Fox T-Bird/Cougar Forums

General => General Fox T-Bird/Cougar Discussion => Topic started by: baylensman on March 31, 2005, 11:27:30 AM

Title: quickie, 7.5 rear
Post by: baylensman on March 31, 2005, 11:27:30 AM
is there a posi unit for this rear?
what ratio is best for the aod?
what kind of hp can it handle?

thanks walt
87 lx
Title: Re: quickie, 7.5 rear
Post by: foxford on March 31, 2005, 12:04:43 PM
Yes there is a posi for the 7.5, but for the money you would be much better off going and getting an 8.8 that already has posi out of a turbo coupe or an sn95 stang, especially since the 7.5 is a very weak unit that can't handle any real power at all. which ratio is best for the AOD depends on what you want to use the car for, for general all around use, I like 3.73s with 4.10s still being feasable on a daily driven car, but that's pushing it.
Title: Re: quickie, 7.5 rear
Post by: Tbird232ci on March 31, 2005, 12:05:20 PM
there is a posi unit, us ford boys call it traction lock though, some cars came factory with it, but you can buy them new

best ratio, it depends on your driving style, and where you drive, but generally, 3.73's

horsepower, depends also, if you go to the track on slicks, itll break quicker than youd like under big power, but on street tires, under normal traction (or lack there of), itll hold up pretty well, its the initial launches that usually hurt them
Title: Re: quickie, 7.5 rear
Post by: armyguy298 on March 31, 2005, 01:53:19 PM
Auburn makes a limited slip. The link is:

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1189&prmenbr=361

$376 bucks...
Title: Re: quickie, 7.5 rear
Post by: shame302 on March 31, 2005, 02:32:03 PM
the tbird sports came factory with a trac loc 7.5" rear diff. they can handle some abuse. mine is fine but they tend to fail. ive seen one in a v8 ranger take 3 years of powershifting. like tbirs232 said, its the launches that toast them. you cant realy launch a v8 ranger. it usually happnes at the track with the added traction. if you are making a trip to the bone yard save yourself the time and money and get an 8.8.

as far as ratio, 373s are decent for an aod

as far as how much hp..if your engines a stock 3.8 or 5.0 SO it (7.5 trac loc) should handle those all day long with an AOD.
Title: Re: quickie, 7.5 rear
Post by: Tbird232ci on March 31, 2005, 02:38:58 PM
you can get a ford traction lock for the 7.5 cheaper than the auburn
Title: Re: quickie, 7.5 rear
Post by: armyguy298 on March 31, 2005, 03:08:27 PM
cool!  :D

I just punched some numbers in to see what was out there.
Title: Re: quickie, 7.5 rear
Post by: SirChirpAlot on March 31, 2005, 03:42:55 PM
My rule of thum is when going some kind of up grade go with whats better for the long run.  U can dump money into the 7.5 if u wish its your money.
But u still have a 7.5  and u will be spending dubble the money when it fails.

For the price of getting parts and having them put into the 7.5 u can get a 8.8 that has amost all u need right off the bat.

8.8 out of a TC with 373 gives u the gear u want the posi U want.
Will be cheaper then getting parts for 7.5 and having them put in.
If u look around u can get used lower arms and box in your uppers.

Now u have something much better for less.
Title: Re: quickie, 7.5 rear
Post by: Go Roush on March 31, 2005, 04:54:07 PM
The 7.5 is available like every one said, but I also agree the 8.8 is a much beter choice with 3.73's.  Around here a whole unit out a junkyard is $400.
Title: Re: quickie, 7.5 rear
Post by: vinnietbird on March 31, 2005, 07:47:44 PM
I've got a 7.5 locker in mine with the 3.45 gears.I like it so far.It was only $50.
Title: Re: quickie, 7.5 rear
Post by: Ifixyawata on March 31, 2005, 09:35:17 PM
Thought I'd also throw out that '83-'86 T-birds came stock with 7.5" 3.45:1 Traction-Lok rears with Quad-Shocks.
Title: Re: quickie, 7.5 rear
Post by: shame302 on March 31, 2005, 10:32:18 PM
ill sell mine (7.5 trac loc) for 75 plus shipping ;)
Title: Re: quickie, 7.5 rear
Post by: SirChirpAlot on March 31, 2005, 10:50:33 PM
400 is crazy,
87 TC rear end goes for 200 250 here,
If u go to pull it your self yard 100 bucks.
Title: Re: quickie, 7.5 rear
Post by: vinnietbird on March 31, 2005, 11:30:23 PM
I probably would've went for an 8.8 if it were available in the beginning,but this was my only Locker option.I have an 8.8 in the garage now with 3.55 gears.I'll get it in someday.No hurry.Right now I'm focusing on getting the H.O. finished and in the 'Bird.