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Red Line V-Twin Primary Case Oil


  • For 1984-to-present V-Twin American motorcycle engines, including Evolution, Twin Cam, and aftermarket engines of similar design
  • Same fluid as our famous MTL gear oil
  • Improves clutch operation while reducing wear and temperature
  • Where most synthetics are too slippery for clutch operation, this friction-balanced product is balanced to provide less slip, smoother operation, and helps to apply more power in modified engines
  • This product is for use in the primary chaincase with wet-diaphragm spring clutches

Typical Properties:

API Service Class GL-4
SAE Viscosity Grade (Motor Oil) 5W30
SAE Viscosity Grade (Gear Oil) 75W80
Vis @ 100°C 10.4
Vis @ 40°C 54.1
Viscosity Index 185
Pour Point, °C -50
Pour Point, °F -58
Brookfield Vis @ -40°C, P 120

4.7 / 5.0
6 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Stars
Bang for the Buck
5.0 / 5
Would Purchase Again
5.0 / 5
5.0 / 5
Would you recommend?
Yes (1)
not just another primary oil
Changed out after 25K of HDs Syn3. No clunk into 1st from nuetral. Clutch plate rattle dissapered. No slide during heavy acceleration. May have to look at Redline for tranny after Amsoil made really no differance in noise and stiffness at shift. '08 FLSTC w/ 25K
June 25, 2010
Redline oils really are better
My local Cycle Gear store keeps the entire line of Redline in stock.
August 1, 2014
Will be buying from them a lot
Geat oil
November 15, 2013
Redline V-Twin Primary Case Oil quites noise
Redline improves shifting and clutch action with reduced noise.

PROS: Smoother Clutch Action, Easier shifting

July 8, 2015
Bang for the Buck
5 / 5
Would Purchase Again
5 / 5
5 / 5
Would you recommend?
Great Oil For a Harley
Since Harleys are air cooled I wanted the best protection from heat I could get. Red Line seems to hold up very well and I have more confidence between changes during the hot summers down in the south. Highly recommend this oil over screaming eagle, and any other brands I've seen.
September 26, 2016
1 year ago
Works Great
Very happy with the product. Easier to find neutral and clutch operation/engagement is improved.

PROS: Better Clutch Engagement, Better Shifts, Smoother Shifts

September 15, 2015
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Product Style Item # Manufacturer Product # Availability
1QT 952561 42904 In Stock: Ships within 24 hours