Pretty sure i have the wrong rear end

Stanimal · Jan 5, 2013

So when i bought the car, my buddy was pretty sure it has a 7.5 rear. We discussed it, and came to the conclusion nobody is that stupid to do that. He said he opened the cover and it has a 3.73 gearset, detroit locker, and Moser axles. We really didnt think anyone would dump that kind of money into a 7.5. Well today i went under the car, and sure enough it looks to me to be a 7.5 cover. I pulled the wheels off and it definately has axles, definately has a locker by the way it locks in snow/wet. My speedo is off by the right amount to be 3.73 too. I called the shop that built the car, and they said they didnt know or check what rear was in there, they got the car that way and all they did was rebuild the engine at 120k miles (which ill get into that good/bad part another time), and they also put a new trans in the car same time.

So my question is this. Im planning to build this car, and in my head was the fact i already have a built rear, and a pretty new 5 speed. Apparently the engine already has some goodies so im figuring its making quite a bit over stock as it sits, even tho it doesnt have the supporting mods to make the REAL power. Should i be worried my rear is going to grenade itself? Should i be looking for a 8.8 RIGHT away? Do i have time to build my spare 9" and get it cut, and everything welded on i need to bolt it in? Or should i say f it and hope the 7.5 holds being somewhat stronger then stock with all the goodies it has?

sweet94GT · Jan 5, 2013

I, personally, would get an 8 and build it. In the mean time, drive the car the way you want. If it grenades, you'll have the spare. Shouldn't need a 9. I have buddies running 800+ hp with a built 8

MustangChris · Jan 5, 2013

id be stunned if you could get any kind of diffy for a 7.5 other than an OEM unit.... lol.

Stanimal · Jan 5, 2013

im shocked anyone spent money for the stuff. The diff is available for stock rangers im told. The parts are out there, but im dumbfounded as to why someone would bother lol

330CubeGt · Jan 5, 2013

Post pics of the rearend? Did you measure the ring gear when you had the cover off? With the way 8.8s are built there the new 9" uness you have a sub 8 sec car you shouldn't even have a 9" on your mind imo.

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Stanimal · Jan 5, 2013

I have a 9" on my mind because i have a few of them laying around, and could do the machine work and bracket fabing pretty easily. I figured if im going to end up buying axles, ring and pinion, and a locker i might as well do it in a 9" and not even have to buy the 8.8 housing. I didnt take the cover off, yet, just know what i have felt and seen from the outside. My buddy said he had the cover off to see what was inside. Its sub 30's outside and my garage is full with a wrecked 06 mustang and a 03 f350 with a blown trans. no room to do this indoors. Was all i could muster to do the header gaskets while standing in the snow lol

330CubeGt · Jan 5, 2013

F standing in snow to do head gaskets on any car... Well if you can do all your own work a 9" might be worth it if you have time to fab. You should be able to strip all brackets needed from the 7.5" and part out the guts of the 7.5...

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