Strange problem on my 2007 Sport Trac

[mwhoody]

Hi Guys, I have a bit of a strange problem and a little bit hard to explain.
What my truck does at times is that it seems to free wheel(?)
When I come out of a parking stall and turn to drive out it seem to lung forward. Like I'm turning very slowly and the truck just seems to lung just a bit.
And also while driving down the road at times it seems to disengage and sort of feels like it's free wheeling and then it will suddenly catch and you could feel a slight thud when it catches.
I had my transmission checked and all is well there.
My concern is that it may get worse and cause bigger problems.
The feeling is like the drive disengages and then it catches again.
Like I said it is very hard to explain and it's also hard to duplicate to a mechanic - it just happens at times.
If someone is experiencing this they will know exactly what I'm talking about
This I have to say seems to happen only at slow speeds. Never felt it on the highway, yet.
I'm sorry if I may not be explaining this more clearly.
Thank you

 

[boominXplorer]

Sounds like the transmission is slipping to me.

 

[eppd00]

Seems like there was a TSB for the surging issue at low speeds(parking lots etc.)My 08 does it occasionally when hot. For instance, you park the truck, go where ever for a few minutes, come back out, crank it up, start to drive through the parking lot and it happens. If I'm not mistaken the freewheeling issue is the torque converter, unlocking and locking as you slow down. That from what I understand is normal.
Mine is a 4.6 with a 6 speed.

 

[Tech By Trade]

any chance the 4x4 is engaging because one of the speed sensors is out. Bad wheel hub?

 

[mwhoody]

Ok, I'll check out these suggestions and see what comes up.
I did take it to a transmission shop to see what he has to say. He told me that to him it sounds like something mechanical - not a transmission. He also said that if it was a transmission problem and it started "freewheeling" the motor would rev up.
Thank you for the suggestions
If I ever get this resolved I will post back again
Thank you