Transmission Clunking Noise

[Rataborn]

Hey Guys,

I have been trying to find I fix for my clunking I hear when driving. I have replaced the rear diff, driveshaft CV joint, engine and transmission mounts, and transmission clutches which were done at the dealership. I am out of options on what else to do. I always hear the noise when I take my foot off the gas pedal at any speed. The dealership said it is normal. It's the engaging and disengaging of the clutches. Its weird that it sounds like it is coming from the rear of the car. I found this video on YouTube which sounds similar to what mines is doing. Let me know what you think.

Thanks

[M5Rick]

What about the diff mount torque bracket, was that checked.

[Rataborn]

Originally Posted by M5theonlyone

What about the diff mount torque bracket, was that checked.

If it's that bracket on the front of the diff, it was replaced.

[M5Rick]

It's the one at the back that needs to be checked.

[Rataborn]

Originally Posted by M5theonlyone

It's the one at the back that needs to be checked.

That was checked and didn't need to be replaced.

[Dwaynos]

Was the entire shaft replaced? You could have movement in the Universal joints which are part of the shaft and cannot be replaced. There could be movement in the rubber donut at the front of the shaft. Also check that the output shaft nut on the gearbox is tight, unlikely it came loose but worth checking. What about movement in the rear driveshafts/axles?

[M5Rick]

Originally Posted by Dwaynos

Was the entire shaft replaced? You could have movement in the Universal joints which are part of the shaft and cannot be replaced. There could be movement in the rubber donut at the front of the shaft. Also check that the output shaft nut on the gearbox is tight, unlikely it came loose but worth checking. What about movement in the rear driveshafts/axles?

So UJ's can't be replaced on prop shaft..you have to replace the whole shaft.

[Dwaynos]

Originally Posted by M5theonlyone

So UJ's can't be replaced on prop shaft..you have to replace the whole shaft.

Most propshafts are like this now. Off roading 4x4 shafts usually have serviceable UJs though.

I did have a rear wheel drive Chrysler come in to work with a similar clunking noise and was a loose rear driveshaft. With the nut not being tight it allowed the slightest movement on the spines. The M5 shafts are not splined in the conventional way however but definitely worth checking.

[Rataborn]

Originally Posted by Dwaynos

Was the entire shaft replaced? You could have movement in the Universal joints which are part of the shaft and cannot be replaced. There could be movement in the rubber donut at the front of the shaft. Also check that the output shaft nut on the gearbox is tight, unlikely it came loose but worth checking. What about movement in the rear driveshafts/axles?

No, the whole driveshaft was not replaced. They said the center bearing was fine and UJ was good to. I just took a spot in the dark on the driveshaft CV. Where is this output shaft nut at?

[Dwaynos]

Originally Posted by Rataborn

No, the whole driveshaft was not replaced. They said the center bearing was fine and UJ was good to. I just took a spot in the dark on the driveshaft CV. Where is this output shaft nut at?

You would have to disconnect the shaft from the transmission. There will be large nut holding the flange to the transmission output shaft. It's unlikely its loose but worth checking. As are the axle bolts that go through the wheel hubs.

[technician117]

The noise in the video sounds similar to a noise I had for a while. It's a metal on metal contact noise? If so, it's probably not any of your bushings or mounts. My problem turned out to be 1-2 poorly torqued bolts in one or two different spots: The 6 bolts that secure the exhaust plate to the body AND/OR it was the bolts that secure the rear reinforcing bracket under the diff/subframe. I tightened and retorqued these and the noise went away. My noise came from the back. It was repeatable. I thought it was an axle or maybe even driveshaft as the noise happened when transitioning engine load, same as that video.

Good luck and keep us posted!

[Rataborn]

Originally Posted by Dwaynos

You would have to disconnect the shaft from the transmission. There will be large nut holding the flange to the transmission output shaft. It's unlikely its loose but worth checking. As are the axle bolts that go through the wheel hubs.

Thank you. I will get the car up and check that.

[Rataborn]

Originally Posted by technician117

The noise in the video sounds similar to a noise I had for a while. It's a metal on metal contact noise? If so, it's probably not any of your bushings or mounts. My problem turned out to be 1-2 poorly torqued bolts in one or two different spots: The 6 bolts that secure the exhaust plate to the body AND/OR it was the bolts that secure the rear reinforcing bracket under the diff/subframe. I tightened and retorqued these and the noise went away. My noise came from the back. It was repeatable. I thought it was an axle or maybe even driveshaft as the noise happened when transitioning engine load, same as that video.

Good luck and keep us posted!

Thank you. I will have to find this reinforcing bracket in the rear and retighten everything. It's just weird that it is so hard to find this annoying issue. It's definitely horrible in stop and go traffic.

[technician117]

Originally Posted by Rataborn

Thank you. I will have to find this reinforcing bracket in the rear and retighten everything. It's just weird that it is so hard to find this annoying issue. It's definitely horrible in stop and go traffic.

The exhaust plate is mid car, a little closer to rear and supports the exhaust. The reinforcing bracket is easy to find... it's the big stamped aluminum "skid plate" under the diff.

[94jedi]

Not normal for sure....keep us updated; let us know what the fix is.

[BeachM5nster]

Originally Posted by Rataborn

Hey Guys,

I have been trying to find I fix for my clunking I hear when driving. I have replaced the rear diff, driveshaft CV joint, engine and transmission mounts, and transmission clutches which were done at the dealership. I am out of options on what else to do. I always hear the noise when I take my foot off the gas pedal at any speed. The dealership said it is normal. It's the engaging and disengaging of the clutches. Its weird that it sounds like it is coming from the rear of the car. I found this video on YouTube which sounds similar to what mines is doing. Let me know what you think.

Thanks

i may not know much, but if you have an issue and you repeatedly molest it like the lady in the video, youll break it completely before you can fix it

[E93M3ofSFL]

Originally Posted by BeachM5nster

i may not know much, but if you have an issue and you repeatedly molest it like the lady in the video, youll break it completely before you can fix it

Any updates on this ...

Just had a custom made exhaust done and I am getting this clunking noise as well ...

[SapphireM5]

Originally Posted by E93M3ofSFL

Any updates on this ...

Just had a custom made exhaust done and I am getting this clunking noise as well ...

check to see where your exhaust is touching the frame.

[E93M3ofSFL]

Originally Posted by SapphireM5

check to see where your exhaust is touching the frame.

Will do ... thanks

[SapphireM5]

Originally Posted by E93M3ofSFL

Will do ... thanks

There is a cross brace right by the trans, it looks like a thin pipe. I bet thats touching the trans.

[E93M3ofSFL]

Originally Posted by SapphireM5

There is a cross brace right by the trans, it looks like a thin pipe. I bet thats touching the trans.

Thanks for the input, will make sure to post outcome

[CryptoHeff]

Originally Posted by E93M3ofSFL

Thanks for the input, will make sure to post outcome

Reviving an old post. Can't see the original YouTube video anymore - but was this resolved?