driveline/Axle).

 

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Important: This bulletin is intended for vehicles sold in very cold weather climates, especially those in Alaska and certain regions of Canada.

Important: This bulletin DOES NOT apply to vehicles built after April 1, 2004. Vehicles referenced above that were built after April 1, 2004 were manufactured with front axles containing synthetic axle lubricant and do not need to have the front axle fluid inspected or changed.

Front axles in the above-listed vehicles built before April 1, 2004 are manufactured with mineral-oil base axle fluid. Because of the 9.25" front axle assembly's internal design characteristics, there may be insufficient lubrication flow at very low ambient temperatures (-24°C (-12°F) or below). This may contribute to premature pinion bearing wear if a vehicle is driven extensively in very low ambient temperatures.

Important: Please be certain that PDI personnel know to perform the drain/refill procedure all year round (not just in the cold weather months).

New vehicles that are expected to operate extensively in 4WD in temperatures below -24°C (-12°F) should have their front axle fluid drained and refilled with synthetic axle lubricant during PDI or before delivery to the first retail customer.

Follow the Front Drive Axle Lubricant Replacement procedure found in the Service Manual (SI Document ID #673354). It is not necessary to flush the front axle assembly. Use Synthetic Axle Lubricant, P/N 12378261 or P/N 89021677 (Canadian P/N 10953455 or P/N 89021678 ). Each of these part numbers is the same axle lubricant, with differences in packaging only. Fill to a level between 6 and 9 mm (0.25 in to 0.375 in) below the bottom of the fill plug.

For vehicles that have the axle lubricant changed, the front axle vent hose connector assembly will need to be inspected.

Important: Front axle assemblies with a vent hose connector assembly that is white in color do not need to be changed.

If the vent hose connector is black in color, it will need to be changed so that the O-ring seal is compatible with the synthetic lubricant. Install vent connector, P/N 12479390 . Follow the Front Drive Axle Vent Hose Connector Replacement procedure in the Service Manual (SI Document ID #843184).

Parts Information

Part Number Description Qty

12378261 or 89021677

(Canadian P/N 10953455 or 89021678 ) Oil, Synthetic Gear 2

12479390 Connector, Axle Vent 1

 

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation Description Labor Time

*F0011 Fluid, Axle and Differential (Front) - Drain and Fill 0.5 hr

Add To Replace Front Axle Vent Hose Connector 0.1 hr

*This is a unique labor operation number for use only with this bulletin. This number will not be published in the Labor Time Guide.

 

 

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

 

 

© Copyright General Motors Corporation. All Rights Reserved.

 

 

Document ID# 1548733

 

 

 

Dave,

A few other things....There is no RPO Code for the axles,I wish GM would use them for the axles but they don't.

Secondly the bulletin mentions the 9.25" ring gear,You have the 8.25" ring gear,Don't worry the axle vent connectors are the same for all axles.

Third of all here is something else that might help you....

 

 

Axle Vent Hose Fluid Leak

 

 

 

An axle fluid leak that appears to be from the end of the axle vent hose most often occurs during hot ambient temperatures and/or while towing.

 

Installation of filter (p/n 5651682) will act as an accumulator and prevent fluid from being forced out the end of the vent tube. Install the filter vertically in either direction approximately 10-15 cm (4-6 in) from the end vent cap of the hose or where convenient. Retain the filter using the supplied hose clamps and secure the filter and hose to prevent damage.

 

 

 

 

 

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