Hello oil gurus,
Chevrolet recommends when changing the gear oil, adding a limited slip axle lubricant additive since the Camaro has a limited-slip axle.
Modern gear oils do meet API-GL5 & MIL-L-2105D specifications:
- They already have up to 6.5% of friction reducing additives
- Specifically for use in differential gear units with limited slip
In regards to this, I found a very nice document: https://www.widman.biz/uploads/Transaxle_oil.pdf
Especially this part is very interesting:
--- snip BEGIN ---
Transaxles
So,what do we put in transaxles where the transmission and differential are combined in one unit? This is a good question, and the answer lies in the design and surface area of the gears. If the contact surfaces of the gears arebig enough to carry the weight and torque necessary, we depend less on the oil and its additives. If the surface area is compact, we need to depend more on the additive's ability to handle the boundary lubrication. When we have transaxles, we have to depend on the manufacturer to tellus what product is correct.
When we have transaxles,we also need to be aware of whether the differential portion uses Limited Slip"LSD" technology of some kind that limits the slipping of the wheels in mud and snow. This requires an additive that lets a clutch bind the wheel movement together at a certain speed differentialof the wheels. This additive can be in any oil. Many GL-5 oils have a small amount. This is often enough for some differentials as long as they were not rinsed out. Some systems needmore additive than others. You can usually tell if you need more additive by making a U-Turn. If the inner wheels click or try to lock up on the turn, you need more additive. Often an oil that has a little of this additive will say it is satisfactory for "service fill" or "top-off".
How can you tell whether or not you have a limited slip differential? That is the easy part: Jack up both driven wheels and spin one of them with your hand (transmission in neutral) if the other wheel spins the same way, you have a limited slip differential. If it spins in the reverse direction, you do not. You can also just jack up one wheel and try to spin it. If it refuses to turn, or turns with a lot of resistance, and the car is in neutral, with no brake on, you have limited slip
You will find numerous wrong comments on forums and other sites where users claim that GL-4 means LSD. That is totally false. A check of the API site could have set them straight
--- snip END ---
Based on these findings, I have following questions?
- Is the recommendation from Chevrolet based on the latest oils and their specifications obsolete?
- In case I would use a oil that meets API-GL5 & MIL-L-2105D specs, would I still need to use the recommended LS additive?
For a 5th gen Camaro SS AT / LS99, what would be the better oil of choice?
https://www.ravenol.de/en/products/usage/d/Product/show/p/ravenol-ls-75w-90.html
or
https://www.ravenol.de/en/products/...getriebeoel-sls-sae-75w-140-gl-5-ls.html
And as already asked, would I need to use any additional LS additive when I use either of these gear oil?
Cheers,
Niels
Chevrolet recommends when changing the gear oil, adding a limited slip axle lubricant additive since the Camaro has a limited-slip axle.
Modern gear oils do meet API-GL5 & MIL-L-2105D specifications:
- They already have up to 6.5% of friction reducing additives
- Specifically for use in differential gear units with limited slip
In regards to this, I found a very nice document: https://www.widman.biz/uploads/Transaxle_oil.pdf
Especially this part is very interesting:
--- snip BEGIN ---
Transaxles
So,what do we put in transaxles where the transmission and differential are combined in one unit? This is a good question, and the answer lies in the design and surface area of the gears. If the contact surfaces of the gears arebig enough to carry the weight and torque necessary, we depend less on the oil and its additives. If the surface area is compact, we need to depend more on the additive's ability to handle the boundary lubrication. When we have transaxles, we have to depend on the manufacturer to tellus what product is correct.
When we have transaxles,we also need to be aware of whether the differential portion uses Limited Slip"LSD" technology of some kind that limits the slipping of the wheels in mud and snow. This requires an additive that lets a clutch bind the wheel movement together at a certain speed differentialof the wheels. This additive can be in any oil. Many GL-5 oils have a small amount. This is often enough for some differentials as long as they were not rinsed out. Some systems needmore additive than others. You can usually tell if you need more additive by making a U-Turn. If the inner wheels click or try to lock up on the turn, you need more additive. Often an oil that has a little of this additive will say it is satisfactory for "service fill" or "top-off".
How can you tell whether or not you have a limited slip differential? That is the easy part: Jack up both driven wheels and spin one of them with your hand (transmission in neutral) if the other wheel spins the same way, you have a limited slip differential. If it spins in the reverse direction, you do not. You can also just jack up one wheel and try to spin it. If it refuses to turn, or turns with a lot of resistance, and the car is in neutral, with no brake on, you have limited slip
You will find numerous wrong comments on forums and other sites where users claim that GL-4 means LSD. That is totally false. A check of the API site could have set them straight
--- snip END ---
Based on these findings, I have following questions?
- Is the recommendation from Chevrolet based on the latest oils and their specifications obsolete?
- In case I would use a oil that meets API-GL5 & MIL-L-2105D specs, would I still need to use the recommended LS additive?
For a 5th gen Camaro SS AT / LS99, what would be the better oil of choice?
https://www.ravenol.de/en/products/usage/d/Product/show/p/ravenol-ls-75w-90.html
or
https://www.ravenol.de/en/products/...getriebeoel-sls-sae-75w-140-gl-5-ls.html
And as already asked, would I need to use any additional LS additive when I use either of these gear oil?
Cheers,
Niels
