After doing alot of research I discovered some of the top Harley drag racers use Red Line Shockproof transmission oil in their Harleys. It is made for aircooled V twin trans. Color is red and it smells just like gear oil. Very thick.
After changing the oil I discovered my bike goes into neutral much easier and shifting is much softer. It took away atleast 50% of the clunk Harley's have.
I highly recommend you run it in your trans. I just wanted to share this with you. It seems most Harley riders use 20w50 in all three holes, but it just didn't seem right to me. I did put Mobil1 20w50 in the engine and primary.

 

I have always felt gear oil was better for gears, but I use Lucas gear oil in my trans.

 

Same here but use Amsoil 75W-90 gear oil in the tranny and shifting is smoother and more quiet.

 

How long has it been since you changed the tranny oil?

 

I use Red Line but not because a drag racer does. Keep in mind that the fluids in a race bike is changed very often so it never gets a chance to break down. I will decide at changing time if I keep Red Line or go to Amsoil.

 

yep, Amsoil severe gear in mine.

 

My bike has less than 6K miles so that was the 1st time I have changed it. It was serviced at the Harley dealer when I bought it. It had 3K when I bought it.

 

I use to drag race bikes and understand they are changed more often. That was not the sole reason for using the RedLine oil. I chose it because of a Harley tech, and drag racer of 30 yrs told me about it. He said, quote,do not use 20w50 in the trans gear box. It will not hurt the gears, but gear oil is the preferred oil because it coats the gears and they are exposed to alot of load and shock. I ride my bike fairly hard and wanted to protect my investment as well as possible. My whole point to this post is to share how much smoother the transmission operates compared to what ever thin oil was in the trans. And it looked like motor oil.
Please understand I'm not a Harley expert. I am a aircraft mechanic and a ex ASE certified tech. I wanted to change all my oils and after reading about what others ran in their Harleys, It seems that most use 20w50 in all three,eng,pri and trans. I felt like Ford ATF or gear oil would be better in the trans than motor oil. After riding my bike with the RL, if it continues to perform as it did yesterday, I will stick to the Red Line trans oil in my transmission. I will let you guys know how it does in a couple weeks.
Frank

 

My indie mechanic pointed out a tranny that he had pulled the day before. It had Redline and the red stuff was still heavily coating the gears. He highly recommended RedLine and made a few more recommendations to me that soon proved true. He was a wise old man and knows what he's talking about.

At the next fluid change I put the stuff in my tranny. Didn't notice anything different, but I haven't had any problems either. It's certainly good stuff and your gears never run dry.

 

Have used the Red Line shockproof in tranny for quite a few years.

Many years ago I had some warranty work done on my RK. When I got home I thought the tranny was a bit off...they had given me back the bike with NO oil in the transmission. All that was in there was the residue from the Red Line I had been running during the 75 mile ride home.

Put some Red Line in it and rode it another 40k miles before selling it...never had a problem.

Good stuff.

Kevin