2007 m35x transmission rattle

[midnightclub619]

alright guys...

i was hearing a rattle sound on acceleration. i assumed it was a heat shield rattle. I checked all the heat shields and found that all the shields and clamps are still in really good condition. I didn't see something that should be replaced or removed that was making the rattling. So when i had held the RPM at 1k I would hear the rattle in Park (when on the road it was mostly in 2nd & 3rd gear I would hear this rattle). Since the rattle wasn't coming from the heat shields I found that the rattle was coming from the transmission (I think). This is where I'm not exactly sure but i think this is coming from the transmission. It's directly behind the transmission pan. The pic shows where i'm hearing this rattling come from...



I hope its not the transmission but I hope its something other than that.

Does anyone know what I can do to validate this?

[Ilya]

Does the car vibrate or have issues driving? Or is it just sound? If it was the transmission I would imagine you'd be feeling/seeing other things.

[midnightclub619]

It's just a sound that I hear. No performance degradation.

After further investigation, it sounds like it's coming from the transfer case, not the transmission.

To remedy I went ahead I did a transfer case fluid change and I also changed the differential fluid change. But I'm still hearing this rattle from the transfer case and it's annoying me and also a scary sound. Not sure how to fix this. Maybe I need to replace the entire transfer case but not sure. Has anyone else run into this issue?

I'll post pics tonight of the fluid changes tonight

[midnightclub619]

Here are some instructions on how to change your front & rear differential.

Tools:
Torx 55 (T55) bit
10" extension
ratchet
siphoning pump
drain pan

Differential Oil
SAE 80W-90 API GL-5
Front: 1 3/8 pt
Rear: 3pt

Front Differential
1. The front is fairly easy. The filler and drain bolts are right next to each other.
2. Remove the Filler bolt first and clean that one up (if needed)
3. After you remove the filler bolt, remove the drain bolt and make sure you have a drain pan underneath to catch the oil. Clean up the drain bolt of the metal shavings that the magnet has collected.



4. Replace the drain bolt
5. place the out tube from the siphon pump into the filler hole and pump the suggested amount. If oil starts to leak out that would be a good time to stop pumping
6. Replace the filler bolt


Rear Differential
1. Remove the filler bolt. (The bolt is on the right hand side of the differential)




2. Remove the drain bolt and let it empty and make sure you have a drain pan underneath to catch the oil. Clean up the drain bolt of the metal shavings that the magnet has collected. Once empty, replace the bolt.




3.place the out tube from the siphon pump into the filler hole and pump the suggested amount. If oil starts to leak out that would be a good time to stop pumping
4. Replace the filler bolt


Hope this helps. If I left anything out let me know and I can update.

[midnightclub619]

Looks like I have to keep at it...

So after replacing my Transfer Case I'm still hearing the rattle. I found a heat shield that split that I have since re-tightened down. At this point I have feeling that it could be the transmission but can't confirm. For a minute I thought it could be the catalytic converter but how would i be able to validate
it is the CC? I'm not getting any codes for bad sensors, transmission or CC so at this point I don't know how else to diagnose the rattle.

Would anyone have any idea?

Here's a video of the rattle (ignore the loud heat shield rattle at the beginning of this video, i fixed after recording this)

https://youtu.be/_-FZ-uyI5mg

[steve_c]

Sounds more like a knock then a rattle to me, if I am hearing what you are.
Drop by an auto parts store & pick up a mechanics stethoscope, they are cheap.
Don't get anything fancy, just a hollow metal tube type with the extensions that attach over (or onto) your ears.
If it is a knock, and not a rattle, and you feel it is from the transmission, I would check around the flywheel/torque converter area for loose flywheel bolts. Has the transmission ever been out of the vehicle?
I could easily be over reaching here, and the noise might very well be a rattle. In that case, check to see if the noise is coming from one of your CAT's. People have reported CAT's breaking off from the inside & rattling.

In any event, pinpointing the noise can be greatly aided by a stethoscope, similar the one pictured here:
http://www.tooltopia.com/lisle-52500.aspx

[midnightclub619]

Sounds more like a knock then a rattle to me, if I am hearing what you are.
Drop by an auto parts store & pick up a mechanics stethoscope, they are cheap.
Don't get anything fancy, just a hollow metal tube type with the extensions that attach over (or onto) your ears.
If it is a knock, and not a rattle, and you feel it is from the transmission, I would check around the flywheel/torque converter area for loose flywheel bolts. Has the transmission ever been out of the vehicle?
I could easily be over reaching here, and the noise might very well be a rattle. In that case, check to see if the noise is coming from one of your CAT's. People have reported CAT's breaking off from the inside & rattling.

In any event, pinpointing the noise can be greatly aided by a stethoscope, similar the one pictured here:
http://www.tooltopia.com/lisle-52500.aspx

thanks steve_c... I'll go pick up a stethoscope today. yeah, I agree, knocking is a better word to use

No, the transmission hasn't been removed, I believe... I got the car used with 57k on it so I wouldn't imagine that it would have to be removed with so few miles. I'll be going under the car again today with the stethoscope and hopefully i'll be able to pinpoint where its coming from.
If it is coming from the CAT's, it would be a bit of a relief since repair would be cheaper.

[midnightclub619]

and also what I hear is that the knocking is very noticeable in 2nd gear @ 2500-3000rpms, 3rd gear @ 2500-3000rpms, 4th gear @ 2500-3000rpms (but not as loud as 2nd and 3rd gear)

[midnightclub619]

So I finally took a stethoscope to the car and the results are in... idk why i didn't think of getting one before. Thanks steve_c

I took the stethoscope to the Transfer case, Transmission & left catalytic converter and all sounded smooth and no rattle/knock....however, when I put it up to the right catalytic converter I could hear it clear as day. so with that said, I knew the culprit. I finally got around to taking out the right catalytic converter yesterday and the honeycomb inside actually broke from its frame and was moving back and forth and in turn rattling inside the CAT. the sound resonated down there it was pretty difficult to pinpoint the issue exactly.

This was a huge relief so it wasn't a transmission issue but catalytic converter issue. I was able to find a CARB legal CAT on eBay and awaiting delivery. all should be good and no more stupid rattle/knocking.

[steve_c]

So I finally took a stethoscope to the car and the results are in... idk why i didn't think of getting one before. Thanks steve_c

I took the stethoscope to the Transfer case, Transmission & left catalytic converter and all sounded smooth and no rattle/knock....however, when I put it up to the right catalytic converter I could hear it clear as day. so with that said, I knew the culprit....

You are welcome, glad it worked out!
Those stethoscopes are great, and even if you never need to use it again, no big deal since they are a cheap & simple tool! Pays for itself with just one use!

PS,
Thanks again for the great write up!