Traction Concepts LSD Conversion Kit

[802SHO]

Still aching to know what model our rear gear assembly actually is!
It sounds like the rear may be a little more custom in regards to fitment as compared to the front? More of a "take material off the gears until they fit with the LSD module". Can you confirm @802SHO ?

Traction Concepts told me our Dana rear diff does not use/match the Dana LSD’s they currently have. It is a Dana rear diff as shown on the ring gear. 41:14 is the ratio. Same ring gear in my 2010 that’s also in another members 2016. Just different dates but both are 41:14. And bc these things bolt in, you can swap them around pretty easy if you needed to. TC installed it for me and their service charge is $150. I believe they generated a part number for it and let me check if it’s now on their site. https://www.tractionconcepts.com/Ford-Taurus-Sho-Ecoboost-AWD-Rear-LSD-Kit-p/tcxflm2804.htm

Yup^^^^! I also did a search of Ford Taurus sho on TC’s site, got 6 listings that popped up. This company is on the ball! Just bc you flex or MKS guys don’t see a rear diff offering doesn’t mean it won’t fit, please everyone, don’t be timid to send them an email and ask…..they are extremely active in adjusting their product line on and off their website.

 

[BweegN]

Be curious to see if there is any differences on the 3:16 vs 2:77. Looks like we have a Dana product we need to name for ourselves!

 

[802SHO]

Be curious to see if there is any differences on the 3:16 vs 2:77. Looks like we have a Dana product we need to name for ourselves!

I don’t believe there is. All the magic happens in the front diff for ratio 3.16 or 2.77. The PTU steps it down and the RDU steps it up so they are 1 to 1. Correct me if I’m wrong @Ecoboost_xsport

 

[Rutim]

That's a fair amount taken off the front spider gears. Has anyone blown spider gears in the front diff? This is usually the first component to fail in a diff. For sure going to get the rear LSD for my SHO tho!

 

[802SHO]

That's a fair amount taken off the front spider gears. Has anyone blown spider gears in the front diff? This is usually the first component to fail in a diff. For sure going to get the rear LSD for my SHO tho!

Personally I’ve never heard of anyone having a front diff problem. Still has a good contact patch on the teeth to engage the axle gears.

 

[Bluezone]

That's a fair amount taken off the front spider gears. Has anyone blown spider gears in the front diff? This is usually the first component to fail in a diff. For sure going to get the rear LSD for my SHO tho!

I don't know if very many spider gears have been damaged. The front differential is very large for FWD, over 9 inchs. So I guess you can brag that you have a 9-inch Ford differential in your Taurus. LOL. Spider gears are used slightly less though when you have a LSD.
While searching 4 a LSD for the 5F55, I came across an external electronic LSD used by the GM equivalent. Unfortunately this won't work for our transmission, it only locks one side of the differential. So the spider gears actually received more work and it weighs a lot. I made a posting about this elsewhere.

 

[BweegN]

Now we gotta sick @802SHO back on raybestos to finish off our driveline ;-)

 

[Ta2dResqr]

That's a fair amount taken off the front spider gears. Has anyone blown spider gears in the front diff? This is usually the first component to fail in a diff. For sure going to get the rear LSD for my SHO tho!

I would guess part of what helps save the front diff is the fact that out of the hole, the power is sent more to the rear. This takes the initial load off the gears. Then as the car gets going, it switches to more power to the front. If you activate the AWD Gauge in the IPS with ForScan, you can watch how the power is divided. It was kind of fun a couple times. Now it is just another screen to skip over lol.

 

[Bluezone]

I would guess part of what helps save the front diff is the fact that out of the hole, the power is sent more to the rear. This takes the initial load off the gears. Then as the car gets going, it switches to more power to the front. If you activate the AWD Gauge in the IPS with ForScan, you can watch how the power is divided. It was kind of fun a couple times. Now it is just another screen to skip over lol.

I don't know how much actual torque is sent to the rear differential on launch. The size of the rear differential is not huge and it takes a small amount of time for the coupler to lock up through mechanical ramp advantage and speed differential. So not instantaneous.
My MKS is a 2010, so I don't have the availability of the all-wheel-drive Gage. What is the gauge showing the torque split is? Max should be theoretical 50/50. That is depending on conditions. 0 traction on front wheels and 100% rear still would not give 100%, because of coupler clutch slip and electronic safety limits. So torque potential would be spent as heat build-up in the coupler.

 

[Ta2dResqr]

I don't know how much actual torque is sent to the rear differential on launch. The size of the rear differential is not huge and it takes a small amount of time for the coupler to lock up through mechanical ramp advantage and speed differential. So not instantaneous.
My MKS is a 2010, so I don't have the availability of the all-wheel-drive Gage. What is the gauge showing the torque split is? Max should be theoretical 50/50.

Unfortunately, it is a bar graph not a number display. I also can't find much in the FoMoCo manual. It just says "increases".

 

[Bluezone]

Okay, I was debating whether or not I was going to make a separate post on how people fundamentally think the all wheel drive system works on our cars. But I kind of think it's time for me to make this post. This will take a while to write up so stay tuned in. Just because you've read it once don't expect it to remain the same. I will be editing it to clarify and explain points better.

 

[FiveLeeter918]

Okay, I was debating whether or not I was going to make a separate post on how people fundamentally think the all wheel drive system works on our cars. But I kind of think it's time for me to make this post. This will take a while to write up so stay tuned in. Just because you've read it once don't expect it to remain the same. I will be editing it to clarify and explain points better.

I ain't got time for that, type it out in Word and publish it when ready, haha. OR at least use varying text colors to denote your updates :-D

 

[Bluezone]

I would like people to think in different terms of how the all wheel drive system functions and effects traction performance.

Imitation is the sincerest form of flattery.

Nice but not quite true. Now the system we use is in essence a modified version of the haldex all-wheel drive. It's a part-time system. It's intended to be a complimentary traction assistance. Simple way of saying this is that it aids/adds to the traction available to the front wheel drive system. This is an important part to consider. This is also was slightly misleading as I will explain further on.
JTEKT designed the RDU clutch coupler to mimic the action of a viscous coupler in a all wheel drive system. From their explanation and performance graphs. It shows that this is not a perfect analog.

We don't need no F'n brakes.

The next part is going to sound a little bit on the strange side, but please follow along and consider it.
Now that the 2013 and up, all wheel drive system, uses the anti-lock brake system to achieve torque vectoring and simulated limited slip differential action.
Now how this is achieved is clever, but slightly counterproductive. The brakes are applied to any wheel experiencing traction loss. This slows the rotation speed of the offending wheel. Now if your cornering while this is happening, it will aid steering turn in and send engine torque back through the system in the differential and then through the spider gears. So in some ways it's slightly self-defeating. It's making the spider gears work harder and producing heat through friction on the brakes. Plus loading up the CV joints and axles.

Wait what!!

Now next you need to understand how the PTU, RDU and Viscous Coupler operate and effect the system.
Now the pinion gear meches with the ring gear and turns the differential housing. This explains the first step of the power/work flow out of the transmission.
Now it appears there are two main flow paths for work flow. This is misleading though. I will explain.
Now the first and "number one path", is via the spider gears to the axle gears. Which divide the work flow according to rotation speed.

But wait, there's more.

Now this is where things get a little confusing, but I want to change how you think about this. Now the second power flow path doesn't exactly do what you think it is doing.
To explain this you first have to understand that the PTU is directly splined to the front differential. From this direct connection, power is fed through a series of driven, idler and a driven ring gear. A step up ratio by the PTU pinion gear then increases rotation speed to roughly 2.93 times (but .002 slower than differential to unload clutch) the rotational speed of the front differential. This is transferred by the driveshaft to the input of the viscous clutch on the RDU. The clutch activates through the powering of an electromagnet which engages the clutches when there is a differential in rotation speed between drive shaft and the pinion gear on the RDU. This allows the ball and ramp cam system to energize and provide clutch pressure.
As a side note, notice that the wheels. This acts to provide increased reaction speed of the ball and ramp system. More sensitivity.
It's also the (VERY CLOSE TO THE) rpm as needed by the RDU ring and pinion gear set ratio.

Okay I think I've got that.

Now remember those spider and Axle gears in the front differential? They are free to differentiate as needed. Guess that's why it's called a differential. So from the factory the only way to moderate front axle speed is the the traction control system application of brake Force to the offending wheel. Not so fast though. The use of the all wheel drive system, in essence, is also there to moderate front differential rotation speed. Remember the PTU is splined directly to the front differential. Is a secondary power flow path. It acts to match drivetrain rotation speed to the road speed. Strangely it works in a different manner, but to same effect as using brakes to slow down spinning wheels. In this case it provides forward thrust instead of drag via braking force/rotational restrictions.

So what does all this mean and what's the meaning of life?

So what I would like you to think, when you think about the all wheel drive system. Is that it's an analog, just like the simulated limited slip function is an analog LSD via the brake system. Sometimes systems do unusual things or have unusual effects.
What I'm trying to say is we have essentially a front wheel drive system with helpers. The rear wheel drive portion of our all wheel drive system has limited abilities. If you really want to accelerate more quickly. Concentrate a lot of your efforts on the front part of the drivetrain.
So the front l.s.d. is essentially the most important addition to the drivetrain. It helps to directly moderate front axle rotation speed differences. The all-wheel-drive portion only accentuates that ability. It cannot by itself overcome lack of traction at the front end. Hope this all makes sense and the answer is 42. https://www.independent.co.uk/life-...life-the-universe-and-everything-2205734.html

 

[Bluezone]

I would like people to think in different terms of how the all wheel drive system functions and effects traction performance.

Imitation is the sincerest form of flattery.

Nice but not quite true. Now the system we use is in essence a modified version of the haldex all-wheel drive. It's a part-time system. It's intended to be a complimentary traction assistance. Simple way of saying this is that it aids/adds to the traction available to the front wheel drive system. This is an important part to consider. This is also was slightly misleading as I will explain further on.
JTEKT designed the RDU clutch coupler to mimic the action of a viscous coupler in a all wheel drive system. From their explanation and performance graphs. It shows that this is not a perfect analog.

We don't need no F'n brakes.

The next part is going to sound a little bit on the strange side, but please follow along and consider it.
Now that the 2013 and up, all wheel drive system, uses the anti-lock brake system to achieve torque vectoring and simulated limited slip differential action.
Now how this is achieved is clever, but slightly counterproductive. The brakes are applied to any wheel experiencing traction loss. This slows the rotation speed of the offending wheel. Now if your cornering while this is happening, it will aid steering turn in and send engine torque back through the system in the differential and then through the spider gears. So in some ways it's slightly self-defeating. It's making the spider gears work harder and producing heat through friction on the brakes. Plus loading up the CV joints and axles.

Wait what!!

Now next you need to understand how the PTU, RDU and Viscous Coupler operate and effect the system.
Now the pinion gear meches with the ring gear and turns the differential housing. This explains the first step of the power/work flow out of the transmission.
Now it appears there are two main flow paths for work flow. This is misleading though. I will explain.
Now the first and "number one path", is via the spider gears to the axle gears. Which divide the work flow according to rotation speed.

But wait, there's more.

Now this is where things get a little confusing, but I want to change how you think about this. Now the second power flow path doesn't exactly do what you think it is doing.
To explain this you first have to understand that the PTU is directly splined to the front differential. From this direct connection, power is fed through a series of driven, idler and a driven ring gear. A step up ratio by the PTU pinion gear then increases rotation speed to roughly 2.93 times the rotational speed of the front differential. This is transferred by the driveshaft to the input of the viscous clutch on the RDU. The clutch activates through the powering of an electromagnet which engages the clutches when there is a differential in rotation speed between drive shaft and the pinion gear on the RDU. This allows the ball and ramp cam system to energize and provide clutch pressure.
As a side note, notice that the drive shaft is rotating roughly three times faster then the wheels. This acts to provide increased reaction speed of the ball and ramp system. More sensitivity.
It's also the same rpm as needed by the RDU ring and pinion gear set ratio.

Okay I think I've got that.

Now remember those spider and Axle gears in the front differential? They are free to differentiate as needed. Guess that's why it's called a differential. So from the factory the only way to moderate front axle speed is the the traction control system application of brake Force to the offending wheel. Not so fast though. The use of the all wheel drive system, in essence, is also there to moderate front differential rotation speed. Remember the PTU is splined directly to the front differential. Is a secondary power flow path. It acts to match drivetrain rotation speed to the road speed. Strangely it works in a different manner, but to same effect as using brakes to slow down spinning wheels. In this case it provides forward thrust instead of drag via braking force/rotational restrictions.

So what does all this mean and what's the meaning of life?

So what I would like you to think, when you think about the all wheel drive system. Is that it's an analog, just like the simulated limited slip function is an analog LSD via the brake system. Sometimes systems do unusual things or have unusual effects.
What I'm trying to say is we have essentially a front wheel drive system with helpers. The rear wheel drive portion of our all wheel drive system has limited abilities. If you really want to accelerate more quickly. Concentrate a lot of your efforts on the front part of the drivetrain.
So the front l.s.d. is essentially the most important addition to the drivetrain. It helps to directly moderate front axle rotation speed differences. The all-wheel-drive portion only accentuates that ability. It cannot by itself overcome lack of traction at the front end. Hope this all makes sense and the answer is 42. https://www.independent.co.uk/life-...life-the-universe-and-everything-2205734.html

Any omissions or suggestions that need to be addressed in this? I already see you a few things that need to be added.
One these items is my math on the PTU gear ratio is not working out so far.
I think the better explanation of how the rear coupler is needed as well.

 

[Ecoboost_xsport]

I don’t believe there is. All the magic happens in the front diff for ratio 3.16 or 2.77. The PTU steps it down and the RDU steps it up so they are 1 to 1. Correct me if I’m wrong @Ecoboost_xsport

That is correct, the differences between the 2.77 and 3.16 happens in the transmission and the ring gear of the front differential. The carrier assemblies (where the TC LSD would reside) are identical.

PTU steps ratio down, sends power to RDU and its stepped back up accordingly, making the ratio between the PTU:RDU 1 to 1. So the 3.16, 3.43, 2.77, etc is all done with the front. The rear simply emulates what the front is doing.

 

[Ecoboost_xsport]

Now we gotta sick @802SHO back on raybestos to finish off our driveline ;-)

Damn, Andrew! Gettin all the credit!!!! Haha.

Not to toot my own horn, but I'm gonna toot my own horn...

The Raybestos thing was me...

 

[Bluezone]

That is correct, the differences between the 2.77 and 3.16 happens in the transmission and the ring gear of the front differential. The carrier assemblies (where the TC LSD would reside) are identical.

PTU steps ratio down, sends power to RDU and its stepped back up accordingly, making the ratio between the PTU:RDU 1 to 1. So the 3.16, 3.43, 2.77, etc is all done with the front. The rear simply emulates what the front is doing.

Yes, thank you, I understand that. Just that the math of the PTU gear ratios hasn't been working out to match the expected roughly 2.93 of the RDU. I've asked 802SHO to count gear teeth. So I can try to correct my counts via pictures. Unfortunately i threw my old one away before checking. Lol

 

[Ecoboost_xsport]

I don't know how much actual torque is sent to the rear differential on launch. The size of the rear differential is not huge and it takes a small amount of time for the coupler to lock up through mechanical ramp advantage and speed differential. So not instantaneous.
My MKS is a 2010, so I don't have the availability of the all-wheel-drive Gage. What is the gauge showing the torque split is? Max should be theoretical 50/50. That is depending on conditions. 0 traction on front wheels and 100% rear still would not give 100%, because of coupler clutch slip and electronic safety limits. So torque potential would be spent as heat build-up in the coupler.

Under normal conditions, only about 30% is transferred to the rear on launch. The bar graph (which sucks with only 4 bars of resoltuon) indicates this.

The Ford Explorer has a terrain management system that allows 50/50 on launch in Sand Mode, but the shift tables suck. Designed for low speed, high torque....like you'd need in sand, lol.

I've tried starting in Sand Mode, then switching mid track, but the car doesn't like that and simply won't shift. The ability to change the front to rear lockup doesn't reside in the PCM, which is why no tuner has been able to access it to change it.

The best that Brad (AJPTurbo) was able to do for me is transfer over the shift tables from Normal Mode (that I race in) to Sand Mode...which seems to have worked, but I haven't had a chance to test it at the track yet.

If you observe the percentage of front/rear lockup within Forscan, you can see an actual percentage. I've been unable to identify what PID this is as I've been dying to be able to datalog this within SCT.

If anyone knows how to extract a PID from a Forscan value, I'm all ears.

 

[Ecoboost_xsport]

Yes, thank you, I understand that. Just that the math of the PTU gear ratios hasn't been working out to match the expected roughly 2.93 of the RDU. I've asked 802SHO to count gear teeth. So I can try to correct my counts via pictures. Unfortunately i threw my old one away before checking. Lol

Which teeth count do you need? Front or rear diff? I have that info.

 

[Ecoboost_xsport]

Okay, I was debating whether or not I was going to make a separate post on how people fundamentally think the all wheel drive system works on our cars. But I kind of think it's time for me to make this post. This will take a while to write up so stay tuned in. Just because you've read it once don't expect it to remain the same. I will be editing it to clarify and explain points better.

I've already written and posted this