Potential Driveline Slack?

[deeldoo]

Guys,

I am experiencing what seems to be a weird situation in my DCT M4.

I normally only drive the car in manual mode and have been using it that way since i bought it, I primarily drive is sport or sport plus with drivelogic 2.

It seems anytime I let off depending on how far i have buried the throttle it feels like something under the car is thudding/moving? Does this sound like slack in the drivetrain? Any idea what it can be?

Before anyone mentions, if i do let off the throttle slowly i do not experience it, and yes that is how to drive a manual but regardless is it normal for the abrupt lift off to cause that constantly?

[MR RIZK]

Movement in the rear diff. If it is slight probably normal if excessive a worn or torn bush.

If you search there are threads about the same discussion.

Search for "thud" rear diff M4 etc

[F36Baker]

Originally Posted by deeldoo

Guys,

I am experiencing what seems to be a weird situation in my DCT M4.

I normally only drive the car in manual mode and have been using it that way since i bought it, I primarily drive is sport or sport plus with drivelogic 2.

It seems anytime I let off depending on how far i have buried the throttle it feels like something under the car is thudding/moving? Does this sound like slack in the drivetrain? Any idea what it can be?

Before anyone mentions, if i do let off the throttle slowly i do not experience it, and yes that is how to drive a manual but regardless is it normal for the abrupt lift off to cause that constantly?

This is the bushing that supports the diff. This is a picture of mine and what it looked like. I was getting the thud sound. You have to get it replaced.

Get under your car and look to see if yours is cracked. It will be on the driver side it's hard to miss.

[Andrew30azs]

I have something similar , after hard driving (I have new bushings on my diff ) my driveway is uphill and sometimes when I reversing I hear loud thud on the back then I’m trying to go I’m forward and reverse again and it’s nothing . What this could be ?

[deeldoo]

Originally Posted by Tobiasz17azs

I have something similar , after hard driving (I have new bushings on my diff ) my driveway is uphill and sometimes when I reversing I hear loud thud on the back then I’m trying to go I’m forward and reverse again and it’s nothing . What this could be ?

Would not worry about it, any incline or decline you have to bury the brakes in and even then you do get a thud from the transmission shifting.

What i have learned is these M cars make a lot of noise.