Still have shudder at 15mph after changed driveshaft help!

[sl600]

I had a driveline shudder at 20mph it was diagnosed as a bad driveshaft. Bought a brand new entire driveshaft from the BMW dealer and it was professionally installed and now I have a shudder at 15mph. Any idea what it could be? Mechanic said he preloaded and also made sure to align the arrows with the flanges of the transmission. I'm with the mechanic now anything else to check?

1997 850Ci 70K miles

[m6bigdog]

I had a driveline shudder at 20mph it was diagnosed as a bad driveshaft. Bought a brand new entire driveshaft from the BMW dealer and it was professionally installed and now I have a shudder at 15mph. Any idea what it could be? Mechanic said he preloaded and also made sure to align the arrows with the flanges of the transmission. I'm with the mechanic now anything else to check?

1997 850Ci 70K miles

Unfortunately a professional dealer or Indy mechanic may be a professional in the terms of employment, but they may not be able to repair an E31.
They never see them in there daily activities, just too rare!!
Could be engine, trans or diff mounts?


https://e31repair.com/en/index1.html
Section 26 Propeller Shaft Deflection Angles
Also: Bimmerforms discussions, diff vertical alignment...
https://www.bimmerforums.com/forum/s...haft+alignment
all the best,

[sl600]

Looks like the drive extension bearing which is behind the output flange in the transmission has developed excessive play causing a small leak from the seal and that play is causing the shudder. If you look at https://www.realoem.com/bmw/enUS/sho...diagId=24_1280 I need to replace the bearing in item #1 which comes as an entire unit part 24131422520

Does anyone have a guide or link to a video on replacement of this bearing? It is the complete assembly at 2:53 in this video, just want to know if it can be removed without removing the entire transmission https://youtu.be/FDLFcruXBKw?si=xxxk8sB1Eiv7lM6X&t=173

Engine and transmission mounts are new and were in good condition when replaced. Have not changed the differential mounts though but car has always been garaged and has 70K miles.

Transmission is 5HP30

[rjjablo]

Looks like it just unbolts.

I would replace the seal 2 and O-Ring while you are in there.

I know people have replaced the seal while the trans is in the car and while not the most fun is doable

Likely need to remove the trans mount to get the engine to tip to get enough clearance to get to the bolts just like removing the transmission

[sl600]

Some more information: the shudder is mostly noticeable going uphill or at any incline at 15mph and feels like it is coming from the rear. On a flat or downhill slope there is barely any shudder.

[cartoonz]

more likely the flange is not attached securely to the output shaft. That collar nut has to be tight. If not, the whole thing flops around.
The seal is easy enough to replace, but that bearing is definitely not. Fortunately, the bearing is most always not the problem.

Wait... car is a '97... the whole bit gets replaced.

[m6bigdog]

Drive line Laser alignment.
How it is done:
https://www.bimmerforums.com/forum/s...haft+alignment

[sl600]

My guess is that since the old driveshaft was faulty it, over time, caused damage in terms of radial play to the transmission output flange bearing which also caused the slight oil leak at the seal of the output flange. The reason I still have a vibration after replacing the driveshaft with a new BMW one, but at a lower speed and with a slightly different type of vibration is that the driveshaft is now aligned, balanced and working correctly but the transmission output bearing is still bad and has the same play as before, which is causing the vibration.

[sl600]

UPDATE: looks like the issue is with the differential. Mechanic turned the rear wheels while off the ground and there was a binding almost grinding sound. So he disconnected the CV and twisted the output shafts on the diff and they were binding. Any idea what could be wrong with the diff? Car has 70K miles. And does anyone know a good differential shop near Los Angeles?

[rjjablo]

My guess is that the Axle Shafts are eating themselves. Close inspection of the rubber boots for tears.

Also you can drain and refill the rear differential. Look for glitter and chunks coming out.

- - - Updated - - -

My guess is that the Axle Shafts are eating themselves. Close inspection of the rubber boots for tears.

Also you can drain and refill the rear differential. Look for glitter and chunks coming out.

[cartoonz]

So ...does anyone know a good differential shop near Los Angeles?

Hoopers Rear Ends... kid you not, worth the trip.
http://hoopersrearends.com/

[sl600]

Hoopers doesn't do BMW diffs anymore.

Hoopers Rear Ends... kid you not, worth the trip.
http://hoopersrearends.com/

- - - Updated - - -

I removed the CV axles and the differential binds even without them so is it safe to say it has to do with something inside the diff?

[rjjablo]

If you removed the Axles and the diff is binding you have something expensive wrong

If you have an automatic its time for a 3.94 with LSD

[sl600]

Yes it is bizarre because when I changed the diff oil there were no metal particles but the fluid did seem low without any sign of leakage. Color was also light gold so was not burned. From where do you recommend a 3.94 with LSD?

How can there be binding with no noise, just slight vibration which goes away after 15mph?

If you removed the Axles and the diff is binding you have something expensive wrong

If you have an automatic its time for a 3.94 with LSD

[cartoonz]

you could try Toy Shop Transmissions in Pomona too

But if you call Carl Nelson at La Jolla Independent, he might be able to point you in the right direction too.

[sl600]

Carl referred me to AVUS Autosport in Glendale, anyone have any experience with them? They're not an axle shop so I'm assuming they would farm this out anyway.

you could try Toy Shop Transmissions in Pomona too

But if you call Carl Nelson at La Jolla Independent, he might be able to point you in the right direction too.

[cartoonz]

If Carl sent you to them, go there.
He would not send you to a "farm out"

[sl600]

Okay spoke to AVUS they said they would farm it out and do the installation themselves but they do not rebuild or fix differentials themselves.

If Carl sent you to them, go there.
He would not send you to a "farm out"

[cartoonz]

Interesting... Carl is getting lazy? Did Andrew ( at Avus) tell you who they send them to?

[m6bigdog]

If you removed the Axles and the diff is binding you have something expensive wrong

If you have an automatic its time for a 3.94 with LSD

NO NO!
This is a 1997 850/M73 with 5-speed, not the M70 with 4-speed.
The 3.91 LSD would be a 1000 RPM jump to 3500 RPM's for 83 MPH in 5th gear...
A 850/M70 with 4-speed would at least be at 90MPH @ 3500 RPM.
The 4-speed M70 is 3000 RPM @ 83MPH with the 3.64:1 diff gears.
The 5-speed M73 would be 2900 RPM @ 83MPH with the 3.23:1 diff gearing.

I'm not saying others with the 5-speed have not done a 3.91:1 diff change!!
Personally, I would not go below 3.45:1 LSD.
3.23:1 LSD is more in the middle between 3.45 & 3.15 diff gearing, IMHO, with plenty of scoot, especially with the Sport Drive-TCM with 1st gear use in Sport mode.
Do some gearing calculation to verify the RPM/Speed changes with the optional diff gearing, before you leap into really low gearing..

[sl600]

What do you think is causing the binding. You would think if there is binding I would hear some sort of humm at higher speeds but it's just a vibration at 15mph then goes away with speed. Any diff shop you would recommend in LA?

NO NO!
This is a 1997 850/M73 with 5-speed, not the M70 with 4-speed.
The 3.91 LSD would be a 1000 RPM jump to 3500 RPM's for 83 MPH in 5th gear...
A 850/M70 with 4-speed would at least be at 90MPH @ 3500 RPM.
The 4-speed M70 is 3000 RPM @ 83MPH with the 3.64:1 diff gears.
The 5-speed M73 would be 2900 RPM @ 83MPH with the 3.23:1 diff gearing.

I'm not saying others with the 5-speed have not done a 3.91:1 diff change!!
Personally, I would not go below 3.45:1 LSD.
3.23:1 LSD is more in the middle between 3.45 & 3.15 diff gearing, IMHO, with plenty of scoot, especially with the Sport Drive-TCM with 1st gear use in Sport mode.
Do some gearing calculation to verify the RPM/Speed changes with the optional diff gearing, before you leap into really low gearing..

- - - Updated - - -

Avus said there was a shop they would send theirs too that is no longer in business and he had no other recommendations for a shop. I have heard good things about Ramjet in the valley.

Interesting... Carl is getting lazy? Did Andrew ( at Avus) tell you who they send them to?

[m6bigdog]

I do my own diffs - so no suggestions!

15 MPH is 3.4 Wheel revs/sec. or 3.4Hz vibration,
The drive line at 15 MPH is 2.8 x 3.4 = 10Hz vibration.
I would instrument the car to determine which vibration it is since you can't hear either one but one is the drive line induced and the other is at the wheel rotation rate.

I assume the drive-line CV was also disconnected when tested? Both output shaft CV's also?
That way you are only feeling the pinon & output flange bearings!!
Otherwise it could be the caused by the drag in the drive-line/Output shafts/wheel bearings, Brake Pad, etc...
Vibrations can go away; like drive-line center bearing or output shaft movement.
but unless you instrument the vibration you don't know where which side of the diff the vibration is on.

Are you sure that diff is the OE open diff and not a gear reduction LSD upgrade?
I don't care for how input flanges were swapped as this could cause too much pinion bearing preload, with an eventual bearing failure.
The M73/CSi Output Shaft & CV joints are NLA so keep your fingers crossed on that one!!

[sl600]

It looks to be the original open diff based on 1) real oem 2) the rear wheels spin in opposite directions when rotating one by hand 3) one owner elderly couple before me so doubt they upgraded it. I have attached a photo of it for you too. Drive line CV was not disconnected when tested just both output CVs.
IMG_5334.jpg

I do my own diffs - so no suggestions!

15 MPH is 3.4 Wheel revs/sec. or 3.4Hz vibration,
The drive line at 15 MPH is 2.8 x 3.4 = 10Hz vibration.
I would instrument the car to determine which vibration it is since you can't hear either one but one is the drive line induced and the other is at the wheel rotation rate.

I assume the drive-line CV was also disconnected when tested? Both output shaft CV's also?
That way you are only feeling the pinon & output flange bearings!!
Otherwise it could be the caused by the drag in the drive-line/Output shafts/wheel bearings, Brake Pad, etc...
Vibrations can go away; like drive-line center bearing or output shaft movement.
but unless you instrument the vibration you don't know where which side of the diff the vibration is on.

Are you sure that diff is the OE open diff and not a gear reduction LSD upgrade?
I don't care for how input flanges were swapped as this could cause too much pinion bearing preload, with an eventual bearing failure.
The M73/CSi Output Shaft & CV joints are NLA so keep your fingers crossed on that one!!

[m6bigdog]

It looks to be the original open diff based on 1) real oem 2) the rear wheels spin in opposite directions when rotating one by hand 3) one owner elderly couple before me so doubt they upgraded it. I have attached a photo of it for you too. Drive line CV was not disconnected when tested just both output CVs.
IMG_5334.jpg

RE: attached image - diff cover casting number, p/n: 33111213840.
RealOEM parts data is an assumption and may have little to do with the actual installed parts.
Validate final-drive gear ratios by counting the # of pinion flange turns, with 1 or 2 output flange turns.
As you said, an "Open" differential will have the output flanges turn in opposite directions with little to no resistance in rotation.

However, a clutch style LSD's also has spider gears just like the Open diff and when the clutches are warn out the axles can turn in opposite directions also
It is possible your diff has a bad output flange bearing, spider gears/bushings or bad LSD clutches.
When the drive-line does not turn, both output flange bearings, spider gears (LDS clutches) are all that rotate in the diff.
Bad LSD clutches tend to make a grinding sound when they are warn out.

"Elderly Couple"!!
Statement of age bias? What determines elderly? Now we know...

An Old Guy's Perspective:
A 1997, 850 is a 28 year old vehicle. (a classic & old for a car)
So, a couple of 80 years, with means, would have been 52 and not so elderly, when it was purchased new.
Couples that are 'not-in-need-of-employment' may like their Bimmer's with performance upgrades and tuned for long road trips!
Purchased mine 21 yrs ago, just before I was 'not-in-needed-of-employment'.
With that, older guy's can devoted their copious quantities of free time to all their hobbies.
FWIW, I have yet to stop upgrading any of my Bimmer's, to include the 850/M73, 21 yrs later.

[sl600]

But was an LSD even an option on a 1997 850Ci? I do not think so. If it was not an option, then it would have to have been something installed by the prior owners correct? Hardly can imagine them installing a LSD when literally everything else in the car is stock.

RE: attached image - diff cover casting number, p/n: 33111213840.
RealOEM parts data is an assumption and may have little to do with the actual installed parts.
Validate final-drive gear ratios by counting the # of pinion flange turns, with 1 or 2 output flange turns.
As you said, an "Open" differential will have the output flanges turn in opposite directions with little to no resistance in rotation.

However, a clutch style LSD's also has spider gears just like the Open diff and when the clutches are warn out the axles can turn in opposite directions also
It is possible your diff has a bad output flange bearing, spider gears/bushings or bad LSD clutches.
When the drive-line does not turn, both output flange bearings, spider gears (LDS clutches) are all that rotate in the diff.
Bad LSD clutches tend to make a grinding sound when they are warn out.

"Elderly Couple"!!
Statement of age bias? What determines elderly? Now we know...

An Old Guy's Perspective:
A 1997, 850 is a 28 year old vehicle. (a classic & old for a car)
So, a couple of 80 years, with means, would have been 52 and not so elderly, when it was purchased new.
Couples that are 'not-in-need-of-employment' may like their Bimmer's with performance upgrades and tuned for long road trips!
Purchased mine 21 yrs ago, just before I was 'not-in-needed-of-employment'.
With that, older guy's can devoted their copious quantities of free time to all their hobbies.
FWIW, I have yet to stop upgrading any of my Bimmer's, to include the 850/M73, 21 yrs later.