31 Splines Question

[chefcaleb]

So I am having my rear end upgraded. Some issues with the car point to the need of a new posi unit. Since I am considering going with a supercharger some time down the road, the garage that I am using suggested making my rear end "bulletproof" as he put it. Meaning that it will accommodate the added power of the supercharger and be upgradeable in the future, should I choose to do so. Anyway, we were discussing a 31 spline upgrade vs the stock 28 spline. He was saying that it isn't completely necessary to go up to the 31 splines so I chose to stick with a Detroit locker diff for a 28 spline to keep the cost down. He is also doing a reinforced cover with the upgrade bolt kit and c clip eliminators.


So my question is, are 31 splines completely necessary? If you feel they are, what are the reasons? Is the Detroit locker a good choice. I want to be able to have good turning capabilities as this is my daily driver but have the added benefit of locking the tires for the torque as I am wanting to do some weekend racing with the local circuits, in the future. Just want to make sure I made the right choice. The guy at the garage assured me the 28 splines are very capable and it was refreshing not to have someone try and push a more expensive product on me. Anyway, thanks for any input.

[sailsmen]

Are you going to Drag Race with slicks or drag radials?

Are you keeping the stock torque converter?

What RWHP&TQ are you anticipating?

[MOTOWN]

The Axle package your looking to build is going to be nothing short of a nightmare for DD use , a Detroit locker is the worst choice for a DD (other than a spool) C clip eliminators are not meant for street use and leak consistently , all you need if you want a strong 8.8 are 31 spline axles an Auburn pro series diff and whatever gearing your going to run , don't overthink it with a Bunch of unneeded parts.

[crownvic05]

The Axle package your looking to build is going to be nothing short of a nightmare for DD use , a Detroit locker is the worst choice for a DD (other than a spool) C clip eliminators are not meant for street use and leak consistently , all you need if you want a strong 8.8 are 31 spline axles an Auburn pro series diff and whatever gearing your going to run , don't overthink it with a Bunch of unneeded parts.



Said by a pro.

[chefcaleb]

Are you going to Drag Race with slicks or drag radials?

Are you keeping the stock torque converter?

What RWHP&TQ are you anticipating?



I will be keeping street tires. I know drag radials would be best, but bear in mind I am not wanting to go full on race mode with this car.


My anticipation for the RWHP would be in the mid 500s. He says he could get me to the mid 600s but I like to remain conservative.


I'm not sure about the torque converter at the moment.

[RubberCtyRauder]

you will need a built motor and a large centri or a twin screw to get to mid 500rwhp. stock motor generally can handle 425 range. A true Detroit locker will chirp and hop on turns

[chefcaleb]

The Axle package your looking to build is going to be nothing short of a nightmare for DD use , a Detroit locker is the worst choice for a DD (other than a spool) C clip eliminators are not meant for street use and leak consistently , all you need if you want a strong 8.8 are 31 spline axles an Auburn pro series diff and whatever gearing your going to run , don't overthink it with a Bunch of unneeded parts.



I think the reason he showed me the Detroit locker was because I specifically told him I wanted a happy medium between the stock diff and a spool. Seems Detroit locker fits the bill. But from what I am seeing you all say, that may not be a good choice. Does the Auburn pro series offer good torque management like the locker is known for? I've seen many people say they love their locker for daily driving, then there are others saying they don't. Seems the one that love the locker are on 4wd Jeeps and what not. Perhaps that is the difference?


Yeah, I am reading about how the c clip eliminators leak. Some say they haven't had issues, some say they do. I will talk to him about it. I know he was saying that it offers more safety so the c clip "nub" doesn't wear down and the axle fall off from the extra torque. But I don't want the leaking issues either as this is my DD. Anyway, thanks for the input.

[Blown3.8]

Well here are my thoughts. If you are replacing the diff you might as well upgrade the axles too. They aren't that expensive. Especially if you want 600 hp someday. And I would not go with the Detroit Locker if you are planning on driving thru twisties. Instead go with the Detroit Tru Trac. That is a slick diff and no clutches to wear out.

[Gryphonzus]

I ran for several years pushing 480HP to the wheels on a stock block stock rear end. I finally broke the carrier so I upgraded to a Mustang carrier and 31 spline axles. I looked at it this way if they are going to be working on the rear end I am going to upgrade everything. If you cannot afford to upgrade everything why not drive it as is until you need to fix it? Just my two cents.

[chefcaleb]

So other than being capable of handling the more horsepower, does 31 spline offer any other benefits?

[Gryphonzus]

No they are just more capable of handling the horsepower.

[chefcaleb]

I ran for several years pushing 480HP to the wheels on a stock block stock rear end. I finally broke the carrier so I upgraded to a Mustang carrier and 31 spline axles. I looked at it this way if they are going to be working on the rear end I am going to upgrade everything. If you cannot afford to upgrade everything why not drive it as is until you need to fix it? Just my two cents.





Yeah good point. The axles aren't that much more... maybe a couple hundred. I posi for a 31 spline though is also more. But I agree, why not do everything. I just want to make sure I'm not going to a 31 spline needlessly. That's my concern. I also want to make sure I get the best diff for my needs. I want the extra grip on the road, but I also am tired of sliding out of control when I turn... wet roads make it even worse. That's why I looked into this to begin with now, rather than later. I am hearing a whine/grind sound when I turn and I am skidding a lot when I turn and barely hit the gas. What's funny is I am already driving like I would have to with a locker. I already have to take turns rather slow due to the slipping. Anyway, I am talking with him about redoing my order.

[Lowndex]

you will need a built motor and a large centri or a twin screw to get to mid 500rwhp. stock motor generally can handle 425 range. A true Detroit locker will chirp and hop on turns

Will the Auburn unit not chirp and hop on turns?

[RubberCtyRauder]

Will the Auburn unit not chirp and hop on turns?

no, it is a limited slip

[RubberCtyRauder]

if you hear noise then possible axle bearing going bad and your clutches in trac lok could be worn, so its good you are going thru rear and looking at upgrades

[sailsmen]

I am happy with what's in sig - my 31 Ford Spline Axles & Detroit Truetrac, 4:10 Ford Racing Gears

[chefcaleb]

So as I research the c clip eliminators it seems like it depends on the install and the brand used. They seem to add a safety benefit too. But you all are saying that that's not true? I see some say they leak but a lot of others say they use them on their daily drivers without any issue. Anyway, I like the idea of a safety factor, but not the whole leaking bit... And those who are saying not to get it and the Detroit locker have personal experience with these items?

[fastblackmerc]

So as I research the c clip eliminators it seems like it depends on the install and the brand used. They seem to add a safety benefit too. But you all are saying that that's not true? I see some say they leak but a lot of others say they use them on their daily drivers without any issue. Anyway, I like the idea of a safety factor, but not the whole leaking bit... And those who are saying not to get it and the Detroit locker have personal experience with these items?

"C" clip eliminators do provide some security but IMHO that is overridden by the leaking or potential for leaking. A majority say don't use them on a street driven vehicle.

DO NOT get any type of locking rear. I don't know how much clearer we can make this, unless you and your passengers like to hop around corners with a lot of banging noises. My son had a Camaro that had a locking rear - for the track - and it was horrible, just horrible driving in anything but a straight line.

[fastblackmerc]

So as I research the c clip eliminators it seems like it depends on the install and the brand used. They seem to add a safety benefit too. But you all are saying that that's not true? I see some say they leak but a lot of others say they use them on their daily drivers without any issue. Anyway, I like the idea of a safety factor, but not the whole leaking bit... And those who are saying not to get it and the Detroit locker have personal experience with these items?

"C" clip eliminators do provide some security but IMHO that is overridden by the leaking or potential for leaking. A majority say don't use them for a street driven vehicle.

DO NOT get any type of locking rear. I don't know how much clearer we can make this, unless you and your passengers like to hop around corners with a lot of banging noises. My son had a Camaro that had a locking rear - for the track - and it was horrible, just horrible driving in anything but a straight line.

[chefcaleb]

Well I switched to 31 spline axles and I went with the Auburn ected diff. That way it will be a true limited diff for my daily driving and I'm able to switch to locked when I want while driving. Seems to be the true best of both worlds. I had time to research it and those who race say the ected is a very good diff. Anyway, thanks everyone for warning me about the locker.

[justbob]

I’m hard as hell on mine with a manual trans and my plain Jane Ford Racing 31 spline axles and diff are just fine..

Might I also suggest a diff stud kit and a solid pinion spacer.


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[fastblackmerc]

+1 on the stud kit & solid space. I'd also recommend a new cover with bearing supports.

[chefcaleb]

+1 on the stud kit & solid space. I'd also recommend a new cover with bearing supports.

Yes, I'm getting a reinforced cover just as you suggested in my question to you about 4.10 gears. It has the ability to add oil without taking off the the cover. Looks like one nice piece of equipment. Now, the stud kit and solid space, not sure about that. Geeze, things just keep getting piled on. Tis the life I suppose.

[justbob]

Yes, I'm getting a reinforced cover just as you suggested in my question to you about 4.10 gears. It has the ability to add oil without taking off the the cover. Looks like one nice piece of equipment. Now, the stud kit and solid space, not sure about that. Geeze, things just keep getting piled on. Tis the life I suppose.



The solid spacer and the stud kit are relatively cheap and pretty much sums it up for extras after the diff and axles.


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[chefcaleb]

The solid spacer and the stud kit are relatively cheap and pretty much sums it up for extras after the diff and axles.


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Yeah, I realize that now. Got them ordered too.

[GreekGod]

I strongly disagree with a few suggestions on here:

1) the Eaton Detroit Trutrac is what you want - forget about any differentials with clutches (unless you want to replace the clutches on a regular basis).

I have been driving my MM for many years with a Detroit locker. It took a while to get used to it, but I have not had any problem with it - some minor noise issues and occasional clanging. People who hear it think it is breaking or coming apart. It has never "hopped around" and it does not "chirp and hop on turns" - that's what happens with a spool!

I probably should have gone with the Trutrac, but I wanted the strongest differential available - the people at Eaton will recommend the Trutrac.

2) a solid spacer makes replacing the pinion seal a simple R&R of the flange, without affecting the pinion preload

3) 31 spline shafts are a minimum for performance use - 28 spline are not even to be considered. Ford went with 31 spline shafts with the Panther platform from 2005 and up

4) studs for the main caps and an aluminum cover with pre-load bolts can only help - get them

5) 4.10 gears are the best for what you want

6) C-clip eliminators are for racing only - not for street driving with a daily driver - if you want a safer way to go, have the axle ends replaced with 9" ends (and custom axle shafts) -- 9" Ford axle tube housing ends - the big bearing "New Style Torino ends" (3.150" o.d.)

Moser has a nice "Hobby Stock" 33 spline package (and probably Strange does too)
re:

http://www.moserengineering.com/hobby-stock-circle-track-axle-package.item