[HaneifK]

[SOLVED] Driveline issues - STUMPED any help would be appreciated.

Hi guys, I've had one or two driveline problems for the last month that I've chased and chased, and now I'm stuck and my wits end trying to diagnose this thing. :banghead:

Any help/input would be much appreciated.

So about a month ago, my 2004 325i wagon (auto) started to develop a shudder during initial acceleration under load (from a stop). If i eased into the pedal it was fine, but if I accelerated normally, the rear end would shudder pretty hard. Got under the car to find the bearing on the csb was completely separated from the metal band so I changed the csb, guibo, and centering sleeve on the drive shaft, and the problem seemed to be almost completely gone. there was still, however a very slight shudder.

^Around this time I also had the rear wheel-bearings replaced

two weeks ago, the car started to develop a droning/vibrating sound when coasting, if I got up to 55+ mph and let off the gas, the vibration would get louder and louder until it felt like the car was driving on rumble strips around 30-45mph, below 30 it got quieter and above 45 it was quieter but the vibration never really goes away unless i'm on the gas pedal. If i'm half-way on the gas, the vibration diminishes but is never completely gone unless i'm 60% or more on the gas.

So i got back under the car, this time noticed the half shafts had ruptured and sprayed grease all over the inside of the wheel hub. I replaced the half-shafts but the problem is still there, and the shudder that used to happen under load from a stop seems to have returned.

Changed trans fluid, changed rear diff fluid. Problem still the same.
Both fluids seamed fine, no metal shavings or terribly black fluid or anything.

Also checked to see if brakes are dragging and they are not. (coasted to a stop touched rotors, none of them were warm/hot.)

I got back under the car, attempting to diagnose the U-joints, there is almost no rotation-play in the driveline if the car is in park, and absolutely no play if i'm trying to push/pull the driveline fore/aft near the U-joints. Doing some more reseach I did realize two things:

I re-used the guibo bolts, but they still seem tight. There is no play in the guibo.
I did not however, mark the position of the old CSB before i put the new one on (but i did mark the drive shaft).

I did notice the transmission mounts are shot.

So my question now is... could the vibration be the rear differential going bad? And why did the shudder under load come back?

I'm out of ideas and now turn to the community for help. Any input or feedback is extremely appreciated, thank you for reading.

 

[jcase]

Don't know if this will relate to your issue or not because I did not have a deceleration issue with it...
On my 02 330CI I replaced the guibo because it was just cracking. After that I got a bad vibration on heavy acceleration between 25-35 mph.
Tried a few things no help.
Then out of desperation of not wanting to replace the driveshafts CV joint I just moved the center bearing back 1/4 -1/2 inch.
I tried this because when I had the shaft out and on a bench I noticed if I while moving the CV joint I pushed it in a little it was a lot smother.
Long story short, no more vibration and it's been about 7,000 miles.

I'm thinking that the CV joint, after 180,000 miles, had worn slightly to a certain depth and just liked it there.

 

[HaneifK]

So you moved the center support bearing towards the rear of the car by 1/4"?

 

[pack horse]

The correct way to install the centre bearing bracket is to slide it forward to remove all free play then move it forwards a further 1/4" and torque down the bolts.

Have you installed the guibo with the arrows pointing away from the bolt heads? BMW recommend new bolts but I cant see using the old ones would cause vibration.

If the transmission mounts are shot I would replace them and check your engine mounts too.

While your under the car check the diff mounting bushings for play especially the large rear one.

 

[HaneifK]

I didn't know that about the CSB, thank you for the info. i'll have to try that this week!

When I inspected the guibo originally all the bolts were facing the same way (factory guibo) so I replaced the bolts all facing the same way (heads facing rear of car), but made sure the arrows on the guibo are pointing towards the flange arms.


I'll also check the diff mounting bushing, thanks for your help!

 

[Fast Bob]

For the record:

"Guido": (pron. Gwee-Doh) Gen. Tannus Maximus, typically found at the Jersey Shore

"Giubo": (pron. Jew-Boh) AKA/ "Flex Disc", commonly found on BMWs

 

[pack horse]

Rubber Coupling , that's a better name lol

 

[jcase]

For the record:

"Guido": (pron. Gwee-Doh) Gen. Tannus Maximus, typically found at the Jersey Shore

"Giubo": (pron. Jew-Boh) AKA/ "Flex Disc", commonly found on BMWs

:thumbup::rofl:

 

[HaneifK]

Lol, very informative Fast Bob.

Pack horse, I reinstalled the csb the way you mentioned and now the shudder under acceleration is completely gone!! Thank you!!!

I checked the diff mounting bushings and there's no play, nor is there any play in the u-joints. But the vibration when coasting has not changed.

I noticed the rear half shafts went bad around the same time the coasting issue started. I replaced them but nothing changed. Not sure if there is a specific procedure to replacing them? Maybe I missed something? Don't know where else to look at this point.

Also the tires are brand new but not BMW recommended... Any way that is the issue? The noise happened months after getting new tires tho.

 

[Fast Bob]

Whenever you are disassembling the driveline, you should employ some masking tape and a Sharpie pen, and create witness marks where things match up, to make sure everything is in proper alignment upon reassembly.

 

[HaneifK]

So there was vibration on initial acceleration but none when coasting. I replaced flex disc, centering sleeve and carrier bearing and I made markings for the driveline but not for the carrier bearing, however after reassembly, there was no vibration on coasting or acceleration. After a month or so a vibration when coasting developed. Took a look under the car and saw the halfshafts (rwd) were shot. Replaced them but no change in coasting vibration.

 

[pack horse]

Check the engine mounts and change those shot transmission mounts.

 

[HaneifK]

Changed the trans mounts... no dice. Finally took it to a shop today, got under the lift, and had another guy press the gas annnnnnd :drumroll:
Both (brand new, not reman.) half-shafts are out of round!
So, I called the store and they're going to replace them.

Hopefully that's it!

 

[pack horse]

Lets hope they are not from a bad batch!

 

[moots]

Changed the trans mounts... no dice. Finally took it to a shop today, got under the lift, and had another guy press the gas annnnnnd :drumroll:
Both (brand new, not reman.) half-shafts are out of round!
So, I called the store and they're going to replace them.

Hopefully that's it!

Half shafts are out of round meaning the shaft that connects both the outer and inner cv joints are bent?and they are brand new?

 

[HaneifK]

So the mechanic that put it up on a lift said they looked out of round, not sure if that was because the suspension was completely unsprung when the car was on a lift or what, but had to replace them again anyway because one side didn't even have the ABS ring. It still didn't fix the issue though...

SOOOOO

Finally I decided to take out the entire drive shaft and inspect it... turns out the U-Joint that bolts on to the diff was completely frozen on one axis. Bought a driveshaft from a salvage yard for $50, replaced it, and voila!!! The car drives sooooo smooth now, I forgot how damn quiet and smooth the ride was haha.

Thanks everyone for all the help and feedback!