fyi
When you change lube in a LSD axle, you should drive in figure 8's for about 5 times to work the new lube into the clutch's. This method will engage the LSD where normal driving may not accomplish the same thing for many many miles. Its possible this was the first time your posi engaged that you heard the noise.
This is an excerpt from a GMC TSB for informantion purposed only. I realize you have a different make but the info contained here may be of value. Note-GM uses Eaton LSD and Lockers.
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 with SAE 80W-90 GL5 (P/N see below). 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.
Here is another TSB, note they recommend mixing the LS additive with lube and then adding to rear axle.
Subject: Shudder or Bind On Low Speed Turns - keywords axle differential
groan growl moan noise rear slow vibration #PIP3152G -
(05/03/2006)
Models: 2004-2006 Cadillac SRX, CTS, CTSV
2005-2006 Cadillac
STS
2006 Pontiac
Solstice
2007 Saturn
Sky
Equipped with Limited Slip Differential (RPO -
G80)
This PI is being updated to include 2007 Saturn Sky and also update the Part number for the axle
fluid and include part number disclaimer. Please discard PIP3152F
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Service Information
Customer may comment of a shudder or bind from the rear of vehicle on low speed turns such as
parking lot maneuvers on vehicles equipped with G80 limited slip rear axle. This condition may be more
noticeable with the vehicle at operating temperatures.
Recommendation/Instructions:
Drive the vehicle to warm the rear axle and then drain the axle fluid. Refill with just the 89021677 (in
Canada, use 89021678) axle lube and drive the vehicle about 10 minutes performing mostly parking lot
turning maneuvers. Drain the rear axle again and mix 1200 ml of 89021677 (in Canada, use 89021678)
and 74-89 ml of 1052358 (Canadian P/N 992694) additive outside of the axle and then fill the rear axle
with this mixture and re-evaluate.
Part numbers are subject to change. Use any superseded part numbers if the part numbers in this
document become discontinued.
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.
[ August 20, 2006, 07:11 AM: Message edited by: Mike ]
