Red Line 58204 Heavy Shockproof Gear Oil - 1 Quart

This is what your Harley transmission wants. My '07 softail deluxe loves it. Completely eliminated the hard 1st & 2nd tough shifts. Neutral first time every time. Turned the shift " clunk" into a quick snap. Worth every penny. Packing and shipping was top notch. Whoever packed it knows how to secure the contents of a package.

Fast shipping and fairly priced compared to other places

Red line heavy shockproof gear oil is the best by far for any Harley trans. It will shift like a dream (and you can find neutral) will also quiet down the clunk into gear. Let's be real here, its a Harley with a chain drive primary and its; going to clunk. If your one of th0se who hates the clunk, buy a Honda.

I am writing this review for the nay-sayers of this product. I have owned Harleys my entire life and Harley transmission have some noise issues going into 1st gear. This oil will stop that and the transmission will shift smoother than it ever has. Years ago I took my motorcycle into the shop for fluid change. I got home from the shop, which was around 70 miles and noticed the transmission was shifting differently. I checked the transmission oil and none was in it. They forgot to fill it up. The Red-line oil is so thick that it coated the gears and bearings and protected them from damage. If this would of been any normal oil. The bearings would of been damaged and the transmission would of needed rebuilded or even replaced. This oil saved me a minimum of 1,500 to a maximum of 8,000. I swear by this oil and will not run any other.

Used this in my 1999 Subaru Impreza Outback Sport with noisy front and rear differentials. I threw some mobil0-1 75w-90 in each diff for about 1k miles to rinse things out. Just dropping the beat-up, dark diff fluid and going to Mobil 1 was a marked improvement alone.After running that sacrificial fluid for 1k miles, I drained it (and it was in much better shape, but still appeared QUITE DIRTY) and installed some Lucas full synthetic 75w-90 gear oil with about a half of the Heavy Shockproof quart going into the front and a half going into the rear diff. I put the Redline in first so it would mix better. Both my front and rear differentials are OPEN (not LSD; if you have an LSD, DO NOT USE this redline shockproof series).Immediately, I noticed that the diffs were notably quieter and that the car even accelerated and coasted more easily than even with the mobil-1 gear oil. I used the heavy shockproof because I'm in Florida and it never gets very cold here (it dips below freezing for a few hours, a few nights of the year, but only just below). If you are not in a southern state (FL, Texas, AZ, NM, LA, etc), I would advise selecting the lightweight shockproof instead.Overall, I'm extremely satisfied. If you have an open diff, or an air locker (anything but an LSD), you owe it to yourself to add a portion of shockproof to your diff. Quieter means cooler. That's always a good thing.Also, NEVER add this to any transmission. Even a manual. Your synchros will be permanently too slippery to work properly.

I put this in my 05 Harley Fat Boy FLSTFI's 5 speed transmission. I usually use Amsoil's V twin trans fluid, but didn't have time to order any and heard good things about the Redline shockproof. After about 150 miles, I can say I prefer the Amsoil. For me and my bike, natural is easy to find in both. However, it noticeably shifts gears harder with a more pronounced clunk than I had in the Amsoil. I will be switching back to Amsoil. Overall, it is a good product but I like how my bike shifts smoother with the other product.

Best transmission oil for a Harley

Use the Redline Heavy Duty Shockproof in my 2007 Harley Street Bob. The transmission runs smooth as silk on this stuff. Makes a noticeable difference compared to other gear oils on the store shelves. Prior to Redline heavy duty shockproof, I had run Lucas and Royal Purple gear oil in my Harley tranny...both were fine but I'm not going back to them after hearing and feeling the difference of the Redline in there. Can't beat it...highly recommend. It'll make your transmission run smoother, cooler, and quieter. Well worth it, don't bother with other gear oil and definitely do not run Syn-3 in the transmission. That stuff is trash.