Tony
Is it just a sound you are hearing or a vibration too? I'm getting a vibration and sound at low speeds almost not noticeable at higher (maybe cause the car makes more noise and vibrations at higher speeds).
I just had my driveshaft shortened and new CSB put in. I didn't however have the rubber replaced. Going to take it to a shop to diagnose it. I had the car on jackstands fired it up and didn't hear it or feel it, only when it's under load it seems. The vibrations feel like they are coming from the right side of the trans, which I'm not sure it's right or not.
Member
Hmm no vibration here from what I can tell...was just hoping to not have to invest a lot of money in this car already :/ inevitable I suppose...happiness tax? lolOriginally Posted by jajou318
Member
I'm happy with what I did. Peace of mind is worth a few 5/16 inch grade 8 bolts and grade 8 washers (on top and bottom). Welds are weak by nature. The heat hardens the metal around the weld so it's subject to crack around the welds. The bolts are much stronger than a weld because of the hardened metal, Grasshopper.
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No more clunk or thud from the rear or what I thought was excessive gear lash in the differential. The transmission has been rebuilt. The round rubber drive-shaft disc, carrier bearing, and differential mount has been changed and I added braces to the differential.
https://www.facebook.com/photo.php?f...type=3&theater
https://www.facebook.com/photo.php?f...type=3&theater
The sway bar I used to make the horizontal brace was 0.67 inch in diameter. I should have use a larger one but not over 1 inch, I guess.
Last edited by DuWop; 07-08-2013 at 09:36 AM.
B!tch Moan Whine
Interesting.
Would still rather do the dual ear conversion, but for $22 in material, not bad.
Last edited by Flak; 07-07-2013 at 03:11 PM.
Member
What went into the rebuild of your tranny? I was thinking about doing mine after I'm done with my engine build but haven't looked into details yet
Member
Change the torque converter, clutch disc and solenoids. My tran has 125 K miles on it and the clutch disc were not worn out. Not much trash in the fluid pans either. I can't find a spec on the disc or I could measure the wear. I don't think it's much. Some disc still had writing on the face. I believe the big problem with my tran was the 2nd to 3rd shift solenoid and maybe the torque converter clutch locking solenoid.
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The way I made this brace allows me to continue to carry my spare on the rack under the car instead of in the trunk as necessary when one installs the (mickey mouse ears) differential cover with two mounts.
The mouse ears type mounts would give much needed lateral bracing where as I'll have to install one more brace/mount for lateral bracing, that is if I bother to do it. I think what I have done so far is enough to prevent the differential from ripping it's self from the car. I think the clunking and thuds I was hearing was the differential ripping out the cross-member, caused primarily by a worn out differential mount and somewhat by worn out sub-frame mounts. Oh god, I dread changing them. I can put that off till next year I hope.
Last edited by DuWop; 07-08-2013 at 08:02 AM.
Member
I don't know for sure but I'm thinking there may be room for Mickey's ears and the spare tire rack if the bracket where the rack is hinged is replaced with some small stainless steel cables. I'll take a look next time I'm under there.
Member
The persons of the opinion that the drive shaft has to be removed for evaluation other that complete failures are correct. The drive shaft looked perfect. Even the Safety Inspection Mechanic said it looked good. I did some investigation on my 1997 Z3 clunker, and upon removal found that the differential u-joint was very stiff and locking somewhere but not quite in the middle of the rotational position. I did notice that the driveline is fairly straight so the joint doesn't move much from center and wears there. If it gets dry as in my case, it tends to lock there.
When under moderate acceleration, the joint and CSB accomodates this and you feel moderate vibrations slightly above normal until you shift into higher gear or decelerate and the shaft spins faster and self centers. Under high load, the differential u-joint will lock sometimes uncentered and cause the driveshaft to bounce back and forth inside the CSB causing a very loud banging. I observed this in the rubber ring around CSB as if something was beating the rubber to death, hence the need for a new CSB as well.
Last edited by inthe0zone; 08-10-2014 at 11:20 AM.
Member
a few thoughts
I've had many old/ hi mileage bimmers. driveshaft U-joints seem to last 175,00 miles. Driveline Service of Atlanta, among others, will replace these "unreplaceable" u-joints and balance the assy as part of their rebuild.
nearly EVERY driveshaft I've removed was not previously assembled with regard to the punch marks on each half of the splined assy. the front and rear u-joint "crosses" MUST be phased the same. Since simple u-joints speed up and slow down every 180 degrees of rotation (proportional to the angle between the input and output shaft of each u-joint), the rear half of the driveshaft oscillates in speed relative to the front half. (compare this to "CV" joints...constant velocity...) When the crosses are phased, the speed at the transmission end is identical to the speed at the input to the diff, IF the angles of both u-joints are equal. [engine/trans swappers often miss this point, then endlessly hunt down the "out of balance" driveshaft. ] So, unphased driveshafts vibrate (and have a favorite resonance frequency) , and over work the CSB, causing it to fail prematurely.
Balancing the driveshaft involves adding weight on the light side (as with tires) while spinning, INDEPENDENTLY of phasing. Hence, the punch marks show proper phasing and balancing alignment of the front and rear halves of the driveshaft. you should be able to find the marks with the driveshaft in the car.
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