BEL-RAY SKU: 840-1583

Bel-Ray Big Twin Transmission Oil - 85w140 6gal BIB

$281.95
Free shipping on orders $99+ · Best value guarantee
From $23.49/mo with Affirm. See if you prequalify
IN STOCK — Ships within 24 hours
Free Shipping on orders $99+
Best Value Guarantee
30-Day Returnssee policy
Authorized Dealer — sourced direct
NOT SURE ABOUT FITMENT?

Bel-Ray Big Twin Transmission Oil 85w140 is a full synthetic gear oil formulated for Harley-Davidson and Indian Motorcycle transmissions and final drives with separate lubrication systems. Delivers wear protection, reduces gear noise, and improves shift quality in air-cooled and liquid-cooled Big Twin engines.

Features

  • Formulated for separate transmission and final drive systems
  • API GL-5 specification
  • Wear protection extends gear life
  • Reduces gear whine and improves shifting smoothness
  • Suitable for air-cooled and liquid-cooled Big Twin transmissions

Specifications

  • Brand: Bel-Ray
  • Manufacturer Part #: 301828150033
  • UPC: 690509408522
  • Viscosity: 85w140
  • Volume: 6 gallons BIB (Bag-in-Box)
  • Weight: 45 lbs
  • Dimensions: 18 in L x 7 in W x 13 in H

Fitment

Fits V-twin motorcycles with separate transmission and final drive lubrication systems, including Harley-Davidson and Indian Motorcycle Big Twin models.

Frequently Asked Questions

What does API GL-5 mean?

GL-5 is the American Petroleum Institute's highest gear oil specification, formulated for high-pressure differentials and demanding gear trains like motorcycle transmissions.

Can I use this in both transmission and final drive?

Yes — Bel-Ray Big Twin is designed for both the transmission and final drive on motorcycles with separate lubrication systems.

Is this synthetic or mineral oil?

This is a full synthetic formula engineered for longer oil life and better protection in V-twin engines compared to conventional gear oils.

Will this quiet my transmission whine?

Bel-Ray's formulation is designed to reduce gear noise and provide smoother shifting, though some gear whine is normal in any motorcycle transmission.

How much oil does my Big Twin transmission hold?

Transmission capacity varies by model year and engine type. Consult your service manual or contact a Harley or Indian dealer for your specific bike's capacity.

BRANDBel-Ray
TYPEChemicals
SKU840-1583
WEIGHT45.0 lb
Please contact us to confirm fitment for your specific motorcycle, or check the product title for compatibility notes.
CUSTOMER REVIEWS
4.93
76 RATINGS
5★ 72
4★ 3
3★ 1
2★ 0
1★ 0
✓ VERIFIED
Jul 25, 2023

Bel-Ray big Twin oil for the win

Will not use OEM oil after buying Bel-Ray, this oil makes it very easy to find neutral, shifting seems smoother and less “clunky” sounding. It’s all I will be using from now on.

— DANIEL N
✓ VERIFIED
Nov 22, 2022

Bel-Ray is all I use in my Harley primary & trans. I’ve tried many and bel-ray makes shifting and finding neutral a piece of cake

— Anonymous
✓ VERIFIED
Sep 2, 2022

Bel-Ray transmission oil works great and allows very smooth and quiet shifting without the notorious Harley clunk.

— Anonymous
✓ VERIFIED
Jun 8, 2022

I have tried several different transmission fluids throughout the years for my Harleys and I think Bel-Ray is the best. It doesn't take out all the noise when shifting but it is the quitest of anything I have tried.

— Anonymous
✓ VERIFIED
May 31, 2021

Transmission shifts smoother now!

— Anonymous
✓ VERIFIED
Apr 14, 2021

used some on my wife she loved it.<br />need more for the bike though

— Anonymous