2001 Mustang cobra 4:10 gear swap, now noisy as hell

are you sure its from the center of the car? sounds like someone didnt check backlash and contact pattern when they did the gears, i would just double check the gears, its odd for something to be making noise after gear gear install that isnt because of the gears themself, its possible but just check before you wear them too much to fix

It's actually from the center, rear. It was a lot worse before having the drive shaft balanced, prior to that the noise/ vibration would start between 75-80 mph, now it starts at @90 on the interstate. The noise is more of a cycling, low sounding whum, whum, whum (if that makes sense), and the vibration makes the plastic panels on the inside rear of the car shake and squeak. I was afraid that the whole diff would have to be pulled again, and I think my mechanic is kinda hesitant about doing it due to the labor costs. He wanted to "eliminate" some simpler things first, ergo the driveshaft balancing. I told him point was the damn thing was fine prior to the swap, now it's not, so it has to be something to do with what happened during that time period. ***WARNING TO OTHER CHEAP ASSES*** You get what you pay for, or the lack of what oyu pay for...lol!!! Learn from my idiotic mistake.

2Manystangs said:

yes read my signature line...NEVER let someone who is not a pro do that kinda thing...setting the "lash" is only for the experienced...live and learn

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Well...normally I wouldn't but the guys dad worked as a Master Mechanic for years at Parkway Ford's SVT shop before they closed and they have several drag Stangs and Street Stangs, so one would think...? but thats what you get for thinking huh? I have definitely lived and learned the hard way. I did stop payment on his check though so he's not getting paid for the f up at least.

....so is everyone in agreement that this is more than likely the backlash improperly set? If so would the droning be due to it being set to tight or to loose? Also does anyone have a good tune for the diablo for my car? I would like to get one that is like the pre-set 93 octane tune but also change the speedo to allow for the gears and wheel size (18"), as well as the addition of the CAI. One can set the spark, fan, timing etc manually but I certainly dont feel quailified to change these parameters myself without some professional input....thanks!