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sealions518

Grinding sound in rear on take off

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Hey FAQ - I have searched and searched for a close match to this problem with no luck. Maybe I am not searching the right topic or using the right words. I am including three sounds files for reference.

 

I have a 1972 2002tii that is presenting with an awful grinding sound that seems to be coming from the right rear of the car. The sound happens under load in first gear (sometimes second) when I push the gas pedal a little aggressively. I'm not talking full race mode, but to get it not to do it I have to take off verrry slowly. After that third and fourth gear seem to have no issues but I am also pretty light on the throttle at that time. It's a stock 4 speed transmission btw. It might be worth mentioning that the car sits low on bilstein HDs with stock springs that were cut by a previous owner. The rear sits at 22.5" from ground to wheel well lip - on 13" stock wheels on P185/70R13 tires.

 

HALP!!

 

Cheers, Josh

Tii Grind 1.m4a Tii Grind 2.m4a Tii Grind 3.m4a

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first thing to do is jack it up, all 4 wheels, and climb underneath, and look for shiny spots.

 

On your exhaust. 

 

And on your driveshaft where it sits in the center bearing, and where

it attaches to the trans and sits right below the shifter platform/

And where the differential bolts to things, altho that's a secondary choice.

 

And where the right rear wheel's supposed to be bolted to the hub.

 

and, hell, just for thoroughness, if you haven't found anything yet, rotate the rear wheels and see what you

hear from the hubs and brakes.

 

You can start it and run it through the gears, and look- carefully- at the driveshaft, too.

 

t

 

 

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The two places that come to mind are your right hub/stub shaft and your trans output flange. Start with the right hub is the large, 22mm I believe. nut tight if so jack the tire off the ground and turn the tire forwards and back see if theirs play these cars have been known to wear the splines on the shaft and hub. Next do the left side, if all is tight there then jack the car up and with the tranny in first gear check for free play by rotating the drive shaft. 

 

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That sounds like exhaust hitting the floor.  Probably where it goes over the rear crossmember. In the lower gears when you apply the power it torques the engine to the right which twists the exhaust and the pipe at the crossmember goes UP.  The higher gears do not rock the engine as much.  

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1 hour ago, Preyupy said:

That sounds like exhaust hitting the floor.  Probably where it goes over the rear crossmember. In the lower gears when you apply the power it torques the engine to the right which twists the exhaust and the pipe at the crossmember goes UP.  The higher gears do not rock the engine as much.  


Hmm, interesting, what do you do to stop that?

My car was having a clunk when in reverse backing up a steep hill.  
I’m doing a total front and rear job so think the clunk will stop but wondering what it could be. 

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you rehang the exhaust half a hundred times, and eventually end up with it a lot lower than you think it should be visually.

 

Or run solid engine mounts.

 

t

 

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Thank you for all the replies. I jacked up the rear yesterday and did a very quick look but nothing stood out. I got some better jack stands so hopefully I can take a better longer look soon - I’m working at home with a 2.5 year old so we’ll see how that goes 🙃

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Well I feel like a complete idiot. With all the stuff I've taught myself with this car I can still miss the fact that I am completely missing two bolts holding my diff down (see pic). There was one nut holding with the help of some old grime.

 

Again, I am awful with searching and have no idea what I need - well I know the nut size 😆 I imagine there are a couple of washers? Can anyone help me with the bolt set and where I can find them?

 

Cheers,

 

Josh

IMG_2647.jpg

IMG_2648.jpg

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Realoem.com.  Navigate to classic section and individual parts diagrams for your car.  They list all parts etc with specs.  You will be able to identify the size of the nuts and bolts  you need. 

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6 hours ago, sealions518 said:

Well I feel like a complete idiot. With all the stuff I've taught myself with this car I can still miss the fact that I am completely missing two bolts holding my diff down (see pic). There was one nut holding with the help of some old grime.

 

Again, I am awful with searching and have no idea what I need - well I know the nut size 😆 I imagine there are a couple of washers? Can anyone help me with the bolt set and where I can find them?

 

Cheers,

 

Josh

 

 


I just replaced all the bolts on my subframe and can send you what you need.  PM your info.  The bolts should be installed with the nuts on the bottom btw.  That way you can see if they are loose and not have the whole bolt fall off if the nut comes off.  There are 4 huge washers that goes on the setup that I will send as well.

 

Tom

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What you missing are

Hex bolt    07119914690    M12X1,5X140 (x2) - NLA

Flat washer    33171125439    (x2)

SELF-LOCKING HEX NUT    07129900047    M12X1,5-10-PHR (x2)

I don't know if hex bolts are grade 8.8 or 10.9. You could check other 2 bolts head and determine what grade they should be.

If grade 8.8, need to order this:

https://www.belmetric.com/12x15-fine-c-533_541_389/bft12x15x140blk-hex-bolt-88-black-p-11941.html

 

If grade 10.9 need 2 of this bolts:

https://www.belmetric.com/12x15-fine-c-506_510_406/bh12x15x140pblk-hex-bolt-black-109-partial-p-15746.html

 

and here is the schematic as reference

 

https://www.realoem.com/bmw/enUS/showparts?id=2215-USA-04-1976-114-BMW-2002&diagId=33_0882

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Well I found some free time and was able to get this sorted with the help of Tomphot - thank you Tom for sending me the bolts and such that I needed!! 

 

I love this community!!

 

Cheers,

 

Josh

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