ive got a problem and it's not good

[03FX4]

soo i parked at the pizza place one day and i got back in my truck to get home and i start driving and i hear a thunk type noise. coming from the front left wheel area. as i continue driving i hear a quick THUNKTHUNKTHUNKTHUNK really fast noisethen it stops. so i pulled over to see if there was anything major going on and nothing i could see. soo i drove home and it didnt happen again.

the next day which is today i tried driving downtown and i hear one thunk as i start rolling out of the driveway, then the same THUNKTHUNKTHUNKTHUNK really fast started happening down the road, so i turned around and came home. idk what is going on.

as i pulled in my check engine light came on. i tried really really slowly letting out the clutch to start barely moving.. id roll a little bit then stop due to some type of resistance going forwards and in reverse, when i bypass that resistance is when i hear the thunk noise.

the only thing i thought of was somehow getting a rock or something stuck somewhere, i went through some mud and shitty areas the other day. that's the only thing i could think of. I havent taken anything apart yet...

any ideas on what's going on?

 

[Randy960]

I say check your lugnuts, but I don't know why that would put the check engine light on

 

[martin]

Check the driveshaft u/js first, if they are ok I would suspect the crosspin has come loose and is banging on the end of the pinion gear. Metal particles can get on the sensor ring and cause the speed sensor to get erronous signals.

 

[Fx4wannabe01]

He describes it as a 'thunk'.....repetedly...I really don't think this issue he's having is U-joints. U joints would be a high pitched hollow squeek, not a thunk. Also, check engine light won't come on if it's the ABS sensor in the rear diff....it would throw an ((ABS)) light. If it was differential related, it wouldn't be on-again-off-again like he's describing.


OP, is the vehicle in question the '03 Fx4? How many miles on the vehicle? Is it lifted? Would'nt hurt pulling the front wheels off the truck and having a look-see...could be possible something got lodged between the wheel and the rotor. I've had that happen before. But you do describe it as a thunk. I had similar thunk like sounds when my front driveshafts rear joint took a shit. The whole front end felt like it was wobbling apart. Thank you Ford for a piss poor design when used on a lift application.