I have a 1991 Ultra Classic with around 17,000 miles. Every time I shift into fourth gear, there is a fairly loud seeming whine with a little of a knocking sound. Any ideas?

 

Are you shifting too soon and luggng the engine? The whine could be gear noise. If you are not running 75w90 or 85w140 gear oil in the trans try that for $10-15. Try shifting at about 10% more revs. If it still knocks it could be detonation (get better premium gas) or your compensator sprocket nut could be loose. But that comp should knock at start up in 1st gear.

 

Thanks for the reply! It whines any time I put it in fourth gear, and only in fourth gear. After I take off and reach fourth gear, or when I am going up a steep hill and downshift into fourth gear so I don't lug the engine. All other gears sound fine.

 

I have an 05 sportster.It whines in 3rd. I've never had a problem with the tranny.If you use a correct weight quality oil and correct level it should be OK.Don't know about the knocking though,I don't have that..It's better to listen to an H.D. whine than a woman..

 

I agree! I would rather hear the HD whine. I may have not described the "knocking" correctly. It is probably more of a low popping sound. I still wonder what is causing it to whine though. Would the Amsoil be a better choice of oil?

 

Amsoil is great, but I think it's a personal preference. go with what you like,, try afew if $$ is not a problem see what runs best, The "popping could be slippage from somewhere" but don't want to stear you in the wrong direction.. as I don't have an exact understanding of the noise..Synthetics are good but I've heard "Lucas Oil" has a good non synthetic for older engines...