russde

2013 SCrew Ecoboost 4x4. Today was the third time this has happened.
Early morning, start the truck pull slowly out of the driveway, turn towards our cross-street (4 houses down) still under 15mph roadway is slightly wet from rain earlier in the night. Stop at stop sign, accelerate gently, feel rear wheels break loose because of slick street, INSTANT loss of power, truck creeps forward with grinding noise from front end. Back off the accelerator, noise stops, accelerate again and all in normal.
Truck has 54k on it, I bought it a few months back with 49k.
I've searched but can only find folks describing higher speed grinding and other, different scenarios.

TIA,
Russ

icantdrive55

Not sure what you mean by "instant loss of power" but the noise you describe sounds like the front hubs/IWE system. Tons of threads on here about these--same description, although it wouldn't explain the power loss. The hubs are held out of the engagement position by vacuum, which is maintained by the vacuum booster reservoir and a check valve in-line with the hub actuators. Typically located on the driver side near the top of the firewall. When the valve goes bad, it allows the hubs to partially engage as a result of a drop in manifold vacuum when you accelerate. Part is cheap--around $8 from most parts stores--and very simple to replace. Don't drive too much/too far with the grinding noise or you'll possibly damage the hubs. If you have the 4x4 system with the 4A position, I'd use that while driving until you fix the check valve--it should keep it from grinding.

TJPlatinumEB

It can also be the traction control system and it applying braking to the front to straighten it out. Mine is 2WD and if the back tires slide and any sway is detected, it will apply brake force to the front wheels independently to stop the sway and fix it.

white08gt

did you turn your traction control off? if not turn it off and see if if it still does it. I am assuming you are in 4 high.

Ssls6

I would replace the IWE check valve. Engine vacuum is highest at idle and drops when you open the throttle plate. You can test this by using 4H and see if it still happens. In 4H the hubs will lock as there is no vacuum on them.