- Dec 6, 2017
Long time lurker first time poster here. So I just finished swapping an IRS from an 03 Cobra into my car and I'm getting some noise from the differential which I rebuilt with new Ford Racing gears and bearings and a Torsen T2 differential. The noise I'm getting is rotational growling/clunking that matches the speed of the car when coasting or decelerating at low speeds. It doesn't matter if I'm in gear with the clutch in or out or in neutral. It doesn't happen when accelerating or at speeds over about 35 MPH, but it makes it at low speed right up until the car is stopped and I can hear it between shifts when accelerating. One interesting thing I noticed is that it doesn't do it at all when rolling in reverse, where it would be clunking up a storm going forward. Also, turning in either direction doesn't make it louder, if anything, turning makes it quieter. So I don't think it is hub or wheel bearings or cv joints, I'm also positive it is not my u-joints or driveshaft as it happens with both my old driveshaft and my new aluminum one. I have checked the pinion for play up and down and back and forth, and there is none. I can't recreate the noise with it up on jack stands, so it seems to need to have a load on the drivetrain to make it. I'm thinking maybe too much backlash? I set it to .010, which should be right in the middle of the suggested range, so I'm having a hard time believing it could be off by enough to make this much noise, but it's the only thing I can think of that makes sense. The gears don't seem to make any other whining or howling noises like I would expect if they were not meshing well. I'm going to pull the differential out and have a look, is there any other mistake I could have made in setting this up that could cause these symptoms?