laterider

Lol... too wordy yesterday, I got hit with a major bug before the weekend and was lying around sunday bored off my a$$ recovering - man this place is dead on Sunday, good to see most here have a life too!!!

I just built up my 7.5 with the gears & T-lok. The 7.5/8.8 debate is endless too. My 7.5 reasons were mainly: 1) Didn't want to deal with drop shipping the 8.8 rear to the shop (pretty lame reason really, but it could be a headache)
2) I probably won't go F/I, so the 7.5 can handle 300hp, why bother
3) I'll be 45lbs lighter with the 7.5 than the 8.8, I'll be faster than a 3.73/8.8 V6!!! - lol, just a goofy thought

ODDYSEY

The 7.5 has blown at the track from some members who were N/A (meaning less than 250 rwhp).

Also, there have been members running a 7.5 on F/I and pushing 300-400 rwhp and the 7.5 has held fine.

I said I would never go F/I.. I also said I wouldn't mod my car much...

laterider

ODDYSEY - I'm making an assumption, but from your sig, you are Xcharged and running a 7.5 with T-lok/3.73 - if this is correct - how long have you been running this and whats your confidence level at this point?

Also, for those of us just getting into all this, what generally happens when you 'blow' a rear? - I can invision a lot of things, including overreving the engine during the incident, and I'm thinking engine or remaining drive train damage is unlikely. Enlighten us if you will...

ODDYSEY

I have been running my x-charger & 3.73's for a little less than a year? and I have had no issues and I am not worried about it at all.

But then again, I do not go to the track, and I don't do hard launches (often). If it blows it will be a load bang and you won't move anywhere.

Stang-aholic

thanks for the diagram this puts into perspective very well!!

so to do this you have to order the entire rear end kit, or just gears and t-lok. i will definately get a dealer to install, so what do they need?

Ken04

if you're going to the drag strip and launching hard with sticky drag radials on a prepped track I'd put in a 8.8 axle, it's stronger. But unless you're going to do that, or putting out more than 300 rwhp the 7.5 properly set up should be good to go.

Sancho805

all should make note that the weak point in the 7.5 is the posi. its not cheap but you can upgrade the 7.5 with a much better posi than the frpp t-lok and thus eliminate the risk of "blowing your rear".... lol, sounds nasty.

this could be an option for those wanting to beef up their already modded rear without having to purchase an entire 8.8.

ßeaver

Very very newbish questions about to happen.. Please forgive me.

What is the stock rear end on the 2006? 7.5?

Also, I do drive hard, I spin my wheels more often then I don't, I drift corners, I have fun with my car, I like to drive ... happily if you will..

Would upgrading to the 8.8 and 4.10 be a good choice in this case, and, what other things should I do? t-lok, 4.10, 8.8 rear, and then what?

And then something that bothers me.. I am a former 240 guy. my last 7 cars have been 240's, all dohc ka24de engines, hard to break, overreving is fine, you don't break them easily.. With the mustang though, the v6 4.0L, its a SOHC engine, are they known to break easily, warp the heads or blow out the valve cover gaskets or anything? and again, I'm a former 240 guy, so I'm learning all about the mustangs as of a week ago, the 240 sohc's were and are known for blowing the head gaskets and overheating, warping the heads, etc... I don't want to do that with the mustang, so, is there a kit that can convert it to a dohc? or should I do a complete engine upgrade or what?

I apologize if this isn't the place to ask my last question. I just thought, throwing them all in at the same time would be better then making a whole new thread for it.

laterider

You have two choices, this is described for non-dealer install, but read more below if going to a dealer:

1.) Order the desired gears (3.73 or 4.10) and t-lok and have a shop change out your current gears/open diff to the new parts. As Sancho noted - the T-lok isn't the only LSD for a 7.5 rear end, it is a Ford part and I think the lowest cost LSD you will find for a 7.5 - about $200.00 for one. I think I checked into an Auburn LSD for the 7.5 - its double the price or more I believe. Some have also said, maybe you want the SHOP to order any parts - this could assist in a warranty for being 'whine free'

-OR-

2.) Order/purchase a GT 8.8 rear with the desired ratio (i.e 3.73 or 4.10), they are available from sites like newtakeoff and the rear end is setup with the correct flange for a V6. From my research the flange is the only part of the GT 8.8 rear that needs to be replaced, the GT flange will not mate with a stock V6 driveshaft. It needs to be replaced with a flange that people are calling the Cobra Flange (probably used on the CS6???), interesting name it has been given, but really this is probably just a stock V6 flange.. Have a shop install this new rear, or some have said this is not a bad DIY IF you have some reasonable mechanic skills.

Also take note, if a dealer doesn't do the work, you will need a tuner to update the ratio in the PCM.

Stangaholic - I don't know if its common for a dealer to install a new GT 8.8 rear on V6 models, but every dealer is different. Just ask.
Also - I believe someone else on this site had a dealer install 3.73s in his 7.5 V6, and his cost was about $500 more - $1500 total vice the avg $900-950 for getting a gear shop to do it. However this member also stated the dealer install kept everything under warranty.
Just one thing to keep in mind, its always going to cost more for the dealer to do something like this. To some, the peace of mind having the dealer do it is worth the extra $$. If you are going to go with a dealer install, you won't be ordering any parts yourself, just tell them what ratio you want and that you want the t-lok also.

Sancho805

t-lok is NOT the only posi option. just the more affordable posi option.