328xi Shakes When Accelerating

[mbjg0788]

I own a 2008 BMW 328xi. When I accelerate, the vehicle shakes, especially when the tachometer is between 1500 and 2000.


I got under the car and shook the front driveshaft. When I did, I noticed there was what seemed to be an unreasonable amount of movement in the universal joint adjacent to the transfer case. I tightened all of the ZNS bolts holding the universal joint to the transfer case but this did not solve the problem. I am not sure what is the next step. Do I replace the ZNS bolts that hold the universal joint to the transfer case? Do I need to replace the front driveshaft? I hope not since I priced a new driveshaft at $520.


FYI I recently discovered that my cooling fan is not working. I ordered a new fan and will be installing the new fan when it arrives in a few days. I do not, however, believe that the lack of a cooling fan is causing the shaking.


Can I please have your thoughts, counsel and advice?


Thanks.
John

[Critter7r]

I feel like I answered this already, but I don't see my post ..... :shifty

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Replace the halfshafts, you can find them online for about $100 each.

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I still don't know what a ZNS bolt is.

[mbjg0788]

I feel like I answered this already, but I don't see my post ..... :shifty

- - - Updated - - -

Replace the halfshafts, you can find them online for about $100 each.

- - - Updated - - -

I still don't know what a ZNS bolt is.


Thank you for your response. Sorry you replied twice. That is my fault. I am new to this website. I posted in one forum then realized it was not the best forum for the posting and then reposted in the better forum.
In any event, I checked with Bavaauto on the web and it has the front driveshaft for $900.

I just checked the rules of this forum and there is no bar to one member giving the name of a vendor to another. I would really appreciate the information. Here is my email address if you would like to share it with me via that method: mbjg0788@gmail.com. BTW, ZNS bolts are the bolts that hold the universal joint to the transfer case on one end of the driveshaft and the universal joint to the front differential flange on the other end of the driveshaft.
Thanks.

[Critter7r]

i was speaking of Front HALFshafts, not DRIVEshafts. Reading comprehension apparently escapes me. But there should NOT be any play in the front driveshaft in ANY direction, so you'll need a new one of those. I haven't found a cheap one new either. A good used one from a wrecking yard might be the way to go.

bavauto.com was the site I was referring to

BTW, I gathered from your post what the purpose of ZNS bolts is, but not what the acronym means.

[mbjg0788]

Thank you for your response.

Am I correct that the half shafts you speak of are front axle half shafts?

When I saw the unreasonable movement, I was moving the half of the front driveshaft that is connected to the transfer case, and when I did move that part of that driveshaft I saw the unreasonable movement in the universal joint that attaches to the transfer case. Accordingly, do you think replacing the bolts that hold the front driveshaft, all eight of them, with new bolts and re-torquing them might solve the shaking problem I am having?

Thanks again for your help.

[Critter7r]

If those 8 bolts aren't loose, replacing them won't have any effect. If they are loose, I hope you've tightened them by now.

As long as the flange that bolts to the front differential and the flange that bolts to the transfer case are bolted tightly, there shouldn't be any play in that front driveshaft. If there is, then the U-joints are shot and the shaft needs to be replaced. Although, with enough searching, you could probably find a driveshaft shop that would replace JUST the U-joints, and it would probably be less expensive than replacing the shaft. But you would probably have to remove and install the shaft yourself and take only the shaft to the place that rebuilds them.