From small dealer, Feb 2006...
Additional information has shown that if you have LSD you should also ask that one 4 oz. bottle of GM #1052358 Limited Slip Axle Lubricant Additive be added to fluid.
Quote:
Rear Axle Pinion Seal Leak - keywords axle fluid leak pinion repeat #PIP3671B - (Feb 2, 2006)
Rear Axle Pinion Seal Leak
2003-2006 Cadillac CTS
2004-2006 Cadillac SRX
2005-2006 Cadillac STS
2006 Pontiac Solstice
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
The rear axle pinion seal may experience a fluid leak condition. During seal replacement, the new seal may still leak as work on the vehicle is being completed. It is possible that when replacing the seal, the rear axle lube is seeping through the pinion bearings. The lube then gets past the rubber seal and gets trapped behind the metal "dust shield" before the pinion yoke is installed. When the dealer installs the pinion yoke, the trapped fluid is squeezed out and gives the illusion of a continued leak.
Recommendation/Instructions:
Inspect the new seal for the presence of the internal "garter" spring and make sure it is there. If not, use a seal that does have it. Also inspect the new seal for metal contamination in the grease used to lube the seal lip. If there is any contamination, discard the seal and use only a debris free seal that is supplied with grease. Prior to replacement of the pinion seal, on vehicles built in October 2005 and later, mark the 12 o'clock position of the seal before it is removed. Clean the residual lube from the old seal and use a permanent marker to mark it. Engineering is looking at all returned seals from this time period and this will help their investigation.
When replacing the pinion seal, first drain the rear axle fluid. This also helps remove metal contaminants that may be present and may have caused the initial leak condition. Next, remove the leaking seal. Install the new seal and yoke. Lastly, refill the rear axle. This should prevent the lube from being trapped behind the dust shield.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
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.
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While the bulletin doesn't go into why it is happening, it does have important information on proper repair procedure. It also points out a possible "illusion of a continued leak" that can appear to be happening after replacement.
The October date also gives the idea that changes have been made.
Hope the information helps.