Can someone school me on what a new diff will provide me (benefits)?

[Seraphitia102]

I'm getting new Ford Racing gears installed on my car to replace the Motive ones that whine. My installer also recommended replacing the diff (i.e. Detroit Locker, Auborn Differential, etc.) and he said that I will gain traction to both wheels at once. I don't quite know what that means, can anyone explain what replacing my old diff will do with a new one?

 

[mixedbreed02gt]

no idea...i get traction to both of my rear wheels when I shut the TCS off

 

[MineralGray02K]

Well if you ever plan on running slicks on the car, then you need an aftermarket trak-loc such as FRPP etc.

It's all about traction

 

[mixedbreed02gt]

Well if you ever plan on running slicks on the car, then you need an aftermarket trak-loc such as FRPP etc.

It's all about traction

please elaborate, I'd like to know more about why?

 

[bdcardinal]

please elaborate, I'd like to know more about why?

the FRPP one is just a stock center out of an explorer...

if you want to do more road racing type driving, you should consider the Torsen diff. Maximum Motorsports sells TR-R's for a reasonable price.

 

[the98stang]

I'm getting new Ford Racing gears installed on my car to replace the Motive ones that whine. My installer also recommended replacing the diff (i.e. Detroit Locker, Auborn Differential, etc.) and he said that I will gain traction to both wheels at once. I don't quite know what that means, can anyone explain what replacing my old diff will do with a new one?

The stock differential is a trac-loc, meaning both wheels are spinning at once. If you upgrade to a 31 spline differential you can upgrade your axles making them stronger. This allows for more hardcore burn outs and slicks at the track. Ford trac-loc's are dirt cheap and hold up just as good as the more expensive Auburn/Detroit units.

 

[GettinThere]

...to replace the Motive ones that whine. My installer...

A question comes to mind. Will the same mechanic that installed the Motive gears install your new FRPP gears?

 

[Kurgan]

The differential just controls how the power from your engine is distributed to each of your rear axles. Different types of differentials have different behaviors.

Open differential (what the V6 Mustangs generally have) just transfers power to both wheels equally under normal operation, but when one wheel slips, the other gets very little of the power (one-wheel-peel). So all of the power is transferred to the wheel or axle with the least amount of resistance.

Limited slip (Posi-Traction, Trac-Loc, etc. -- all brand-name Limited Slip products) work very much like the open differentials, but use spring-loaded clutches to help transfer power to the non-slipping wheel to keep both wheels turning under power. The clutches can get worn and lead to one-wheel-peels. The clutches can be replaced with a rebuild kit.

Locking differentials come in both manual and automatic locking mechanisms. These have a ratcheting mechanism that allows each axle to turn at different speeds (e.g. when turning), but when traveling in a straight line locks the two axles together to get full power equally to both axles. The locking mechanism can be manual (e.g. press of a button), or automatic. The ratcheting noise is audible and noticeable.

A spool doesn't allow any differential speed between your axles. Both axles turn at the same rate all the time. This is great for going in a straight line, but when you're turning, the wheels need to turn at different speeds. Turning with a spool in the rear end causes your tires to spin a bit on the pavement as you turn, making noise as it happens.

 

[BobHyatt]

The stock differential is a trac-loc, meaning both wheels are spinning at once. If you upgrade to a 31 spline differential you can upgrade your axles making them stronger. This allows for more hardcore burn outs and slicks at the track. Ford trac-loc's are dirt cheap and hold up just as good as the more expensive Auburn/Detroit units.

Actually the stock differential is _not_ a traction lock (we are really talking about the carrier here anyway). Ford uses a traditional clutch-type carrier. The two rear axles are locked together thru a set of disks/pads that can slip. They use a spring to press the pads together, which controls the "locking" between the two wheels. However, if you put the car in neutral, and raise one rear wheel, you might be surprised how easy it is to break that locking friction and spin that one wheel.

BTW the ford limited slip is _not_ as strong as auburn, et al. The ford carrier is dirt cheap, and as usual, you get what you pay for. After a year (or less) of hard use, it will act just like an open rear end as the clutches will be slipping so bad they are ineffective...


Better carriers (auburn pro, etc) have much stronger springs, and a much better clutch mechanism (cone), which provides a much better lock between the two axles, still allowing them to slip when going around corners.

traction-lockers mechanically lock the rear axles under heavy torque load from the pinion gear, but they can "slip" when going around corners (but not accelerating very hard) to avoid excessive tire wear. newer flavors of these are very quiet (older versions made a lot of noise going around corners).

The ultimate is a pure spool where the carrier becomes a solid piece connecting the two axles to the ring gear, no slipping possible. Not good for street. Great for track.

The stock clutch system (talking rear end here) is very weak. The bigger the rear tires, the more likely you are to get a 1-wheel burnout which is no good for launching.

If you don't run at the strip, there's no advantage to swapping this out at all... And doing so will increase rear tire wear a bit as it is harder to make the clutch slip, resulting in scrubbing off rubber as you go around corners.

 

[Seraphitia102]

Well if you ever plan on running slicks on the car, then you need an aftermarket trak-loc such as FRPP etc.

It's all about traction

I am running slicks now lol.

Edit:
Actually, I'm using Nitto DR's. Not sure if the Nitto Drag Radials are still considered "slicks."

 

[Seraphitia102]

A question comes to mind. Will the same mechanic that installed the Motive gears install your new FRPP gears?

No a different one will

 

[Seraphitia102]

Actually the stock differential is _not_ a traction lock (we are really talking about the carrier here anyway). Ford uses a traditional clutch-type carrier. The two rear axles are locked together thru a set of disks/pads that can slip. They use a spring to press the pads together, which controls the "locking" between the two wheels. However, if you put the car in neutral, and raise one rear wheel, you might be surprised how easy it is to break that locking friction and spin that one wheel.

BTW the ford limited slip is _not_ as strong as auburn, et al. The ford carrier is dirt cheap, and as usual, you get what you pay for. After a year (or less) of hard use, it will act just like an open rear end as the clutches will be slipping so bad they are ineffective...


Better carriers (auburn pro, etc) have much stronger springs, and a much better clutch mechanism (cone), which provides a much better lock between the two axles, still allowing them to slip when going around corners.

traction-lockers mechanically lock the rear axles under heavy torque load from the pinion gear, but they can "slip" when going around corners (but not accelerating very hard) to avoid excessive tire wear. newer flavors of these are very quiet (older versions made a lot of noise going around corners).

The ultimate is a pure spool where the carrier becomes a solid piece connecting the two axles to the ring gear, no slipping possible. Not good for street. Great for track.

The stock clutch system (talking rear end here) is very weak. The bigger the rear tires, the more likely you are to get a 1-wheel burnout which is no good for launching.

If you don't run at the strip, there's no advantage to swapping this out at all... And doing so will increase rear tire wear a bit as it is harder to make the clutch slip, resulting in scrubbing off rubber as you go around corners.

The differential just controls how the power from your engine is distributed to each of your rear axles. Different types of differentials have different behaviors.

Open differential (what the V6 Mustangs generally have) just transfers power to both wheels equally under normal operation, but when one wheel slips, the other gets very little of the power (one-wheel-peel). So all of the power is transferred to the wheel or axle with the least amount of resistance.

Limited slip (Posi-Traction, Trac-Loc, etc. -- all brand-name Limited Slip products) work very much like the open differentials, but use spring-loaded clutches to help transfer power to the non-slipping wheel to keep both wheels turning under power. The clutches can get worn and lead to one-wheel-peels. The clutches can be replaced with a rebuild kit.

Locking differentials come in both manual and automatic locking mechanisms. These have a ratcheting mechanism that allows each axle to turn at different speeds (e.g. when turning), but when traveling in a straight line locks the two axles together to get full power equally to both axles. The locking mechanism can be manual (e.g. press of a button), or automatic. The ratcheting noise is audible and noticeable.

A spool doesn't allow any differential speed between your axles. Both axles turn at the same rate all the time. This is great for going in a straight line, but when you're turning, the wheels need to turn at different speeds. Turning with a spool in the rear end causes your tires to spin a bit on the pavement as you turn, making noise as it happens.

Thanks so much guys. That was a lot of useful information

 

[mransr]

if you're upgrading the diff, you probably should go ahead and upgrade to 31-spline axles...

no sense getting a super-strong diff, only to break an axle the first time you get great traction

 

[GettinThere]

No a different one will

 

[blubullett]

I agree go to bigger 31 spline axles. If you are on a budget you can get the ford racing version. By the way Mr. Hyatt the ford unit is a trac-loc. Your explination about diffs is great but call ford and tell them you want a new diff and you get a tracion lock. You are right it is not a locker, its a limited slip, but it is called a trac-loc.

 

[bdcardinal]

exactly, i was gonna point out hte the ford unit is a trac-loc unit.

 

[BobHyatt]

I agree go to bigger 31 spline axles. If you are on a budget you can get the ford racing version. By the way Mr. Hyatt the ford unit is a trac-loc. Your explination about diffs is great but call ford and tell them you want a new diff and you get a tracion lock. You are right it is not a locker, its a limited slip, but it is called a trac-loc.

Don't really care what they call it. It doesn't "lock". It "slips". Limited-slip is the correct term. And it is not worth buying from them either, there are several much better clutch setups available, plus true locking carriers including Auburn's real locker that is quiet on the road but locks up completely under load.

The S-spring on the ford clutch pack is just way too weak unless you only use stockish street tires. The effort required to break the clutch grip and let one wheel turn without the other is just too low to be useful with anything but stock power and stock tires, and even then it will have a fairly short life if used much at the track.

 

[deftsound]

theres really no reason to upgrade unless you plan on having some serious power to the wheels in the near future necessitating the need for slicks

 

[Mustang5L5]

If this is mostly a daily driver with occasional track use...the stock limited slip diff is fine

 

[blubullett]

The labor to install gears is the same as the labor to install gears, a new diff (go to buyfordracing.com for the cheep one) and new axles. Axles are like 200 bucks and the 31 spline ford diff is the same cost as the stock one. I wouldnt replace the stock diff with another stock one unless you started doing one wheel burnouts.