Good information on HD 6 speeds First of all if your bike is still under warranty this is good thing. “So before your warranty expires” I stress that u take your transmission inspect cover off, one must remove exhaust and muffler on right side, then remove transmission inspect cover (6 Allen head bolts). Once u have done that and if u can’t, it’s about hour labor charge at your dealer (well spent 100.00 dollars). Look in the bottom inside of trans inspect cover for grey slugs and metal particles in this area. Appearance of this, then your transmission needs complete rebuild, all bearings, seals, gaskets need replacement. Inspecting at your oil plug magnet on regular services will not tell u anything, trust me on that one. Now (06 to10 models) any oil leaking from primary or growling sound from primary area is good sign you need to investigate. This grey slug and metal u will see on inspect side got there, because the swirl of the oil throws the entire particles to the inspect cover side. “Maybe this good thing”, that’s where it pools up and stays; these metal particles are caused by failure of mainshaft bearing which is a two piece roller bearing. HD # 8967, which is a FAG bearing # 559796. This two piece bearing has three races, two sets of roller bearings. Good inspection of this bearing once transmission is torn down ( 8 hours labor charge or more) u will see on “front wheel side” of the mainshaft bearing largest inner race is galled in this area only, back side of same race looks normal.. This tends to make me believe that there are added forces to this front area of mainshaft bearing. ( Why?) The other two races of this mainshaft bearing are galled completely around both races. I have now rebuilt three HD 6 speeds, One Dyna and two FLH’S. same story for each identically, only different is mileages. Mostly from my experience 15000 miles to 28000 miles trouble starts with this mainshaft bearing. Tomorrow I start my fourth transmission tear down on customer’s transmission. Now little word about your inner primary bearing and clutch hub bearing. Inspect yourself; remove primary cover and two bolts and chain tensioner, then slide out drive sprocket with chain and clutch hub to inspect. Here is heads up on these bearings. Failure of inner primary and clutch hub bearings is caused by your clutch hub splines cracking off. Inspect clutch hub splines to see if chucks are missing inside. These chunks go right into both bearings in time. It’s not the mainshaft splines; it’s the clutch hub splines. So inspect carefully. Failure of both mainshaft bearing and inner primary bearing can occur at anywhere from 15000 mile to 45.000 miles. At this top mileage mentioned, I would most definitely inspect and hope u still under warranty, just remember HD service bulletins and warranties are in house. Its HD’S best kept secret to not having recalls or really letting public information out. Opinion, HD 6 speeds (06 to10 models) are troubled until HD provides updates. I have phoned Baker transmission and they use same bearings and “possibly considering” making redesign on this bearing. But don’t hold your breath. Once U are off HD warranty, there is no update by HD as of yet to transmission problem. So new HD bearings are same old ones pron to failure cause by????. ( Bummer) HD knows there is problem and as usual put hands in the air. Normal for HD. So use that warranty well. Last but least,” run dinosaur oil” in primary and trany. The engine, run what u like for type of oil. Try this, when at traffic stop light and your in neutral, pull in clutch when u see amber light. This give time to slow down motion and u get less chunk in gear. Personally, this saves on splines of clutch hub or first start ups pull in clutch early. Before engaging trans... 4 all who doubt, inspection says all. Catch early save money, nothing wrong with that.