My car was built in Sept. and does not have the extra weights bolted on both sides of the rear axle. I heard they started putting them on to stop a vibration. They are mounted right below the springs, they are just 3 pound square pieces of steel. Anyone have any other info on these and how many of you don't have them? Sorry no pics...

 

my '06 didn't have them but my '10 does .
Think i'll remove them..

 

My 07' GT vert (June 06 build) has them.

 

Never noticed a difference with, or without.
I"ll sell you mine(cheap)

 

I thought that those were there just for rail transport or tie downs and that some were just left on , there had been huge debate on TMS before about that.

 

The drivetrains on our cars have interesting harmonic issues. AFAIK, the weights are put on cars that exhibit too much NVH. It's not every car or even by build date. If this is in fact the case, I'm not sure how they figure out which cars get it and which don't.

 

It's possible that the gear ratio might determine the need for the weights. Lower gear sets will tent to want to vibrate a bit more because of how the gears are cut. cars with 3.55's might have the weights, while cars with 3.31's don't.

That's why they started putting the dog bone on the IRS pumpkin in 03 when they switched to the 3.55 gear set.

That's just my theory though. I could be way off base.

 

I believe my 08 CS did have them. Took them off however when the BMR suspension went on.

 

I have the weights, 3.31's, and the 18" Bullitt rims on my GT/CS.

 

I don't have them. Yay.


What do I win?

 

They are for axle whine and noise dampening. There is a TSB that says to add them first. Some cars have them from factory obviously

 

Nor do I if Gary get a prize I sure as He l l want one too !

 

From a Ford engineer that worked on Bullitt:


Rear Axle Damping Weights...?

Hey folks, have any of you removed your bolted-on weights from the rear axle? If so, did you notice any difference in whine or vibration...?

I'm thinking it may be a good way to drop a few pounds of unsprung weight (I've read they weigh around 3-5# each), but don't want to do it if it'll create any problems. I can live with a little more axle whine, if that's all they're for.

Anyone here removed theirs?

*****y lower control arm bracket axle masses

They are there to attenuate axle whine. If you currently notice axle whine in your car in the 45-65mph range, it may increase a bit if you remove the masses. They are one part of a fairly extensive package engineered to address axle whine on the s197 platform.

 

We removed them off of Leo's 06 GT when we installed the relo brackets.

I did not have the weights and mine's also an 06.

 

This man speaks the truth. This is the real reason. Ford builds their vehicles in a way, for safety, that creates a tuning fork effect on a lot of parts. The 2004+ F150s were notorious for vibrations from harmonics. I actually had my car at the dealer and they asked if I wanted them to add the weights to the axle to get rid of a whine at 50 mph as per the TSB. I politely said don't worry about it but maybe I should of got them in case I needed a good paper weight for out in the shop.

 

Both my '08 Bullitt and '09 KR have the same rear end with 3.73s, and both had the weights... Now neither has them. I was happy to remove a total of 9 pounds unsprung weight from each car by unbolting them, and doing so caused no problems.

 

My '08 CS doesn't have them. Built 1/08.

 

yeah but now your front to rear weight distribution/balance is off