Front Diff Fluid

[shaynet1979]

what kind of front differential fluid should i use?

[T-Bag]

what kind of front differential fluid should i use?

 

Your brand of choice, GL5 90 weight

[Fireman31]

75W-90 Synthetic, GL5 rated as stated above.....

[Nscott]

Royal purps 75w-90

[Bear]

For all the owners of 2004 and newer trucks it should be no problem just using the synthetic 75W-90 Synthetic, GL5 rated gear oil, as has previously been recommended. However for owners of 2003 models, one needs to check to see what color the vent hose connector is in the differential, as it could go either way.

 

If you are changing your front diff fluid to synthetic (and you should!) make sure the vent hose connector is white and not black or it could leak!!!

 

Drivetrain - Synthetic Fluid Usage in Front Differential

 

File In Section: 04 - Driveline Axle

 

Bulletin No.: 03-04-19-001B

 

Date: September, 2004

 

INFORMATION

 

Subject:

Use of Synthetic Front Axle Lubricant for 4WD Vehicles Sold in Cold Weather Climates

 

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

 

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).

 

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. 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 0-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.

[Krambo]

Good post bear. Mine is black, checked it today after "something" went wrong during a tuning session. I fear the worst but will be changing the oil to verify.