Few drivers realise that limited-slip differentials depend as much on oil chemistry as on hardware. Friction modifiers in LS gear oils tune how smoothly clutch packs engage, shaping turn-in stability and traction over ruts and jump landings. In rally use, sudden load spikes and temperature swings can shear the film and invite chatter; a stable base oil and balanced additives help maintain a predictable lock without harshness. For mixed gravel and asphalt and frequent tight exits, an LS-rated gear oil of suitable grade, such as 75w140 LS GL-5, supports consistent torque transfer.
How LS gear oil chemistry shapes rally differential behaviour
Transmission Oil/Manual

75w140 LS GL-5
IBC 1000L:6550 €
Drum 205L:1390 €
Canister 20L:165 €

75w80 GL-4/5
IBC 1000L:3350 €
Drum 208L:695 €
Canister 20L:79 €

75w90 GL-4/5
IBC 1000L:3250 €
Drum 208L:685 €
Canister 20L:75 €

75w90 LS GL-5
IBC 1000L:6150 €
Drum 205L:1350 €
Canister 20L:149 €

80w140 GL-5
IBC 1000L:3750 €
Drum 205L:789 €
Canister 20L:85 €

80w90 GL-5
IBC 1000L:2200 €
Drum 208L:499 €
Canister 20L:53 €

80w90 LS GL-5
IBC 1000L:2200 €
Drum 208L:499 €
Canister 20L:53 €