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Discussion Starter #1
Well, I got another call from the SA today letting me know that the problem isn't the clutch, but rather that the drive shaft is somehow "separating from the differential...hence no lockup and total loss of power". hmmmhmmmhmmmhmmm

They plan on opening up the diff tomorrow to see what's going on, and what part(s) failed and then they'll let me know what comes next.

I called my independent shop to run this by the head guy, and he thinks this is BS...and is probably due to the fact that the driveshaft wasn't bolted on correctly, and the whole clutch job may have been botched to begin with. :confused2

Anyone have any thoughts on this? I know our drive shaft is bolted onto the diff with 4-5 relatively large bolts which should not shear, break or separate with normal use...especially after only 30K miles!!

More importantly, should I be concerned that there may be a problem with the clutch/trans secondary to the diff-drive shaft problem...or whatever the he!! they're calling it? :grrrrr:

How strongly can I push to have this taken care of by BMW given that the car is outside the factory warranty period?
 

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This sounds really strange. I'd wait for more information as they dig deeper. But I think you are right to be questioning everthing.
 

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i thought the original problem was the trans got stuck in gear, right? how does a diff problem cause that..... smells like.....
Mike
 

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Discussion Starter #4
Mottati - the original problem was clutch, then when they changed it, it was tough to get the trans into 1-2-R...so I brought it back and they bled the clutch reservoir. This supposedly "fixed" the problem for a few hours...but later on that evening, the clutch failed again after 60 miles...now they're telling me the problem's not the clutch but where the drive shaft meets the diff...I've asked for a schematic with specifics and will ask that a BMW rep look at it to determine exactly what the hell is going on...I'll add more info to the post when I hear back from them later on today.
Thanks guys.

LS

mottati said:
i thought the original problem was the trans got stuck in gear, right? how does a diff problem cause that..... smells like.....
Mike
 

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Hey, anything is possible, it is often hard to tell about a problem from a keyboard. However, my confidence level is this dealership would not be very high.

Even if they forgot to bleed the clutch (didn't know the hydraulic system had to be opened to replace the hardware), which is error #1, they didn't even bother to road test the car after replacing the clutch?? Error #2. And if they did, they didn't feel how difficult the gear box was to shift? Error #2a. While the car is on the lift, most mechanics will look to make sure everything is tight and suspension looks good. Loose diff bolts?? Unlikely, but if so, they missed that. Error #3. Flex disc? Possibly, takes 15 seconds to inspect. Error #3a.

Hard shifting is either tranny linkage out of adjustment, or clutch not properly disengaging (for a variety of reasons). After the diagnosis is made but before the covered repairs are made, I would have a discussion with the SA and the Service Manager about the skills of your tech. On a "bring back", typically it will be the same technician to redo the work. I think you want someone else and you want to know that tech's experience with cars in general, and M cars in particular. My $.02 (at least!!). :cheers:
Regards,
Jerry
 

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(didn't know the hydraulic system had to be opened to replace the hardware)
I agree with Jerry. As for the quoted comment, I think it does have to be opened up because the slave cylinder is on the transmission case, and the case has to be pulled to change the clutch.
 

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ISDVM,
Having just replaced my clutch, and only going by what you have written, I would offer these thoughts. To remove the tranny the driveshaft must be partially removed. Three large bolts at the tranny (guibo) and two bolts at the center bearing (in b/n the tranny and diff. The driveshaft connects to the diff via a cv joint like a front wheel drive car half shaft. You must support the driveshaft when it is unbolted in order to avoid damaging the cv joint. Also, during installation, the center bearing must be properly aligned to keep the driveshaft running true, if not it could wearout the center bearing and cause the driveshaft to wobble, usually a banging noise like a bad u joint. If the cv joint failed, which is where the driveshaft enters the diff, my guess is it was from not supporting it properly during tranny removal. The BMW manual is very explicit about this. FWIW, older bmw's used to require a preload on the center bearing during installation, they dont anymore. It is possible to bolt the center bearing in upsidedown, but I dont think you can get the heat shields on over it. Just some food for thought. If it were me I would want to look at the car closely on the rack as the disassembled it. Sounds to me like something wasnt done right, like tightening the center bearing bolts or not supporting the driveshaft.

ernest
 

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Discussion Starter #8
Re: Drive shaft and diff out of sync??

Emccallum - thanks for the technical advice. My gut tells me something wasn't done right the first time around...hence my predicament. I received a call from the SA today, and he indicated that they have to order a new part (where drive shaft enters diff)...which will bein tomorrow and hopefully everything will be fine from there.

He mentioned something else which I thought was completely odd...that the drive-shaft was engaging-disengaging from the diff just by being jolted. Is this even possible?? I thought these things were tightly bound together by bolts and casing??

I've asked for the schematic of what failed, but they're hesistant to fax it to me. I'll have to wait until Sat AM to go and see this whole fiasco for myself.

I wish someone would just come out and say they screwed up...guess that's too much to ask these days?? Such a shame.


emccallum said:
ISDVM,
Having just replaced my clutch, and only going by what you have written, I would offer these thoughts. To remove the tranny the driveshaft must be partially removed. Three large bolts at the tranny (guibo) and two bolts at the center bearing (in b/n the tranny and diff. The driveshaft connects to the diff via a cv joint like a front wheel drive car half shaft. You must support the driveshaft when it is unbolted in order to avoid damaging the cv joint. Also, during installation, the center bearing must be properly aligned to keep the driveshaft running true, if not it could wearout the center bearing and cause the driveshaft to wobble, usually a banging noise like a bad u joint. If the cv joint failed, which is where the driveshaft enters the diff, my guess is it was from not supporting it properly during tranny removal. The BMW manual is very explicit about this. FWIW, older bmw's used to require a preload on the center bearing during installation, they dont anymore. It is possible to bolt the center bearing in upsidedown, but I dont think you can get the heat shields on over it. Just some food for thought. If it were me I would want to look at the car closely on the rack as the disassembled it. Sounds to me like something wasnt done right, like tightening the center bearing bolts or not supporting the driveshaft.

ernest
 

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Re: Drive shaft and diff out of sync??

Cant speak for the tech. But it doesnt sound good. Are you getting a new driveshaft, has the center bearing been damaged? You can go to realoembmw.com (I think that is right) and they have the parts cd online that will show you how it all fits together. If they are footing the bill, then be nice and insist it is right, if you are footing the bill ask for all the parts, so you can see what is going on. You are buying the ticket ask to see the show! Best of luck.

lsdvm said:
Emccallum - thanks for the technical advice. My gut tells me something wasn't done right the first time around...hence my predicament. I received a call from the SA today, and he indicated that they have to order a new part (where drive shaft enters diff)...which will bein tomorrow and hopefully everything will be fine from there.

He mentioned something else which I thought was completely odd...that the drive-shaft was engaging-disengaging from the diff just by being jolted. Is this even possible?? I thought these things were tightly bound together by bolts and casing??

I've asked for the schematic of what failed, but they're hesistant to fax it to me. I'll have to wait until Sat AM to go and see this whole fiasco for myself.

I wish someone would just come out and say they screwed up...guess that's too much to ask these days?? Such a shame.
 

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Re: Drive shaft and diff out of sync??

emccallum said:
Cant speak for the tech. But it doesnt sound good. Are you getting a new driveshaft, has the center bearing been damaged? You can go to realoembmw.com (I think that is right) and they have the parts cd online that will show you how it all fits together. If they are footing the bill, then be nice and insist it is right, if you are footing the bill ask for all the parts, so you can see what is going on. You are buying the ticket ask to see the show! Best of luck.
www.realoem.com/bmw

or

http://www.realoem.com/bmw/select.do

close...

:)

A
 
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