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should i rebuild or replace

  • rebuild the 7.5

    Votes: 2 11%
  • replace with the 8.8

    Votes: 16 89%

replacing the rear end vs rebuilding the 7.5 on my 1999 Mustang v6

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15K views 38 replies 11 participants last post by  DGS2vGT  
#1 ·
Hey guys ive got a 1999 mustang V6 shes got 235000 somethin miles on her ive already replaced the transmission, but the rear end is making a whining noise and i had a guy who does alot with mustangs tell me its the carrier berrng going bad, Ive had my car up on a car lift and took the cap off and felt inside the rear differential and theres metal shavings. I went and bought the rebuild kit from AA for 75 but then the shop told me it would cost at least 300 for him to replace all the berings and rebuild it with the kit ive got. On the other hand i know at the nearby pull a part they have a 1995 mustang GT with the 8.8 rear end and im thinking its going to be better and cheaper to upgrade to the 8.8 rather than rebuild the 7.5 that came with the car, i believe my car had 3.27 gears and the 8.8 one on the 95 will have 3.08 how will these compare and will the 8.8 bolt on to my car or is there anything i need to replace?? Does anyone have a guide on doing this?? Thanks again guys
 
#3 ·
8.8 is stronger and if it is in good shape an easy swap. You still run the risk of the clutches in the diff being worn out and need replacing. As for the 3.08 vs the 3.27's its a toss up. Not sure if you would notice much change.
 
#4 ·
Thanks man so its a easy conversion? is there anything ive got to change out if i switch to the 8.8?? Also other than feeling for metal shavings in the differential is there anything else i should look for when buying a used rear end??
 
#5 ·
Many people swap gears out so be sure to pop the cover off and look to see what gears are in it. If they are diff than stock you will need a Speedo Calibrater or a tuner to correct it.
 
#6 ·
ok where would i look to see what the gears are?? what would be the best gear ratio for a v6 in your opinion for someone whos not doing any drag racing but mostly long trips? id like to keep my good gas mileage
 
#7 ·
No one has mentioned that the 94-98 rear is narrower by almost an inch. It's a direct bolt in but your rear tires are going to sit slightly inward of their current position unless you run a wheel spacer. That being said I'd still swap to the 8.8 if there are ANY future plans of a powertrain upgrade. If it's going to retain the V6 just rebuild the 7.5.
 
#13 ·
this, i had to run spacers

pulled my rear from a 2002 gt myself and some one switched it and i didnt notice until it was half in the car
 
#9 ·
I don't know if the 95 had ABS or not. Yes, the 1 inch will make a difference but a spacer will correct it.
 
#11 ·
Well if i went and replaced the gears then i would have to have it rebuilt which would again set me back, all the rear ends im finding are for the 94-98 models, this s becoming a real headache and all the local junk yards want outrageous amounts for their mustang rear ends. I did however find a guy about 3 hours away with a 95 gt complete 8.8 rear end with 3.55 gears in perfect shape he said he will sell me for 200, would you guys advise going this route on my car?
 
#15 ·
Its not a big deal just put the spacers on..they slip on when you put your wheel on ..id just rebuild it though cause itll.be less hassle and no work for you and it seems like your lost so i wouldnt take it on and you can swap gears while in there and itll make the car quicker
 
#19 · (Edited)
Yea no problem man you can realy tell when someone takes pride in their car. But here are the differences ive learned between them.
"79-93 Mustangs use a 57 inch wide rear axle. 94-98 Mustangs use a 58.5 inch wide rear axle. 99 and newer Mustangs use a 59 7/8 inch wide rear axle. Lincoln Mark7 LSC, SVO Mustang and Fox Body Saleens use a 59.5 inch wide rear axle"
and this as well which has me concerned
"99-04 lower control arms! THAT IS IMPORTANT! 96-98 control arms are the same on the side that bolts to the axle but the side that bolts to the car is smaller. You need a 14mm not a 12mm. If you put 96-98 Lower control arms in it, it will have to much play and be catostphic!
All upper control arms are interchange 79-04 so anyones will work"
 
#23 ·
"99-04 lower control arms! THAT IS IMPORTANT! 96-98 control arms are the same on the side that bolts to the axle but the side that bolts to the car is smaller. You need a 14mm not a 12mm. If you put 96-98 Lower control arms in it, it will have to much play and be catostphic!
All upper control arms are interchange 79-04 so anyones will work"
This is true. However, all you have to do is replace the chassis side bushing and bushing sleeve with a 99-04 bushing and bushing sleeve and you can then use the larger bolt. Easy fix.
 
#20 ·
Hahaha, yeah i really do take care of her. Thanks!

I'd personally look for one thats '94-'04. If you use a '94-'98 just run the spacer. The reason why i had to was because i used s197 rims. The fronts are fine, it was just the rears that needed that 1.5" spacer. :yes
 
#21 ·
Rear ends out of a 99-04 in my area go for $150. If I had been on this site when I had my 2001 v6 mustang and could ask some questions I think I would have just done that. I put new bearings, T-lok, 3:73 gears, seals, fluid and all in my 01 v6 stang and it cost $680
 
#26 ·
wheew that shure is alot for them spacers :confused: for that i might as well spend a lil more and just find the 99-04 gt rear. Im going to make some more calls tommorrow. Did find a guy who totaled his gt hes got a rear end wants 500 for it though and its got 410 gears in it and thats probably more than i need since i do alot of long distance driving and that would kill my gas mileage :(
 
#28 ·
yea i doubt he will take that for it, there was one guy near by who had a 02 GT whos been giving me the runaround for a week and finally called me back and told me he got the car and has the rear end and its got 2.73 gears in it and the least he will take is 500 on it so im pretty much screwed here :/ I think im just going to have to get the 98 and put it on.
 
#32 ·
Im sure its been stated stock 8.8>modified 7.5
 
#35 ·
your wheels will sit 1/4 of an inch further inside your wheel well
 
#37 ·
Isnt noticable...Its only a half inch total shorter width of the whole car