Lariat AWD 4K EB - 4WD power question

[gp1200x]

What is the mechanism that transfers power to the rear wheels? Since the AWD is not a full lockup of the front wheels to the rear but rather allows a partial transfer of power to the rear wheels how is this actually done? The pto drive for the rear keeps their speed in synch but what is the power transferring mechanism or process? Is it a hydro drive or fluid drive in the tyranny that applies pressure to a pto drive drive gear?

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[Darnon]

Edit: Actually, the below is Ford's older AWD system that's now defunct. The Maverick utilizes AAM's EcoTrac system that can engage/disengage at the PTU as well.

The actual power differential handling is done in the rear differential in what Ford calls active torque coupling. There's a clutch assembly on the input pinion that gets modulated electromagnetically by the AWD module to dynamically control how much torque is applied.

The other components like the PTU assembly that bolts onto the transmission for the rear driveshaft connection is mostly just a dumb hypoid gearset that's coupled to the transmission output.

https://www.transmissiondigest.com/ptu-a-different-kind-of-transfer-case/
https://gearsmagazine.com/magazine/...road-fords-light-duty-all-wheel-drive-system/

 

[FischAutoTechGarten]

The actual power differential handling is done in the rear differential in what Ford calls active torque coupling. There's a clutch assembly on the input pinion that gets modulated electromagnetically by the AWD module to dynamically control how much torque is applied.

The other components like the PTU assembly that bolts onto the transmission for the rear driveshaft connection is mostly just a dumb hypoid gearset that's coupled to the transmission output.

https://www.transmissiondigest.com/ptu-a-different-kind-of-transfer-case/
https://gearsmagazine.com/magazine/...road-fords-light-duty-all-wheel-drive-system/

Thank you for digging up those details!

 

[gp1200x]

Thank you for digging up those details!

Great! Read the articles and never realized there was an electromagnet clutch pack in the rear. My 2013 Escape probably had the same exact setup but I never noticed any power connector to it (must have been pretty well hidden). Pretty simple design once you see how it works.

I haven't looked at this PTU but hopefully this time they added a drain plug and fill plug to it so that it can be serviced - at 50K for me this time. These were disasters on the Escapes from heat destruction and I doubt Ford made any improvements since it looks a lot like my Escape design..

 

[NoVaJimmy]

Great! Read the articles and never realized there was an electromagnet clutch pack in the rear. My 2013 Escape probably had the same exact setup but I never noticed any power connector to it (must have been pretty well hidden). Pretty simple design once you see how it works.

I haven't looked at this PTU but hopefully this time they added a drain plug and fill plug to it so that it can be serviced - at 50K for me this time. These were disasters on the Escapes from heat destruction and I doubt Ford made any improvements since it looks a lot like my Escape design..

They finally learned and have fill and drain plugs on the ptu. That being said I still wouldn't follow their recommended service intervals. Too much heat soaking into the ptu

 

[jc888888888]

What is the mechanism that transfers power to the rear wheels? Since the AWD is not a full lockup of the front wheels to the rear but rather allows a partial transfer of power to the rear wheels how is this actually done? The pto drive for the rear keeps their speed in synch but what is the power transferring mechanism or process? Is it a hydro drive or fluid drive in the tyranny that applies pressure to a pto drive drive gear?

The RDU is the rear differential unit. IT transfers the energy from the driveshaft to the rear tires based on throttle input and traction. It has a series of clutches that handle this.
--Alex Vecerkovic Bozard Ford Lincoln

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