

⚙️ Shift smoother, ride harder — the gear oil your V-Twin deserves!
Red Line 42804 is a premium full synthetic 75W140 gear oil designed specifically for V-Twin transmissions. Featuring advanced shockproof technology, it reduces transmission noise and clunk while maintaining optimal temperature and thick oil films for superior gear protection. Trusted by powersports enthusiasts since 1979, it’s compatible with UTVs, ATVs, and sportbikes meeting JASO MA/MA2 standards, ensuring smooth, quiet shifting and enhanced gearbox longevity.






| ASIN | B004X973EA |
| Best Sellers Rank | #15,516 in Automotive ( See Top 100 in Automotive ) #53 in Transmission Fluids |
| Brand | Red Line |
| Brand Name | Red Line |
| Container Type | Bottle |
| Customer Reviews | 4.9 out of 5 stars 1,815 Reviews |
| Global Trade Identification Number | 00083522428040 |
| Included Components | V-Twin Transmission Oil |
| Item Form | Oil |
| Item Type Name | Car Gear Oil (1 Quart Bottle) |
| Item Weight | 1.7 Pounds |
| Liquid Volume | 32 Fluid Ounces |
| Manufacturer | Red Line |
| Material | Synthetic |
| Package Information | Bottle |
| Recommended Uses For Product | Transmission Oil |
| UPC | 083522428040 |
| Unit Count | 946 Milliliters |
| Viscosity | 75W140 |
| Warranty Description | Warranty, Parts:Parts |
Y**A
repeat use, good oil
good oil, affordable, works great, color is fun, and smells like fresh oil. works well in the trans for my v twin.
T**E
Shift quiet and smooth!
Put in my street glide. Good stuff so far. Shifts a heck of lot quieter and finding neutral isn't an issue thus far. Think I like it better than amsoil's trans fluid.
B**H
If you have a H.D. Dyna, you NEED THIS!
HUGE difference in gear box sound and feel! Smooth and slick shifting. I am sure this solves the well known automatic tensioner problem too!!! ONE THING very interesting to know is that it is NOT compatible with engine style oils and would NOT be a good idea to add to ANY existing oil ~ YOU MUST use this at REPLACEMENT. I poured this oil into a container with the engine oil and it CLEARLY SEPARATED!!! BTW, It’s REDLINE! What’s not to like?!
O**R
Great Quality
This is my go-to V-Twin transmission gear oil in my Harley touring bikes. Great quality oil that keeps my transmissions in tip top shape over the years. Just make sure you change your fluids regularly.
P**H
Big Improvement
I decided to try this on the advice from my Harley dealer. I was complaining about the loud shifts down to 1st gear, hard clunks when shifting and the noisy 5 gear whine in my 2007 Road King with the six speed transmission. It is a know problem that 5th gear on theses transmission is noisy, it is a straight cut gear which is noisy (thats why they fixed the problem later). I tend to be a bit conservative when it comes to venturing outside of genuine Harley parts and accessories. I have always used the SYN3 in all three cases on the bike and switching to something other than the Harley oil took me a while to do. The Redline oil is certainly red!! Looking like red Peto-bismal versus what I would call traditional transmission fluid or oil. It is 100% synthetic which was a must for me and changing it was as easy as could be. If you are unsure on how to do it there are lots of videos on the web outlining how to do it. I did a quick 75 miles run after the change and there is a big differance!! Shifts are smoother through all the gears, 5 gear is significantly quieter and I also believe the bike feels a bit less "buzzy" than it did before. Have just come back from a 1800 mile 4 day ride I certainly believe the changes are more than just in my head. I am a believer in this product and will use it from now on!
C**A
The only trans oil I’ll put in my five speed.
I have been using this oil in the primary of my track day Buell XP 12 since 2006. Lightyears better than the HD branded stuff. I know that it’s a full PAO base synthetic and I know it has the correct additives package for an HD primary straight cut five speed. 20 years of spirited riding and I haven’t had any issues related to the transmission. It handles southern summer race day temperatures and the occasional ham fisted shifts with out blinking. Some of my riding buddies, use it in their sportsters that they ride as regular commuters, through city traffic, year round. I like it, they like it, what else can I say?
I**T
Y
Good product
J**S
Good quality.
Redline is great transmission fluid for the Harley. I won’t run anything else. Smooth shifting. Amazon got it delivered quickly. Very happy.
Trustpilot
2 weeks ago
2 weeks ago