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-   -   E46 325xi - Driveline shudder in reverse - similar to locked diffs (http://forum.e46fanatics.com/showthread.php?t=820559)

TomThomas 02-01-2011 09:33 PM

E46 325xi - Driveline shudder in reverse - similar to locked diffs
 
Hello all,

This is my first post to the forum. I recently had a 2003 325xi fall into my lap - it was a deal too good to pass up; and I've been meaning to try out the other AWD systems from various manufacturers. Our last 7 cars have been Audi's - I consider myself an expert in owning and maintaining them. The only thing my vehicles go to the shop for is tires and alignment (20 years shop-free!)

I've searched the forums, and the web in general, but I am unable to find a solid answer to my question:

When I back this vehicle up with the steering turned at a modernate to full angle, the car shudders. This "shudder" is *exactly* the same as when the rear diff, or the center diff (in a non-torsen vehicle) is locked and the vehicle is turning. It feels as thought the tires aren't able to turn at the large difference in rate between them.

My understanding of the E46's AWD system is that all three (center, front, and rear) differentials are open (I know the center is a transfer case, rather than a real differential). But, something must be happening in the center diff to force the 68/32 torque split. I suspect this is the issue - if this is normal behavior.

Is this driveline shudder (one tire "scrubbing" since it can't turn at the rate it would like) normal? The car seems to drive fine, even at the limits - the only symptom is when reversing and turning.

Thanks for the help in advance.

Tom

SamDoe1 02-02-2011 12:46 AM

Front axles and CV joints. Replace them.

feddomw 02-02-2011 04:47 AM

I recently started a thread on this too. Some good comments there, yet no definitive answer. Thread on this Xi board. EDIT: here it is http://forum.e46fanatics.com/showthread.php?t=810841

The problem is the same as yours, I would describe it more as a "binding" feeling. I did not have it this bad on my Quattros or a Golf I had from 2001 which was a 4Motion and had the Haldex unit.

I don't like SamDoe's "solution" as it feels like a cop-out. I prefer a diagnosis before I fix things or have them fixed. My CV joints are fine BTW.


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TomThomas 02-02-2011 10:16 AM

CVs and Axles?
 
I drive the hell out of my cars - buy them at 100K, and sell them at 400K plus - I've never had CV issues act like this. I'm still thinking it has something to do with the transfer case not being a true open diff. Are there xi owners out there that can verify thier car DON'T skip or shudder in reverse and full lock?

Tom

scottz 02-02-2011 10:58 AM

Quote:

Originally Posted by TomThomas (Post 12761885)
I drive the hell out of my cars - buy them at 100K, and sell them at 400K plus - I've never had CV issues act like this. I'm still thinking it has something to do with the transfer case not being a true open diff. Are there xi owners out there that can verify thier car DON'T skip or shudder in reverse and full lock?

I will check mine at lunch

SamDoe1 02-02-2011 11:07 AM

Quote:

Originally Posted by TomThomas (Post 12761885)
I drive the hell out of my cars - buy them at 100K, and sell them at 400K plus - I've never had CV issues act like this. I'm still thinking it has something to do with the transfer case not being a true open diff. Are there xi owners out there that can verify thier car DON'T skip or shudder in reverse and full lock?

Tom

Mine does not. I use full lock in reverse every day to get out of my garage at home. The transfer case should not be an issue. The CV joint failure is a known and documented issue. If you check them and find them to be in good condition then we can talk about other reasons but as of right now, that's where I am pointing the finger. The CV joints are what allow your wheels to turn at any given angle. If they are bad, they will bind. The TC rarely if ever goes bad. If it's not your CV joints then I would look to the front diff before you point at the TC.

Just to add a little more info regarding the TC:
Quote:

Originally Posted by Mark M (Post 12761807)
Ok....here are the simple observations from the test of the NV124 case on my workbench.

- Spinning input shaft by hand.....both output shafts rotate
- Spinning input shaft by hand and holding rear output shaft stationary.....front output shaft rotates.
- Spinning input shaft by hand and holding front output shaft stationary.....rear output shaft rotates.

Caveat....these tests were done with spinning by hand, which does not simulate rear world forces transmitted into the driveline.

Thus, my conclusion, you can NEVER make an XI into a rear wheel drive by simply disconnecting front driveshaft. It will just send all the power to the front output shaft and spin endlessly without putting power to the rear.

This shows you that the TC is not a "locked" center differential, it is actually open. If you have CV joints that last 100k you are either the luckiet person in the world or someone didn't tell you they replaced them.

Quattro and/or 4motion are different AWD systems and is comparing apples to oranges.

SamDoe1 02-02-2011 11:11 AM

Quote:

Originally Posted by feddomw (Post 12761517)
I don't like SamDoe's "solution" as it feels like a cop-out. I prefer a diagnosis before I fix things or have them fixed. My CV joints are fine BTW.

It's not a cop out at all. It's a known and documented issue. How did you go about determining your CV joints are good?

Also, I replied with an answer to your other thread regarding your clunking issue.

feddomw 02-02-2011 11:27 AM

Quote:

Originally Posted by SamDoe1 (Post 12762016)
If it's not your CV joints then I would look to the front diff before you point at the TC.


Quattro and/or 4motion are different AWD systems and is comparing apples to oranges.

We're running this issue in two threads here. Can we merge them???

BAck OT: Agreed that Quattro is different, just saying that I had some binding with those as well, and I think the Xi is somewhat more "rough/primitive" in terms of tech. Gut feeling, I can't substantiate this claim in any way.

My CV boot was torn, they checked it, it was fine, they put a new boot on and packed it with grease. "They" could be wrong, but that kind of thinking where I second guess everyone has gotten me into trouble before.

feddomw 02-02-2011 11:32 AM

Quote:

Originally Posted by SamDoe1 (Post 12762031)
It's not a cop out at all. It's a known and documented issue. How did you go about determining your CV joints are good?

Also, I replied with an answer to your other thread regarding your clunking issue.

See my post above. No offense meant, it's just that I want a diagnosis before I have things fixed.

Gearbox clunking in other thread: :dunno:
Had an e36 325 with 230K km before, original gearbox, silky smooth gear changes. Also had en e46 manual before, same thing, smooth. Gearbox also "sticks" in front of 5th gear when in neutral, also documented issue, also annoying. Makes finding 3rd gear interesting for sure...

SamDoe1 02-02-2011 12:14 PM

Quote:

Originally Posted by feddomw (Post 12762062)
We're running this issue in two threads here. Can we merge them???

BAck OT: Agreed that Quattro is different, just saying that I had some binding with those as well, and I think the Xi is somewhat more "rough/primitive" in terms of tech. Gut feeling, I can't substantiate this claim in any way.

My CV boot was torn, they checked it, it was fine, they put a new boot on and packed it with grease. "They" could be wrong, but that kind of thinking where I second guess everyone has gotten me into trouble before.

You can easily check for yourself, just turn the wheel all the way and drive slowly. If you hear clicking, the axle is dead. It's that easy.

feddomw 02-02-2011 12:50 PM

I'll try this tomorrow. Describe "clicking". Do you mean clicking as in that I can feel the play in the front wheel assembly on both sides? The clicking would be the play due to the increased tolerances.


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SamDoe1 02-02-2011 01:33 PM

Quote:

Originally Posted by feddomw (Post 12762372)
I'll try this tomorrow. Describe "clicking". Do you mean clicking as in that I can feel the play in the front wheel assembly on both sides? The clicking would be the play due to the increased tolerances.


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Clicking as in sound. Roll your window down...

TomThomas 02-03-2011 02:58 AM

xi binding in reverse
 
So, it sounds like the CV's are an issue in these vehicles. I questioned this at first - I've never had a CV go out/bad on any of my previous cars (Audis - 7x) unless the boot was torn and dirt had gotten in there. I'm talking 400K (very hard, but very well maintained) miles in almost every vehicle without a CV ever going bad.

My CV's pass the classic test - full lock turn without clicking - are people saying they can still be bad and still pass this test? I am also assuming that we are talking about the front outside CVs? - they are the only ones that really get stressed in normal operation. Can I lift the car up and check for looseness in the CVs (twisting them), or binding in neutral?

If it is bad CV's causing this issue, I'm assuming the tracks in the CV joint are worn in a way that stressed forward they operated normally, but in reverse the wear and tear is evident (more loose?)

I appreciate all the input, and as a BMW newbie (but well-versed in Audi / Audi quattro), I know to rely on the forums. It's just at this point, I haven't lurked long enough to know who really knows what the issue is, and who is full of sh*t. No offense intended (seriously).

So, should I rebuild the outside front CVs, or are all CV joints in these model cars a weak spot? Should I rebuild the entire half-shafts? I really appreciate the help.

colo330xi 02-03-2011 03:17 AM

Stupid question, but are the rims stock? There's always talk of offset/staggered rim setups causing issues on Xi models.

I think the previous posters talking about CV failure are talking about torn boot, grease spilled out type failures. Axles with grease in them tend to stay happy.

The only other idea i can throw out is that the transfer case, diffs and transmission are all listed by BMW as a lifetime fill fluid. I changed all of these finding the fluid in varying condition. The transfer case was by far the worst.

My thought is really broken down fluid in the t-case could cause some drag, and the hopping/scrubbing. I may be completely wrong here, but the t-case fluid NEEDS to be changed at some point.

feddomw 02-03-2011 04:05 AM

In my case: stock rims, not staggered.

FYI: staggered is allowed and was offered OEM as an option. If kept within spec, it should theoretically not pose a problem.


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feddomw 02-03-2011 08:29 AM

Just checked. No clicking, just like Tom.

I will explain as best I can, and I think I discovered something

I am more and more convinced that this problem (in my case) is connected to the "shudder" I feel sometimes as described before.

I can reproduce it easily: right at the point the clutch engages, I can feel the driveline has a shudder. Obviously I can only feel this from a standstill start. Going very slowly, just letting the clutch engage without using the acceleration pedal, steering wheel straight, shudder until rolling and clutch fully engaged.

It's obviously something which has "play" that is causing the shudder and is only felt under load, i.e. a standstill start as the car has to overcome inertia.

I think this is the same when driving backwards and is aggravated with the steering wheel turned, as the inertia which has to be overcome is much greater with the wheels turned. I don't think I noticed it before because generally you dive straight forward, and turning backwards if you get what I mean. I never if ever drive forward with the steering wheel turned.

The shudder is less pronounced when driving backwards straight, but maybe because the reverse gear is a much lighter gear than first gear, thus easier to overcome inertia?

Transmission guys have not called me back yet, which is disappointing. I will have to call them and drive by again, but it's not exactly around the corner....

SamDoe1 02-03-2011 10:12 AM

Quote:

Originally Posted by colo330xi (Post 12765842)
Stupid question, but are the rims stock? There's always talk of offset/staggered rim setups causing issues on Xi models.

I think the previous posters talking about CV failure are talking about torn boot, grease spilled out type failures. Axles with grease in them tend to stay happy.

The only other idea i can throw out is that the transfer case, diffs and transmission are all listed by BMW as a lifetime fill fluid. I changed all of these finding the fluid in varying condition. The transfer case was by far the worst.

My thought is really broken down fluid in the t-case could cause some drag, and the hopping/scrubbing. I may be completely wrong here, but the t-case fluid NEEDS to be changed at some point.

It does but the transfer case is a geared case. If you have hopping between gears or gear teeth, you have far more issues than a fluid change will fix...

Quote:

Originally Posted by feddomw (Post 12766132)
Just checked. No clicking, just like Tom.

I will explain as best I can, and I think I discovered something

I am more and more convinced that this problem (in my case) is connected to the "shudder" I feel sometimes as described before.

I can reproduce it easily: right at the point the clutch engages, I can feel the driveline has a shudder. Obviously I can only feel this from a standstill start. Going very slowly, just letting the clutch engage without using the acceleration pedal, steering wheel straight, shudder until rolling and clutch fully engaged.

It's obviously something which has "play" that is causing the shudder and is only felt under load, i.e. a standstill start as the car has to overcome inertia.

I think this is the same when driving backwards and is aggravated with the steering wheel turned, as the inertia which has to be overcome is much greater with the wheels turned. I don't think I noticed it before because generally you dive straight forward, and turning backwards if you get what I mean. I never if ever drive forward with the steering wheel turned.

The shudder is less pronounced when driving backwards straight, but maybe because the reverse gear is a much lighter gear than first gear, thus easier to overcome inertia?

Transmission guys have not called me back yet, which is disappointing. I will have to call them and drive by again, but it's not exactly around the corner....

All manual transmission cars will "shudder" to some extent when you do that. If yours has excessive shudder, I doubt it will be an axle issue but it might be a clutch issue. If it's an axle issue, you will be able to feel the shudder in the steering wheel. If you feel it throughout the car, then it's likely something else. If it was an axle or other drivetrain issue, you'd notice it at all lower speeds right? How many miles?

SamDoe1 02-03-2011 10:17 AM

Quote:

Originally Posted by TomThomas (Post 12765805)
So, it sounds like the CV's are an issue in these vehicles. I questioned this at first - I've never had a CV go out/bad on any of my previous cars (Audis - 7x) unless the boot was torn and dirt had gotten in there. I'm talking 400K (very hard, but very well maintained) miles in almost every vehicle without a CV ever going bad.

My CV's pass the classic test - full lock turn without clicking - are people saying they can still be bad and still pass this test? I am also assuming that we are talking about the front outside CVs? - they are the only ones that really get stressed in normal operation. Can I lift the car up and check for looseness in the CVs (twisting them), or binding in neutral?

If it is bad CV's causing this issue, I'm assuming the tracks in the CV joint are worn in a way that stressed forward they operated normally, but in reverse the wear and tear is evident (more loose?)

I appreciate all the input, and as a BMW newbie (but well-versed in Audi / Audi quattro), I know to rely on the forums. It's just at this point, I haven't lurked long enough to know who really knows what the issue is, and who is full of sh*t. No offense intended (seriously).

So, should I rebuild the outside front CVs, or are all CV joints in these model cars a weak spot? Should I rebuild the entire half-shafts? I really appreciate the help.

Torn boots are not the only issue that can cause CV failure. You can also have failure if the boot clamp comes loose and lets all the grease out of the boot, also common. What you can do is to try and clean and repack the joint with new grease and see if that helps. I don't think the CV joints can be rebuilt easily on these cars, you're better off swapping the whole axle assembly out.

Both inner and outer CV joints are a weak spot on these cars. Front only though. And yes, rebuild/replace the whole half shaft.

This might be a long shot, but have you checked your brakes for any binding there? It might be a shot in the dark but worth a quick look.

pilotlviv 02-03-2011 01:37 PM

4 Attachment(s)
I have had the same problem (ACPP), the photo shows the outside all dry (grease was in excellent condition), but visible wear affects the vibration. Verdict - replacing CV joints (mileage 100***1082;)

TomThomas 07-04-2011 02:46 PM

A final update to this thread ***possible solution***
 
I've noticed that since I went through and changed the driveline fluids (trans, front, center, and rear diff) that this problem has gone away. The only other thing I did that was possibly related (but I doubt it) was that I changed tires. Now, I suspect that changing the center diff (well, transfer case) fluid fixed this problem.

I used Redline 75W90 at the ends, Redline MTL in the transfer case, and BMW OEM (Castrol Dextron 6 - $11 at the dealer, $3 or $4 elsewhere) for the transmission (I have the French GM slushbox). I hope this helps someone else, please report if it does!

(Biggest peeve about the car - the Tiptronics in the Audi's shift opposite to the BMW's; it can be embarrassing!)

Tom
2003 325xi


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