I own 2003 S10, there is a TSB that clearly states do not use limited slip additive.
LOCKING DIFFERENTIAL LUBRICANT (SERVICE INFORMATION) #91-4-109
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 10950849).
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. The use of additives will delay the engagement of the locking mechanism and may decrease axle life.
VEHICLES/COMPONENTS INVOLVED: Some light duty trucks equipped with locking rear axles, RPO G80.
SERVICE PARTS INFORMATION: Part Number Description 10950849 Lubricant, Rear Axle (1 litre) Parts are currently available through CANSPO.
The only difference now is they do not recommend the use of 80w-90 and instead recommend the use of GM 88900401 75w-90
Cool, nice truck.
The thing is, and the issue I have with the arguement is, there are millions of people who have a GM truck...... Any and all 1\2 tons and above pickups for the last 25 years have had the G80, automatic locking differential, such that it is not even an option not to buy one with it, in other words, they are standard equipment.
Valvoline's gear oil
sharena21.springcm.com
Mobil 1 gear oil
Amsoil gear oil
etc etc......
ALL have LS additives in them.
So, all these listed companies above have made, in great and available quantities, a gear oil that you cannot use, in the most popular pickup chassis, work van chassis, (P30-P32)UPS chassis, motorhome chassis, in the USA? I think not.
Some gear oils, such as MobilLube HD, or Supertech clearly note "for top off" in LS diffs. Not suitable for limited slip diffs.
I think the arguement that an additive is not directed to be added to the oil is correct.......because the oil already has the modifier in it. Especially in the grape smelling AC delco stuff, which no one in their right mind buys.
The company I used to work for, before I went out on my own as a business, exclusively used GM trucks, 2500 and above. Sold them for cash normally around the 200k range........never had an issue with any rear end........using Valvoline 75w90 regular gear oil off the shelf, marked as LS, straight out of the drum.
If you use gear oil without the LS additive, (((and))) you get in a situation where the axle locks up, getting it to unlock can be difficult, and loud. Most people never even get into a autolocking situation, and would never know the difference.......
Especially people who just quote some text like the gospel without experience of what they are talking about.
