#### Luke

##### Well-known member

I know a few folks here, notably CP and myself, have been looking for ways to fix the deceleration noise that plaques many DSMs and GVR4s alike.

Last weekend, I adjusted my driveshaft angle with a magnetic angle-finder. Note that our driveshafts has 3 U-joints. When two sections of driveshaft are connected by a U-joint, the sections would actually accelerate and decelerate as they complete a single revolution. Therefore it is important to either minimize the angle, or have two neighboring U-joints setup in such a way so that this accel/decel cancels each other out.

More info on this is here.

Also note that the lobro joint on our driveshaft is a constant-velocity joint, so it does not accelerate/decelerate as it completes a revolution ( unlike a U-joint would )

So, what I did last weekend was adding shims ( actually a mitsubishi OEM parts ) to make the first two sections of my driveshaft to have the same angle. Before shimming, the angle was off by about 3 degrees. After shimming, it is within 1-degree of one another. This seems to reduce my deceleration/wub-wub noise tremendeously. Here are the pictures.

I would appreciate it if someone else with decel noise issue give this a try and let us know if this is indeed a fix.

Last weekend, I adjusted my driveshaft angle with a magnetic angle-finder. Note that our driveshafts has 3 U-joints. When two sections of driveshaft are connected by a U-joint, the sections would actually accelerate and decelerate as they complete a single revolution. Therefore it is important to either minimize the angle, or have two neighboring U-joints setup in such a way so that this accel/decel cancels each other out.

More info on this is here.

Also note that the lobro joint on our driveshaft is a constant-velocity joint, so it does not accelerate/decelerate as it completes a revolution ( unlike a U-joint would )

So, what I did last weekend was adding shims ( actually a mitsubishi OEM parts ) to make the first two sections of my driveshaft to have the same angle. Before shimming, the angle was off by about 3 degrees. After shimming, it is within 1-degree of one another. This seems to reduce my deceleration/wub-wub noise tremendeously. Here are the pictures.

I would appreciate it if someone else with decel noise issue give this a try and let us know if this is indeed a fix.