How To Make A Stronger 7.5

Topic: How To Make A Stronger 7.5 (Read 2771 times) previous topic - next topic

How To Make A Stronger 7.5

April 15, 2014, 05:56:57 PM

Hi guys, I've been researching here and elsewhere and I haven't found too many favorable opinions on the 7.5 rear end. The only performance upgrades I will be doing on my '86 will be the HO Upper Plenum/TB/EGR Spacer swap and probably a "performance" ler on the stock single exhaust. I do like doing the occasional burnout or powerslide and the car may see a few trips down the 1/4 mile. Do you think the stock unit would be sufficient for this? Are there any parts that will make this unit stronger? I don't even care about a T-Lok(I may consider 3.73's in the future), I just want a reliable axle that can withstand some fun.

Thanks.

How To Make A Stronger 7.5

Reply #1 – April 15, 2014, 06:19:28 PM

I think without slicks that 7.5 will handle just about anything you throw at it. Remember, the Mustang didn't get the 8.8 until '86 or so, and the Capri never got it at all...

Traction lock will help it live longer (one wheel peels will chew up the spider gears). There used to be a "girdle" cover available for the 7.5 which added strength, but I don't imagine it added strength to the weak spot. I am no expert on rear ends but if I were to guess I'd say the weak spot in the 7.5 would be its pinion gear and spider gears and shaft.

How To Make A Stronger 7.5

Reply #2 – April 15, 2014, 06:33:02 PM

To hell with trak-lok. Get a full locker, some aftermarket axles, a rear main girdle and be done. The locker I have in mind e is rated to 800 ft lbs of torque. The spider gears are the weakest link. The full locker eliminates them. American Muscle sells a rear girdle for the 7.5 as does LPW.

If I had to do it again I'd go 31 spline instead of sticking g with 28. Other than that I can't complain.

How To Make A Stronger 7.5

Reply #3 – April 15, 2014, 07:37:12 PM

I've never had issues with my 7.5's. The only time I had an issue was when I rebuilt a rear end and took out the carrier and reinstalled it with new crush sleeves and bearings. I didn't get the backlash right or something and it ate up the gears. I've learned to just leave the carrier in place and not change the bearings unless it's needed.

How To Make A Stronger 7.5

Reply #4 – April 15, 2014, 08:56:46 PM

I haven't broken one yet. the v-6 stangs ran them forever, even the.250+ hp ones.

How To Make A Stronger 7.5

Reply #5 – April 16, 2014, 11:18:57 AM

Thanks guys. It sounds like for close to stock power levels I should be good, even with having some fun. From what I read online I'm expecting for the rear to grenade on a hard take off. Lol

If something happens I'll just have it rebuilt stronger. But this is a cruiser so I really don't see a need for an 8.8 upgrade if this axle is sufficient.

How To Make A Stronger 7.5

Reply #6 – April 16, 2014, 11:39:29 AM

You can upgrade cheap by pulling a trac lok and gears out of a ranger

I did it for my buddy with a v6 stang

How To Make A Stronger 7.5

Reply #7 – April 16, 2014, 11:49:15 AM

Quote from: STANG8U;432426

You can upgrade cheap by pulling a trac lok and gears out of a ranger

I did it for my buddy with a v6 stang

Would I have to upgrade the axles if doing this?

How To Make A Stronger 7.5

Reply #8 – April 16, 2014, 03:35:31 PM

There 28 spline you can use your axles

How To Make A Stronger 7.5

Reply #9 – April 16, 2014, 08:19:01 PM

All 2.3 mustangs were also 3:73 gears and traction lock, if your fine with a 7.5". That's what i plan to do later.

How To Make A Stronger 7.5

Reply #10 – April 16, 2014, 09:56:42 PM

Is limited slip the same as trac lock? My 84 Turbocoupe has 3.45 gears and I believe limited slip. I am going to change fluid and seals soon on it.

How To Make A Stronger 7.5

Reply #11 – April 16, 2014, 10:18:16 PM

Yes a trac lok is a limited slip

How To Make A Stronger 7.5

Reply #12 – April 22, 2014, 08:03:03 PM

Each munufacturer had their own name for a limited slip rear end. Ford was Traction-Lok. Chev and GMC was Positraction. Chrysler was Sure Grip.

How To Make A Stronger 7.5

Reply #13 – April 22, 2014, 10:04:12 PM

Quote from: Haystack;432464

All 2.3 mustangs were also 3:73 gears and traction lock, if your fine with a 7.5". That's what i plan to do later.

Not even close to truth.
I can vouch for my '87 2.3/T5 Stang as having an open diff. I'd have to go out to the shop to see the tag on the rear, but I can assure you and anyone else it's nowhere near 3.73. I replaced it with a 3.55 8.8 with trac lock from another Mustang. It does have 3.55 gears...they've been changed, it's stamped into both the ring and the pinion..

When I put that rear into my Sport in 2009, I noticed it was a 3.55 swapped rear when filling it with new diff fluid.

Compared to the anemic 7.5 the 3.55 8.8 makes the "WussStang" haul ass....it'll be MUCH more fun once I get my 5.0 finished and dropped in..doing some much needed shop upgrades while I have free time and a bunch of stuff cleared out.

How To Make A Stronger 7.5

Reply #14 – April 22, 2014, 10:15:04 PM

I've checked 3 or 4 and all I've seen were 3:73 with traction lock. Ill check a couple next time. i hit the yards