This can't be good.

Discussion in 'GS Boxers' started by bemiiten, Nov 26, 2006.

  1. johnjen

    johnjen I've Been Resigned

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    While the original shimming will still be close, changing the bearings will usually change the shimming measurement. If you want to use our method, try this. At room temperature make your measurements (write them down). Then freeze the tranny parts and re-measure the shimming dimensions while really cold. Then heat the parts up to say 200 degrees F and measure them again.

    Then determine the range of the shims from cold to hot. From here you can either split the difference or weight the shim dimension more towards the hot side (where the tranny usually operates)...

    It's a bunch of extra work but if you nail it, the tranny will shift like butta.

    JJ

    #41
  2. Gros Buck

    Gros Buck Beef = Packed Vegetables

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    I own a 05 1200gs that does the same thing. I heard Getrag transmission does that all the time.

    I double check with another GS at my dealer. Same noise. Whenever you put the bike on central stand with the wheel engaged and spinning in the back.

    This noise could be reduced with thicker oil.
    But I agrree it does not soung healhty ...:huh
    #42
  3. bemiiten

    bemiiten League of Adventures

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    The parts have arrived from Chicago BMW 3 weeks after I placed the order. Excellent turn around IMO. I had one (front) intermediate shaft bearing that was clearly bad and a leaking input shaft seal. The other two front bearings also show sings of overheating with the output shaft bearing discolored as bad as the intermediate, but turning smoothly. I decided to replace all six.
    I set up a dial indicator to measure the overall length of the assembled intermediate shaft. I get repeatable results with this method. I also used a digital caliper to measure overall length ,but found the results to be too varied to fully trust. ​
    [​IMG] [​IMG]
    #43
  4. richc

    richc Long timer

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    Great post! Thanks for taking the time to take and post those pics.
    #44
  5. johnjen

    johnjen I've Been Resigned

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    Excellent...

    I'm curious to see what you come up with for measuring the inside of the case...

    JJ
    #45
  6. bemiiten

    bemiiten League of Adventures

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    The intermediate shaft was placed in the freezer while I heated a 1" set collar on top a kerosene heater. The manual shows pulling the bearing with a puller, but I decided to do the removal with a press instead. I removed the frozen shaft and placed it on top of the heated set collar to warm the bearing for a few minuets. I installed the bearing clamp and put the assembly in the press. The clearance between the gear and bearing is extremely tight. As soon as the bearing moved a little , the clamp was tightened to allow a better bite. The freezing and heating paid off when the bearing came off nicely without excessive force. [​IMG]
    #46
  7. bemiiten

    bemiiten League of Adventures

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    The original failed intermediate bearings are from Japan. The replacements are from Poland. (same part#) The original output shaft bearings are from England, the replacements are also from Poland. (updated part#) All the bearings new and old measure the exact same thickness with the exception of the failed bearing that is .001" bigger. EDIT-After a more accurate measurement with a dial gauge, The bearings were indeed the same size. The caliper is sensitive to hand pressure and I'm sure that's the .001 difference). If you recall , this is the same bearing that did not want to come out of the housing during disassembly. I believe the 100+ miles the bike was ridden with the failed bearing may have distorted it somehow. The bottom line is all the bearings seem to be made to very tight tolerances. To my thinking, this means I am replacing apples with apples and their should be no reason to re shim the shafts, right? [​IMG] [​IMG]
    #47
  8. bemiiten

    bemiiten League of Adventures

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    Wrong! After allowing the shaft to warm back up to room temperature, I'm showing a difference of about .007" shorter. The manual list a maximum difference of .002" :huh
    The manual gives no absolute overall dimension for the shafts, and no inside dimension for the trans case. Just a .002 figure that I assume is endplay. Without the factory jig ,I can only compare what I had to what I have now. ​
    Here is the procedure I used for installing the bearings. I start by using a washer to absolutely guarantee that no force is exerted on the outer race. ​
    [​IMG]
    I freeze the shaft and use a heat gun on the new bearings. When the bearings hit about 150 degrees, I carefully line up everything in the press. It is easy to feel when the bearing is fully seated.​
    [​IMG]
    #48
  9. bemiiten

    bemiiten League of Adventures

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    Next up is the output shaft. The bearings are removed along with the adjoining gears. [​IMG]
    I follow the same procedure as before and wind up with similar results. About .006 shorter overall.​
    This should read zero , the bearings are the same size. ??:huh ?? One step I failed to take was making sure the old bearings were pressed fully home. It's in the manual ,but I neglected this step. It's the only possibility I can think of. I'm very confident the bearings are the exact same size.​
    [​IMG]
    #49
  10. bemiiten

    bemiiten League of Adventures

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    Up last is the input shaft. Like before, A comparison of old and new bearings show them to be exactly the same.
    Old bearing​
    [​IMG]
    New bearing​
    [​IMG]
    #50
  11. bemiiten

    bemiiten League of Adventures

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    While inspecting the transmission engagement dogs on the other shafts, I could not help but be impressed at just how good the condition of these parts were. With the input shaft disassembled , The title of the thread comes back to haunt me one more time!
    This can't be good! :cry
    [​IMG]
    This is the Thrust block. Check out that nice crack on the left ear! I suppose it could be just a gouge, but it extends to far to be from some debris getting in between the mating surfaces. It is on the power side. Their is just no way this can go back in. :cry
    #51
  12. bemiiten

    bemiiten League of Adventures

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    After 55k and one spline lube at 35k, The input shaft splines look like they have some life left in them. [​IMG] [​IMG]
    The clutch disk splines look a bit worse​
    [​IMG]
    I decide that replacing just the disk will accelerate the wear on both parts with their mismatched matting surfaces, so it makes sense to replace both while the trans is apart.​
    #52
  13. bemiiten

    bemiiten League of Adventures

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    Their is allot of debate over the toughness of BMW's dry clutch. I don't abuse my clutch , nor do I hesitate to slip it as much as needed when the situation calls for it. Compared to a new disk , the friction material shows very little wear and in my case, would probably outlast the splines by a wide margin.
    Old disk​
    [​IMG]
    New disk​
    [​IMG]
    #53
  14. bemiiten

    bemiiten League of Adventures

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    Still waiting on one last part. I figured I would post some pic's of the failed transmission shaft bearing.
    Left one is the culprit. You can see that the sealed bearing is out of it's lubricant. The seal shows metal shavings from the failure. Middle one is same (made in japan) bearing as left, also looking like it has some shavings and not much of whatever it is they pack these with. I do see what looks like ,the red trans fluid on the bearing cage. Maybe the synthetic penetrates the seal and dilutes the grease? The last on right is a output shaft bearing made in England. Looks like it has much more lubricant left then the other two.​
    [​IMG]
    #54
  15. Poolside

    Poolside Syndicated

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    <BR>This is a great photo writeup :thumb I missed it until just now. Very nice as a late unopened Xmas present.

    - Jim<BR><BR>
    #55
  16. PaleHearse

    PaleHearse Road Ranger

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    Looking forward to the punchline. Great work!

    Photos of the finished trans would be very cool!
    #56
  17. Poolside

    Poolside Syndicated

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    <BR> +1 Great work

    (And look at all those effective Harbor Freight tools. hyd press, dial gauge, mag base, caliper)

    - Jim<BR><BR>
    #57
  18. bemiiten

    bemiiten League of Adventures

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    I have had great luck with HF tools. The day I pick to assemble the trans , the brand new HF laser temp gauge crapped out. Then when I re borrowed the one pictured before, The brand new $10 heat gun went up in smoke mid job. :huh Lucky I had two. Both were replaced by HF inc. shipping both ways.
    #58
  19. bemiiten

    bemiiten League of Adventures

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    I noticed this little bite out of one of locating pin bores. The trans housing precludes setting your drift for a straight shot. Had to use a smaller 3/16 drift at a angle and it resulted in this. BMW must have a offset drift for this as I recall it didn't make sense to drive the pin from the opposite side. Anyway this picture is after I removed a small aluminum burr.
    [​IMG]
    #59
  20. AntonLargiader

    AntonLargiader Long timer

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    and
    I guess I'm late to this party, sorry.

    Don't assume anything is shimmed right. Every 6-speed I've worked on is loose somewhere. The manual I have does give shaft lengths but that doesn't mean much; I always check them the old-fashioned way (shaft protrusion vs. cover depth). I've measured a bunch of cases and covers and have a decent idea of what they should be. They're generally repeatable within about 0.05mm.

    Again, none of the numbers mean anything. Measure your parts as if it were an Airhead tranny.
    #60