rear end change out

lamothe1

New Member
May 6, 2008
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Does anyone know what rear ends will interchange with me '99 V-6 Automatic without modifing any brackets. I want to swap it because I feel a vibration in the rear end and I've checked out everything else - had the driveshaft balanced and new universals installed. also what's the R.E. ratio with a Auto & Sticks?
 
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It starts at about 30-35 MPH and is less noticeable at higher speeds like 65, by about 80 it's almost gone. yuo feel it during accelation and if you let up off the gas. The least amoount of vibration is when your not accelating or deaccelating.
 
normally the rearend will cause a noise not a vibration.

when you had the driveshaft balanced. did you check the tranny splines on the output shaft and the bushing?? did you check the splines on the driveshaft yoke??

are the suspension bushings in good condition??

does the vibration change if you change gears?? ie. is the vibration the same at 40mph in 2nd and 3rd gears??
 
What would I check on the tranny splines and the output shaft? I replaced the tail shaft bushing when I had the drive shaft balanced as it was wiped out. The suspension bushings look to be in good condition.
No the vibration goes with the speed of the car & doesn't change if you change gears. I've put the car on jack stands with it in gear & the only place their seams to be vibration is in the R.E.
 
I checked out the tag on the rear end and it says:
top line: S260A
second line: 3 27 75 8M11

does this mean that the ratio is 3:27 to 1?
Seams a little high to me.:shrug:
 
wait man , slow down....

How old is your tires? I would have them rotated and rebalanced. Sounds alot like your tires are out of balance.

But no the GT housing will not directly mount up as you will need all the hardware from the GT. You don't need a nw housing , as i have never heard of a rear end housing needed replaced. If your intent on changing gears I suggest going with 7.5" 4.10 ratio's as they would really wake up your car.

But again , check your tires first and have them rebalanced.....:nice:
 
Yes, the GT's have 8.8 Traction-lok (aka limited slip) rear ends.

The brakes between the GT and V6 are identical.

The housing side changed from 98 to 99. This is because Ford went to a wider stance in the 99+ Mustang so the housing was increased 1.25" in width. That means if you have a 99+ Mustang, you should use a 99-04 8.8 rear end.

The brakes between the GT and V6 are identical. No differences at all.

The GT 8.8 will bolt up to a V6 using the stock lower and upper control arms. The only difference is the 8.8 has quad shocks while the V6 Mustang does not have the body mounts for them. You'll have to find a wrecked GT, cut the quad shock mounts off and weld them to your body in order to use them.

You don't need the quads per say, but you may get wheel-hop without them. Despite what is popularly said on the internet, aftermarket control arms don't always cure wheel hop.

Also, you should look into installing a Gt rear sway bar....even with a stock V6 rear. The bean-counters at ford left it off to save some $$$
 
jgt58

The car had the vibration even when i first bought the car a couple years ago. first thing was I bought NEW Mag. tires & wheels and the vibration didn't change Since then I replaced the tail shaft bushing and I had the drive shaft balanced with new universal joints.
 
What would I check on the tranny splines and the output shaft? I replaced the tail shaft bushing when I had the drive shaft balanced as it was wiped out. The suspension bushings look to be in good condition.
No the vibration goes with the speed of the car & doesn't change if you change gears. I've put the car on jack stands with it in gear & the only place their seams to be vibration is in the R.E.

visually check for scores, rough spots. splines should be square not rounded, check for looseness or binding.


also, have you checked the pinion angle?? the pinion and tailshaft angles need to be the same.