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View Full Version : UH OH!!!! rear end?


E36pilot
01-16-2004, 05:37 PM
Ok a little background here. I have purchased my first E36 M3 back in August. It had 60,000 miles on it with a warrannnty good until 80,000. This issue started about 6 weeks ago and is loder than ever now. When I pull off of a stop I get a one time thump noise, also when I shift gears as well. I noticed it also occurs when I take corners too. At first I thought maybe it was the sound of bad stuts, but now it seems to interact more with my releasing of the clutch. Loose rear end? Driveshaft? am I totally off? Anyone have anything remotely close to this sound? thanks in advance!

chromius
01-16-2004, 06:06 PM
I don't know if this apllies to e36's also, but I have the same problem with my e30, and it also makes the thump when braking and pushing the clutch in.

There was a thread a while back about some others having this problem, and what it came down to was the flex coupling on the drive shaft that needed replacing. I am planning on replacing mine soon, and hopefully it fixes the problem. I suppose it could also be the transmission mounts, and/or the subframe bushings, however, I replaced both of these on mine and it did not fix the problem. Hope this helps.

E36pilot
01-16-2004, 06:41 PM
HUH, well I am sorry to say, but I'm glad that someone else can relate. I will look at the clamp and see whats up.

chromius
01-16-2004, 07:10 PM
yeah apparently its a pretty cheap part, like $40 or something like that....and its just a disc that bolts in made of a hard rubber I believe. I checked the service manual on it, and there is no specified change interval, but it does say that it can wear out over time, with road grit and the tourque of the engine, so its a good possibility that it's the problem.

Jattdee328
01-16-2004, 07:42 PM
motor or tranny mount is my best bet.
take it in and find out.

crazyvadim
01-16-2004, 08:42 PM
Originally posted by Jattdee328
motor or tranny mount is my best bet.
take it in and find out.

I second that.

E36pilot
01-16-2004, 09:37 PM
It may be a tranny mount, however the noise clearly comes from the back of the car.......the trunk if you will. This is why I initially thought it might be bad struts. So maybe this piece lies at the end of the drive shaft, the rear universal joint or perhaps the differential input flange. I picked up a 3 series service manual from Barnes & Noble, here is what it had to say:

Symptom = Noise on/off throttle or when engaging clutch.

Probable cause = Final drive components worn, or driveshaft mounting flanges out of round or damaged.

Probable cause # 2 = Drive axle or CV joint faulty.

Probable cause # 3 = Sliding coupling siezed.

E36pilot
01-16-2004, 09:45 PM
Man to top it off I have to replace my thermostat this weekend as well. I was hoping this ride wasn't going to require alot of maintenance......BMW doesn't = Porsche :D

crazyvadim
01-16-2004, 09:48 PM
Originally posted by E36pilot
Man to top it off I have to replace my thermostat this weekend as well. I was hoping this ride wasn't going to require alot of maintenance......BMW doesn't = Porsche :D

Thermostat is an easy job to do,basic tools needed.If you wanna save money start doing these small jobs by yourself.

E36pilot
01-16-2004, 11:36 PM
Yeah I am, in fact these are the first and hopefully last for awhile repairs that I will do on a German car. I have worked alot on American and Jap cars......never a Bimmer tho. I dunno if the warrannty will cover it, I will do all simple repairs myself anyway.

Autotechnica
01-17-2004, 03:09 AM
Check your sub-frame (differential carrier mounts), you could have a cracked rear sub-frame.

When your carrier mounts are cracked the thud noise you actually hear is the differential hitting against your chassis. It's most noticeable when you're changing gears. This is usually a result of improper shifting techniques or just plain abuse.

Hoist your car up and get a mechanic to check it out immediately. Driving around with a cracked rear sub-frame is very dangerous. Avoid highway driving until you comfirmed the problem is not the rear sub-frame.

Just a note 1991-1993 E36 models had weaker rear sub-frames and it was actually a common problem that they cracked. Usually a $600-$800 job depending on the shop. M3's have stronger reinforced sub-frames. However, because of the power cracked M3 rear sub-frames are also quite a common problem.

This is the sub-frame, the only thing holding your differential and your wheels to the rest of the chassis. This is NOT the sub-frame bushings.

Bryan

E36pilot
01-17-2004, 03:33 AM
What the hell? This sounds like BS to me, I mean if it's a common problem then perhaps they should address it. I didn't pay 22K for a piece of s**t. Geez my import was rated for 140 HP, I boosted it for an additional 80HP and NEVER any issues with drivetrain etc. This weekend I'll take a look, can you tell me this, if it is in fact a rear sub frame then would this persist or should I say evolve over time or all at once? My issue seemed quiet and became louder as time goes on. Thanks a million you guys for all this help, man my stomach is turning now. I'll be honest, if this piece costs me 1K to fix on top of my thermostat and other piss ant issues....this bitch is goin up 4 sale!!!!!!! My German experience will be over, I didn't get this car to become a mechanic, fix odds n inns sure, but not welding sub frames etc....what the hell. I do hope this is not my issue.

Autotechnica
01-17-2004, 03:45 AM
Originally posted by E36pilot
What the hell? This sounds like BS to me, I mean if it's a common problem then perhaps they should address it. I didn't pay 22K for a piece of s**t. Geez my import was rated for 140 HP, I boosted it for an additional 80HP and NEVER any issues with drivetrain etc. This weekend I'll take a look, can you tell me this, if it is in fact a rear sub frame then would this persist or should I say evolve over time or all at once? My issue seemed quiet and became louder as time goes on. Thanks a million you guys for all this help, man my stomach is turning now. I'll be honest, if this piece costs me 1K to fix on top of my thermostat and other piss ant issues....this bitch is goin up 4 sale!!!!!!! My German experience will be over, I didn't get this car to become a mechanic, fix odds n inns sure, but not welding sub frames etc....what the hell. I do hope this is not my issue.

BMW was aware of the problem. Many '92 E36's have had this problem come up. At 12+ years how can BMW still be responsible for any wear or damages on the car? 2 years ago my 1992 318i had a rear sub-frame failure, it costs $650 for me to have it repaired. This happened to 2 other people I know with 325's, and even 1 person I knew with a '96 328! In the states I've read on many message boards that even the M3 has rear sub-frame failures due to hard driving or improper shifting. BMW simply cannot recall this problem, it would put them out of business.

Anyways, this problem builds up over time. At first it's just a small thud sometimes when you shift, later it gets more obvious as you start to hear it on almost every shift, when you depress the clutch and release as well. When it's really bad it's loud and you can feel the "thud" on your body like something is hitting against the bottom of your car. When the sub-frame cracks there is nothing else holding your differential to the rest of the chassis except for 3 bolts. If this isn't the problem, great! If it is, I'm warning people to make them worry, this is a serious problem and if ignored could cause a serious accident resulting in death.

This problem is usually caused by improper launching techniques. Avoid dumping the clutch and high revving when launching your car, try to slip the clutch. Anything that puts a lot of pressure on the sub-frame will cause cracks or damage. Very common in E36's which are tracked. Although it's rare to see sub-frame failures on newer E36's, it's not unheard of. If you drive your car hard you should suspect this as a possible outcome.

Good luck, and please post your findings,

Bryan

E36pilot
01-17-2004, 04:32 AM
Well I'll tell ya, I drive the hell out of this thing so I'm betting your right. I went through a set of SO3's in roughly 9K miles. I may not be the best shifter..... I honestly don't think I shift improper, but maybe I do. I can get er to run 14.1 now at the track whic is what it's suppose to do on paper. If I was shifting improper I'm guessing I wouldn't be ablee to pull off these times. I do drive hard cause every day I get into it I serously smile and and think to myself how lucky I am to own this thing and what a pity it would be not to mash the gas pedal. I love EVERY aspect of it from the luxerous feel to the screaming engine and man.......I have to say this is a blow. Tomorrow I am going to check it out, I have my service manual open and am getting geared up as we speak. I already have a welding shop lined up (FREE thank goodness) should be asy to produce a clean weld on such a new frame, with no rust etc.... Thanks for all the advice as well as help, ya know a proper weld can actually be as strong/ somtimes stronger than the material itself so maybe I'll keep it awhile after all....cause I *love* this ride!! I was considering selling my 98 boosted Integra and grabbing a supercharger, however that doesn't appear to be a bright idea, I mean adding an additional 150HP and all on a subframe known to give way to 240HP. BTW what do the Germans do with the 321HP model, they really must catch hell over there.

E36pilot
01-17-2004, 04:41 AM
The more I think about it the more I realize that my launches go rather smooth. If anything the Potenza SO3's bite to well if that even makes sense. there are times when the tires bite and the car just can't propell itself out of the hole. It's like ALL the tension/ pressure is placed back to the rear end and it takes a sec for the car to build inertia and release the pressure with the higher RPM's. It felt as if the car would bind for a sec, the tires wouldn't spin. Does this make any sense? I mean lets be real 240HP isn't s**t. I mean Saturn has a cracker Jack Box SUV now with this HP rating, hope that crappy subframe doesn't give way.

Autotechnica
01-17-2004, 04:55 PM
Just another note. When/if you reweld the rear sub-frame, there are custom racing plates you could (should) have welded ontop for extra reinforcement. It's actually an improvement and much stiffer. I had these welded into my '92 318 and the rear end was very very stiff, you have to watch out in the rain though, it's very easy to spin out. On dry road the hanlding is amazing.

I can give the number of a place that makes these plates or you can purchase them from Turner Motor Sports. They are relatively cheap, only $40 each I believe.

Having someone who can weld it for you is a plus. If you have a hoist you should be able to remove everything yourself within a day.

Good luck,

Bryan

E36pilot
01-17-2004, 05:48 PM
Yeah dude, I'll take the number. Not 100% certain this is what the problem is, but it sure sounds like it. Do you have a link displaying these plates? I have access to 100 ton hoists as well as certified welders FREE of charge. In fact I have access to ANY amount of steel I need. 80 bux is cheap, but if it's simply just a plate with the hole locations already called out I can make them myself. # and or link would be appreciated! *th-up*

E36pilot
01-19-2004, 02:52 AM
Well I decided to drive it up to the BMW dealer to have it checked out and guess what? On the way up there I heard a loud noise and then it passed, a short time later it was done. Whatever I did is now complete, whenever I accelerate the U joint rises and ends up rubbing against the body of the car. I was about 7 miles from my destination so I feathered it there, starting off in second and thifting to third, it appears under load this knuckle rises and hits the body, also when I placed the E36 into reverse..NO NOISE. Now since the drive shaft is spinning the opposite direction it would then fire down under load right? Anyhow I think itwas the subframe, hope this is considered drivetrain. A neat side to the story, my guy has an 02 330 that I trucked home in and on top of that he is storing a friends 03 M3 in the garage. This M3 even had the SMG tranny, interesting setup...first one I've ever seen up close. CYA!

R_JAY
01-19-2004, 04:54 AM
Damn that sucks. Atleast you're not letting it get you down much. Keep us informed about the actual findings and cost of repair.

thinair
01-19-2004, 09:26 AM
Check your rear shock mounts if they're worn/torn, your rear toe arm bushings for a lot of side to side play, and/or see if the subframe bushings are tight or worn.

The 98 M3 already had reinforcement plate welded in to the chassis at the subframe mounts from factory did it not?

chromius
01-19-2004, 12:23 PM
If it were the rear subframe that was cracked would he not hear the same "thump" while going over bumps?

E36pilot
01-19-2004, 01:51 PM
it's not necessarily from going over bumps, just normal driving. I mean anytime I apply pressure to the driveshaft (gas) then it's as if the shaft rises up and actually rubs on the body of the car. I had to go from first to third and go real gradual on the gas just to get it to the dealership.....we shall see. I' m driving my boosted Integra right now, so this is why I am not constantly complaining....it's not so bad::

Wilwood big brake kit (front)
Brembos/ ECB Greenstuff (rear)
B16A boosted
18x7.5 Konig Theory wheels
Nuespeed springs
Tokiko struts
full leather
momo Jet wheel
the list gos on....................I've gone "ricey" for the winter

E36pilot
01-21-2004, 01:07 AM
OK the verdict is in!!!!!!! this cat over at International Autos in Milwaukee says I broke off the bolts that hold the diff......clean! I suppose that is MUCH better than the subframe. They are going to drill out the material left in the frame and re insert the new bolts for a mere $200.00. Hes says $95.00 an hour at 1.5 hours plus parts. Well there we have it, it was the CV touching the body. I aksed the guy "am I just driving it to hard", he responded with, "isn't that why you bought an M3". I was like yeah, to drive not to bring in to you guys....LOL CYA!

Autotechnica
01-21-2004, 01:33 AM
Originally posted by E36pilot
OK the verdict is in!!!!!!! this cat over at International Autos in Milwaukee says I broke off the bolts that hold the diff......clean! I suppose that is MUCH better than the subframe. They are going to drill out the material left in the frame and re insert the new bolts for a mere $200.00. Hes says $95.00 an hour at 1.5 hours plus parts. Well there we have it, it was the CV touching the body. I aksed the guy "am I just driving it to hard", he responded with, "isn't that why you bought an M3". I was like yeah, to drive not to bring in to you guys....LOL CYA!

Actually that does mean your "sub-frame" is cracked. The carrier mounts are attached to your sub-frame which hold your differential. When the carrier mounts break apart from your sub-frame the only thing holding it are 3 bolts (as I mentioned in my previous posts). If your bolts broke off as well, that means you have sub-frame damage. Your lucky you didn't spin out, if the bolt breaks off that's already the later stages of a cracked sub-frame.

Bryan

E36pilot
01-21-2004, 03:05 AM
So whats the deal then with regards to repair? Sounds like they are just replacing the bolts when in reality they need to fix the subframe and the bolts as well? My Bently book just doesn't touch on the mounting to the sub frame so I'm having a tuff time visioning what exactly is going on. I am new to rear wheel drive as I understand other models work this way as well (Infinity/Lexus etc). Thanks for the feedback!

E36pilot
01-24-2004, 03:15 AM
And to top it off!!!!!!!!!! The mechanic had the guy on the phone mention to me that this was NOT the first time this has happened on my ride. Cmon, how the hell are you suppose to know this happened? :confused: I feel like *uzi* the guy for not telling me, but it had two owners so who knows which it was.....besides they are not obligated to tell me anyhow, but would have been nice to know. CYA!