Cruising in second gear I get a clunking noise when I step on the gas. Is this too much slack in the drive shaft? I never experienced this before lowering the car.

 

06 gt by the way.

 

i hear a clunk whenever i go over bumps or deep dips inthe road after lowering my car.

 

From what I've read there is an angle that has to be taken into account when you lower your car. It the angle of the driveshaft as it meet the rear u-joint that attaches to the differential. It's not slack that causes the clunk, but the angle of the shaft in relation to the differential.

Take it to a rear-end specialist (or back to the shop that installed it) and have them check the pinion angle (I think that's what it's called) of the shaft to pinion/differential.

Here's a link. It's for a lift in this case but the same geometry applies.

http://www.4xshaft.com/driveline101.html

 

Your pinion angle is off. You need to use adjustable LCAs when you lower your car to fix this. There's several threads about it over in the "handling" section.

 

I'm the one that started the thread in the handling section. I wasn't sure if the noise was specific to suspension or not.

 

I think yours is the rear axle hitting the bumpstops. Try cutting the bumpstops in half and see if it helps. They are right about it not damaging anything, it's hard to damage the axle tube.

 

check your rear springs, and see if they are rubbing in the tunnel area. I added lca, uca and relocation brackets and my car began to make a clunk/rubbing sounds going in and out of driveways and sometimes just driving. check this thread out that I posted, maybe this will help someone. https://mustangforums.com/m_1996825/...tm.htm#1996825

 

Also, won't relocation brackets help the pinion angle?

 

Not unless they change the angle of the rear axle. I believe they only change the angle of the LCA's.