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Transmission/ PTU modification


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Basically looking for anybody that has more information / ideas regarding the transmission and PTU.

 

I started researching and found a reference to JTEKT, a Japanese company. Sounds like they are making the PTU, rear diff, and RDU. Also sounds like the clutch pack that puts power to the rear is in the PTU. Does that all sound correct?

 

So in looking for potential upgrades I emailed Level 10. Turns out they do have a trans upgrade option for this unit, but nothing for the PTU. The guy did say in an email he could be interested some R&D if there was enough interest.

 

Before I continue researching / pestering people I want more info on this rear end unit. Specifically does anybody know if the unit is strong enough to handle more? If somebody comes out with a clutch/PTU that will put more power to the rear how much will it hold?

 

Any info would potentially help us all. I am going to use what resources I have to try and get more info on the system and its capabilities. If I can find anything good or bad I will pass along.

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Nice work Paul! I don't know very much about the ptu or the rear dif on our cars. I know the PTU is electronically controlled from looking at schematics on fordparts.com. But the units are sold complete, no internal shown or sold. And I have examined mine closely when change fluid in PTU, the control module on PTU is quite large and has a motor on thats larger then the starter motor and engine. Me a Darrell have discusses looking into modding the PTU and he said he recall seeing something in factory service manual saying that Torque was adjustable from 0-100% I had asked him to please research further "hint hint!" lol But I know he is a busy guy. I will see want I can pull up on my buddies garage computer.

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Crash that explains a lot! But leaves a lot of questions... Still dont know what the rear diff can handle and if/how that PTU can be adjusted or altered. I am going to keep digging with the resources I have' date=' maybe something will turn up.[/quote']

 

HMMM, this one has got me thinking, is the PTU the same as in the 2011 and newer explorer? We happen to have a 2011 Explorer and you are able to change the way the system works through the dive select control. On the dash stack you can display the intelligent AWD system. This display shows in real time where the power is being sent as you apply the gas. When you select sand for instance the system disables the Traction control and sends more power to the rear wheels (more power is sent to the rear than the front) I have tested this in the snow. Now all this is great, but I wonder if the PTU in the SHO could be made to change like the Explorer. That would be fun to say the least, even if say you could send 60% to the rear forced for a while ;).

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The Explorer is set like a FWD correct? I am sure the systems are different but could the PTU's interchange? I havent found anything on what the rear diff might handle. That said I have a feeling it could handle a lot. That plus I remember reading a post way back that said the AWD system including the rear diff could handle a crap load, but the trans was in question.

 

Supposedly it is just a "clutch" inside our PTU determining the 150 ft lbs. Why couldnt somebody build a clutch to put 200 ft lbs? or more? It sounds simple but somebody needs to R&D it and find out.

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The Explorer is set like a FWD correct? I am sure the systems are different but could the PTU's interchange? I havent found anything on what the rear diff might handle. That said I have a feeling it could handle a lot. That plus I remember reading a post way back that said the AWD system including the rear diff could handle a crap load, but the trans was in question.

 

Supposedly it is just a "clutch" inside our PTU determining the 150 ft lbs. Why couldnt somebody build a clutch to put 200 ft lbs? or more? It sounds simple but somebody needs to R&D it and find out.

 

This site has a quote regarding the PTU, it doesn't say that it's the same PTU as the Explorer but it's made by JTEKT.

http://www.fordfusionforum.com/index.php?/topic/5190-jtekt-awd-itcc-system-electronic-control-unit-supplier/

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I'm in the camp that believes that the rear has got to be able to handle more than 150ft-lbs of torque. That's Honda 4cyl torque levels. Considering the raw mass of our cars and the manner in which everything else is so overbilt on them I just don't think it makes any sense at all that the rear diff could be so frail. If the torque distribution can be computer controlled that would be fantastic. If it's manually limited by the clutch mechanism then that's going to take a little bit more work. It'll be worth it though to even get another 50-100ft-lbs back there considering how much torque they've made with those upgraded turbos!

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The Explorer is set like a FWD correct? I am sure the systems are different but could the PTU's interchange? I havent found anything on what the rear diff might handle. That said I have a feeling it could handle a lot. That plus I remember reading a post way back that said the AWD system including the rear diff could handle a crap load, but the trans was in question.

 

Supposedly it is just a "clutch" inside our PTU determining the 150 ft lbs. Why couldnt somebody build a clutch to put 200 ft lbs? or more? It sounds simple but somebody needs to R&D it and find out.

 

That link says JTEKT can have 295-1475 ft lbs in the system. And that they are Dyna Rear ends, I know Dyna wouldn't build a pansy rear end.

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The thing is there is a separate box for programming the system and I do not know if aftermarket can reprogram. My guy at JTEKT is doing some checking for me.

 

Also, he is not sure how much the system can hold because Ford uses there own half shafts.

 

I am working on this diligently and hope to have more info later.

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Mike you are awesome! It would be nice to confirm or deny the 150 ft lbs. Based on the fact that we are all spinning the fronts it is probably accurate or close to it. The Explorer can put more power to the rear so why cant we?

 

If you find out there is a way to adjust this it will feel like Christmas, heck just the possibility feels like Christmas!

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Way to go Mike! I can see it now.... we will all be at the track by the spring drifting like mad men! not to mention launching like a beast! I do have a friend that works at a local assembly plant putting together the MKT (they also assemble the Flex, MKX and Edge). I haven't spoken to him in some time. I will give him a call and see if he can shed any light on this. I believe that the MKT has the same AWD as the Flex (which is similar to the SHO)? I'll see if he knows how the programming of system is handled at the plant.

 

Jeff

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This is directly from Ford Repair Manual. The rear diff is what controlls torque with a clutch that enguages it looks like it is designed to slip and apply more when slippage is detected it is PCM and controlled though the ATC (active torque coupling) and the 4x4 module. My tech said rear diff is small in design and probably not designed for large amounts of torque but not set in stone info. It may be possible to have a program to change the amount of torque percent delivered to ATC but he said it may cause a chatter when turning like a spool or possitrac diff. When I get some time I will monitor the percent of torque with normal driving from my car that is delivered just to see how it changes with acceleration. Hope this info is helpfull!

 

 

DESCRIPTION AND OPERATION

Rear Drive Axle and Differential

The rear drive axle consists of the following components:

• Dished circular flange

• Full-time Active Torque Coupling (ATC)

• Aluminum housing with steel housing cover

• Matched ring and pinion

• Conventional open differential

• Rubber bushing isolated mounting points

• Cover-mounted axle vent

The rear axle drive pinion receives power from the engine through the transaxle, Power Transfer Unit (PTU), driveshaft and ATC, and is always engaged.

The All-Wheel Drive (AWD) system on this vehicle is equipped with a bar-coded rear axle to reduce the tolerance of electrical current-to-torque delivered

by the ATC. The 4X4 control module uses this bar code information to match the clutch characteristics of the ATC with the desired output torque. The

pinion gear then rotates the differential ring gear, which is bolted to the differential case outer flange. Inside the differential case, 2 differential pinion gears

are mounted on a differential pinion shaft, which is pinned to the differential case. These differential pinion gears are engaged with the differential side gears

to which the halfshafts are splined. The halfshafts are held in the differential case by a driveshaft bearing retainer circlip that is located on the inboard CV

joint stub shaft pilot bearing housing. When each halfshaft is installed, the driveshaft bearing retainer circlip engages a step in the differential side gear. As

the differential case turns, it rotates the halfshafts and rear wheels. When it is necessary for one wheel and halfshaft to rotate faster than the other, the faster

turning differential side gear causes the differential pinion gears to roll on the slower turning differential side gear. This allows differential action between

the 2 halfshafts. The pinion seal and the differential halfshaft seals are the only serviced components of the rear drive axle. There are no stub shaft bearings

in the differential housing and the differential housing cover uses a silicone sealant rather than a gasket. If other components of the rear drive axle or the

ATC are worn or damaged, a new axle assembly must be installed.

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Lesterg69,

 

Great info and can you find out if it is a separate PCM unit that programs the clutch? Is the 150 lb ft torque number thrown around correct? JTEKT informed me the clutch can handle 590 lb ft of torque.

 

Also, I have no problem if we can reprogram for the track and change back for normal driving.

 

Thanks for your help!

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