Rear End/differential

Jan 25, 2018
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#1
Hi I have a 2001 3.8L Ford Mustang first 9 of vin 1FAFP4047 I was wondering what I could do in the rear end to safely increase my top speed I heard that the driveshafts are only rated for 120 and under or they explode what else should I replace that can’t handle 140 also what differential do I have and what could I change it to?
 
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wmburns

SN Certified Technician
Aug 14, 2009
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#2
Well........You could always use the rear end from a GT. Try car-part.com for a searchable list of salvage yards in your area for donor parts.
 
Jan 25, 2018
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#3
But how do I know what gear ratio I have to buy and what differential to buy that will be compatible?
 

Hoytster

I don't dare do that to my Knob
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Dec 30, 2002
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#4
But how do I know what gear ratio I have to buy and what differential to buy that will be compatible?
First of all, I believe the "exploding driveshaft" issue was with the 2-peice driveshafts in the newer V6 mustangs and not your 2001 V6.

Concerning your differential, it should be a 7.5" differential with stock 3.27 ratio gears.

If I may ask, why are you concerned with a 140MPH top speed?
 
Jan 25, 2018
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#5
First of all, I believe the "exploding driveshaft" issue was with the 2-peice driveshafts in the newer V6 mustangs and not your 2001 V6.

Concerning your differential, it should be a 7.5" differential with stock 3.27 ratio gears.

If I may ask, why are you concerned with a 140MPH top speed?
Because I can hit 115 (my governed top speed) in the middle of 4th gear so I know it can go higher especially if I used 5 gear so I didn’t want to delete the governor if something was going to explode or become defective by going that high of speed
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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#6
Check your door jam for a sticker, it should give you an axel code, post it here or just google it, that will give you your gear ratio the factory installed and go from there.
 

Hoytster

I don't dare do that to my Knob
10 Year Member
Dec 30, 2002
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#7
Check your door jam for a sticker, it should give you an axel code, post it here or just google it, that will give you your gear ratio the factory installed and go from there.
Pretty sure every 2001 V6, regardless of transmission is an open diff 7.5 with 3.27 gears.