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  1. #1
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    91 M5. Hard to shift and grinning noise.

    I have 91 M5 160K. Just got it. Runs good, but shifts hard. Goes ease in gears if you pump clutch 2 times. Plus I can hear grinning noise and if I press clutch down it goes away. When I let go it appears again. I think, master cylinder, slave cylinder right?
    Any other suggestions would be appreciated.


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    Alec
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    Are there any intelligentM5owners here ore onlyBS?


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    Re: 91 M5. Hard to shift and grinning noise.

    The noise you hear with the clutch out in neutral is the normal gear rattle of the Getrag 280 gear box.
    I assume the hard to shift occurs when the going from neutral to first from a stand-still and some gear clashing between gears during fast shifts? Try engaging second gear then first when starting off.

    These transmissions were designed for Dextron ATF; period. Other gear lubes such as a synthetic MTL will interfere with sychro performance. Ive been-there-done-that.
    I own a 91M5 and 88M6 and they both exhibited sychro problems when I changed to synthetic MTL and the problems stopped when I switched back to ATF.

    You will want to drain the gear lube and replace it with Dextron ATF at least 2 times (change to ATF, drive the car 25-50 miles and change the lube the second time) to effectively flush out the gear lube that is currently in the transmission. Then re-evaluate the synchro performance.

    Testing for sychro performance and clutch drag:
    1) With the engine off and clutch depressed the shift lever should move freely through the gears. If not; the transmission may have an internal shift linkage problem. There are also some external shift linkage bushings that should be checked or replaced to tightened up the shift linkage.
    2) With the engine running, transmission in neutral and clutch out push the gear-shift toward each gear and there should be no gear clashing observed.
    3) With the engine running and the clutch depressed the gear-shift lever should move freely through the gears.
    4) If the gear-shift lever does not freely move into a gear with the clutch pedal depressed apply pressure toward engagement and hold the pressure while turning the engine off.
    a) If the gear-shift slip into gear then the clutch is dragging when disengaged - preventing the sychro from stopping the spinning gear cluster and preventing gear engagement. Replace clutch and pilot bearing.
    b) If the gear-shift does not slip into gear then the transmission most likely has an internal gear-shift linkage problem. (I assume the external gear-shift linkage bushings have been inspected/replaced and confirmed good.)
    Rod...
    BMWCCA GGC

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    For better response go to:


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    your transmission syncros are probably worn

    Sounds to me like your clutch is working ok but the syncros in the transmission are worn. Those little buggers are there to match the speed of the input and output shafts while shifting...to avoid that grinding noise. That is whay double clutching helps. The problem is usually most noticable in the 1 to 2 shift and or the 2 to 3 shifts.

    If you can double clutch downshift 3 to 2 without noise and when you do it the usual way it grinds then the syncros are toast...

    guido

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    Could also be bad throwout bearing.

    The noise may be form worn clutch throwout bearing. Did you research the maintenance history? If the clutch is old, the pressure plate may be weak and cause incomplete engagement. Best to take it to a reputable BMW shop for proper diagnosis.

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    Re: Are there any intelligentM5owners here ore onl

    join http://autos.groups.yahoo.com/group/bmwe34m5/ to avoid the BS on this site....oh I suppose it's not all BS, but there's a lot more knowledge at the yahoo group. many of us cruise both sites, but now that you own an E34 M5 that's where you belong. you'll find much better advice faster over there.

    Eric Lee
    91 M5

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