325iX Vibration - Parts Question

[tonight, we ride]

Hey guys!

I've got a 1990 325iX that I picked up about 2 months ago, and am just now getting around to placing an order for parts to try to eliminate a vibration that is present at specific speeds. The vibration occurs around 30 MPH, and then again around 70 MPH, and is only severe enough to cause the driver side mirror to noticebly vibrate (but not the passenger side). It is not dependent on RPM, does not whine or change pitche when cornering (I honestly don't think it's the wheel-bearing, but figure it would be good to change it regardless), and 90% of the time is only present when pressing the accelerator pedal while in gear (putting the car in neutral, or releasing the gas pedal while elimate the vibration MOST of the time).

The PO said that the left rear-wheel bearing was replaced, and that he suspected the right rear-wheel bearing as the culprit, but after reading up on other people's similar issues I'm thinking it could also be the flex-disc (guibo) going out, or some other driveshaft related issue. I decided i'm just going to flex the credit card a bit and order both parts and, from what I've read, it seemed like a good idea to change out the CSB at the same time.

However, while putting together a parts order over at PelicanParts.com I noticed that none of their options for the CSB seem to be listed as compatible with the 325iX... and now I'm questioning whether there IS a CSB on the iX.

If any of you iX gurus have any input I'd appreciate it. Here's what I was planning on ordering, but let me know if there's anything else that is worth changing out simultaneously:

Rear Wheel Bearing Replacement Kit Part #PEL-E30RWBKT-02N

http://www.pelicanparts.com/catalog/SuperCat/0240/BMW_0240_SUSAXL_pg5.htm#

Flex Disc For Driveshaft (Manual) Part #26-11-7-511-454-

http://www.pelicanparts.com/catalog/SuperCat/0240/BMW_0240_SUSAXL_pg3.htm#item9

Is it worth it to change out the Transmission Mounts while I'm down there? Should I replace the 5 bolts on the Flex-Disc as well? IS there a CSB on the iX? Any input is appreciated!

Thanks!

[spdracrm3]

yup no CSB on an IX as its a one piece driveshaft due to the longer Trans/T-case combo.

there are three guibo's (front and rear driveshaft and one between t-case and trans), you could also have a bad rear driveshaft u-joint or front C/V joint going bad

[tonight, we ride]

Thanks! That makes much more sense than having the CSB... I was scratching my head over how that would have worked. But I am garageless and haven't had a dry day in weeks to climb under the car (the sun decided to come out today though!).

Is it safe to assume that the 3 Guibos are all the same, in regard to part #?

I'll probably go ahead and change out the 3 of those, as well as the wheel bearing. If that doesn't eliminate the issue I'll look into the driveshaft u-joint and front C/V joint. Thanks for the heads up about those!

*edited to say, I just saw you're in Renton... I'm up in Bellingham, so I guess you have a pretty good idea about what the weather has been like!

[tonight, we ride]

I just was plugging in some part numbers from RealOEM.com to check out cost on the hardware for the guibos, and Pelican Parts is charging $47 for the 6 M10 bolts/washers/nuts associated with the Guibo... WTF??

Is there any reason I can't just go down to my local hardware store and pick up the same size bolts/washers/nuts for about $5? This just seems insane to me. They're charging more for the hardware than the actual Guibo.

Anyone that's done this repair have any insight?

[spdracrm3]

I just was plugging in some part numbers from RealOEM.com to check out cost on the hardware for the guibos, and Pelican Parts is charging $47 for the 6 M10 bolts/washers/nuts associated with the Guibo... WTF??

Is there any reason I can't just go down to my local hardware store and pick up the same size bolts/washers/nuts for about $5? This just seems insane to me. They're charging more for the hardware than the actual Guibo.

Anyone that's done this repair have any insight?

ive never changed the nuts or bolts (chances are they wont be the right diameter @ the shoulder part if you buy generic), if your worried just apply some blue loctite to the threads (there is usually sufficient self locking on the nuts for multiple uses anyway) and torque to spec

Thanks! That makes much more sense than having the CSB... I was scratching my head over how that would have worked. But I am garageless and haven't had a dry day in weeks to climb under the car (the sun decided to come out today though!).

Is it safe to assume that the 3 Guibos are all the same, in regard to part #?

I'll probably go ahead and change out the 3 of those, as well as the wheel bearing. If that doesn't eliminate the issue I'll look into the driveshaft u-joint and front C/V joint. Thanks for the heads up about those!

*edited to say, I just saw you're in Renton... I'm up in Bellingham, so I guess you have a pretty good idea about what the weather has been like!

no i think every guibo part number is different unfortunately , and to do the guibo between the Tcase and trans you will have to drop the T-case out ( if you have loose sloppy shifter now is the time for a rebuild, and check/repair oil leaks), you will have the rear driveshaft out to do the guibo on it so thats the time to check the U-joint . Also you will have front driveshaft out so can inspect/lube the splines and if necessary spacer the driveshaft if splines are going bad

yes nice day in Renton today ,rode the 2 wheeler to worky

[EyExR]

Are your tires good? Tie rod ends okay? Control Arm Bushings?

Usually a bad wheel bearing would present itself as a loud "whirring" sound.

...so many things can cause a car to shimmy at speed...

[tonight, we ride]

...so many things can cause a car to shimmy at speed...

Yeah... that's what makes this problem so hard to address!

I just got new tires, and they were put onto a set of original weaves that were a little beat up, but I had professionally straightened/refinished, so that shouldn't be the issue.

I'm going to order the three Guibos and a right-rear wheel bearing this week to eliminate those as causes. There is a slight whirring sound that I can hear when starting from a full stop, but it's not loud enough to hear when the car is moving above ~15 MPH, so it could still be the wheel bearing... But it disappears so quickly, and I haven't noticed any changes when cornering, that I am not ruling out other potential causes.

I will probably post part numbers/diagrams from RealOEM tonight to double check that I am ordering the correct parts for the guibos. I'm trying to do all the work on this one myself, but am still learning the details of this driveline. Thanks again for your responses, I'm looking forward to getting this straightened out!

*Edited to say that it looks like control arm bushings are fairly cheap. May as well check mine out tonight, along with the tie-rod ends, to see if there's anything else I should order. Any recommendations of other ares in the suspension to check out while I'm down there?

[EyExR]

get M3 offset CAB bushings if yours are worn...

[tonight, we ride]

Thanks for the heads up! I'm assuming I would just go with the OEM part for a '90 M3... Any input about whether these ones would fit in the '90 325iX, or is it worth it to just get some of the ones from http://www.condorspeedshop.com/?

Part #31-12-9-061-222-M69

http://www.pelicanparts.com/cgi-bin/ksearch/pel_search_2014.cgi?SUPERCAT_FLAG=Y&make=BMW&please_wait=N&LastVisited_input=0545&Previous_Section=SUSSHK&forumid=&threadid=&command=DWsearch&description=31-12-9-061-222-M737&I1.x=0&I1.y=0

I've never done CABs before but everything I'm reading makes it sound like a pain in the ass to change them out.

[EyExR]

I actually just purchased the Condor ones. I'll let you know how they feel. ...although my summer wheels are tramlining like bitches...

[ghatid]

Is it worth it to change out the Transmission Mounts while I'm down there?

Did you decide to change the transmission mounts? I'm wondering if anyone knows what part number they are. Pelican parts wants $35.50 each, but I would love to know if there are other options.

[The Dark Side of Will]

Assuming your car is a stick, as the automatics don't have a guibo between the trans and T-case.
No reason to replace the bolts. Just get the torque spec right.

The u-joint at the rear end of your rear driveshaft could be worn also.

[tonight, we ride]

Did you decide to change the transmission mounts? I'm wondering if anyone knows what part number they are. Pelican parts wants $35.50 each, but I would love to know if there are other options.

I actually haven't had a chance to change anything out yet. I did get under there last Friday in order to do a coolant change, and was able to inspect the control arm bushings and one of the guibos... nothing was out of place, so it's either got to be one of the other two guibos or the U-Joint.

Here's a recap of the symptoms in case anyone has further suggestions:
-Vibration occurs at ~30 MPH and then again between ~50-60 MPH
-Vibration only occurs at those speeds when foot is on the accelerator pedal
-Vibration disappears completely at said speeds if foot is taken off pedal and transmission is in gear
-Vibration remains at said speeds if foot is taken off pedal, but transmission is placed in Neutral (yes, it's a manual transmission).
-Vibration is ONLY speed dependent, not RPM dependent (which is causing me to want to rule out a muffler issue)

I'm scratching my head over this one, so any help or insight is appreciated!!

[The Dark Side of Will]

Have you had the tires balanced?
Tires that have been balanced new and then worn slightly differently can cause weird effects.

Is it wheel speed? Driveshaft speed?
Assuming it's the same in different gears, also.

[tonight, we ride]

Had new wheels and tires put on the car and the problem is still there... didn't do an alignment, but the problem was present both before and after the wheel/tire swap.

I haven't had it on a lift to check if it's consistent with driveshaft speed only, I'm basing all of my info off of Wheel-Speed when driving under normal conditions.

Doesn't seem to make a difference what gear I am in. If I shift gears at one of the problematic speeds there is no change between the gears.