good info HD 6 speed

Discussion in 'General Harley Davidson Topic' started by harleyflhrs, Aug 31, 2010.

  1. harleyflhrs

    harleyflhrs New Member

    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.

    BOWHIKER Junior Member

    So why do you say to run dyno oil in tranny ? I thought a full synthetic would be better ?
  3. dbmg

    dbmg Experienced Member

    This sounds like a catastrophic failure. How were bikes maintained and ridden? With the trans plug at the lowest point there is not metal debris on magnet?
    With the large touring crowd on this forum there is not alot of talk of transmission failure. With proper maintenance using Spectro or Redline products and normal riding I find it hard to believe Harley could produce such a inferior product.
  4. Hoople

    Hoople Account Removed

    This is a "Print & Save" thread. GREAT info and thanks for taking the time to write it all up including the detail part numbers..

    Do you happen to know what oils were used in failed transmissions?
  5. Tramp60

    Tramp60 Member

    Hey Hoople, Syn3 in mine. Every bearing that harleyflhrs is talking about had to be replaced @ 31k.
  6. Hoople

    Hoople Account Removed

    That's almost unbelievable. Doesn't that oil have any protective film at all. It must protect slightly better than kerosine. Incredible product.

    BUBBIE Well-Known Member

    Yes it is.... Just THINK of how many people are going to lawyer-up to go AFTER HD in the future if they Don't stand behind their BAD advice for Using SYN3 (SIN3) in all 3 holes! A Lawyers Field Day!

    That is why I use Redline Shockproof Heavy......

    ""Shocking"" to hear of such early problems from using SYN3 that the HD Co. suggested to use and THEY put it in a lot of New bikes pre-delivery...

    Bet that is going to cost them $$$$$$$$$$$$$...

  8. craig Lee

    craig Lee Active Member

    Have to chime in here. Harleyflhrs has said it all and know we've gone around and around on this 6 speed tranny situation. Replaced my mainshaft bearing at 31,000 miles on my '08 SG for the above reason and was going out again at 42,000 because of the clutch hub splines being worn and going through the mainshaft bearing when finally put in the Baker DD7 in which I was hoping no regrets. He does mention Baker using the same bearings. Oh well, will keep the forum in the loop. I was previously using Motul 300 75/90 and have switched to Spectro Platinum Heavy for 6 speeds.
  9. ironmark

    ironmark Junior Member

    33,000 0n m 08 and no problems yet !! I use Mobil 1 75-90 gear lube & there is nothing on the magnet yet . Maybe the people that own the bike just dont do the correct maintanence .
  10. rancid

    rancid Active Member

    worked on 100s of 6 speeds and havnt seen any failures, i change formula + every 8000km, same deal with bikes on syn3, and as dbmg said there ant much said about trans failures.