Hi all
was wondering if anyone can help
I have a grind noise coming from under my truck 2008 HD f150
it comes from the transfer case of the awd
have checked the iwe solnide and it’s working and gets vacuum but there is no power coming to it when I start the engine.
any help would be helpful , seen as here in holland there are no dealers and very few garages know anything about American cars

 

I will assume your truck works the same as in USA... This is called 4 x 4 drive, not AWD.... You have IWE on each front wheel. The front wheels are ENGAGED when the motor is off.. When you START the motor and have vacuum, the pistons in the IWE pull the engagement OFF and you are in 2 x 4 , 2 wheel drive ... To get to 4 x 4, you turn the **** and it shuts off the vacuum and the front IEW ENGAGE the wheel... If you have noises , it is probably the IWE not moving full stroke.

If you know the IWE is working properly, then the TRANSER Case has an electric motor that shifts IN and OUT of 4 x 4 and LO to HI gear. The motor can be weak, or things dragging inside.. You can unbolt the motor and pull it off the transfer case.. You can manually shift the forks IN and OUT ( inside) to see if you get more travel or sticking.. you can electrically test the motor with it setting on the ground under the truck.

This all assumes your truck is the same as USA . YOu should have a **** on the dash that says ........ 2 wheel drive, 4 wheel LO, 4 wheel HI ..... I assume you do not have a AWD position ?

 

explain how IWE works..

https://www.ford-trucks.com/forums/8...then-some.html

 

do you have the grinding in the 2 wheel drive and the 4 wheel drive **** positions, or just one ?

 

The OP has a single speed TOD transfer case. The front end is full time locked. The grinding is from the clutch being worn out. The transfer case needs a rebuild. Was this truck towed with the wheels on the ground?

 

Guys thanks for all the tips
the truck is the same as in the USA
transfer motor is functioning as it should .( or should I say I hear it move when I flip the switch to 4x4 ans light appears in the dash )
noise is nearly constant if I put it in 4x4 .
truck has never been towed
problem is it’s a awd and 4 wheel drive no option on the dash for 2 wheel drive the only options are awd or 4x4
hd edition , the solenoid is on the drivers side and the vacuum line coming into it has Vacuum the ine coming out goes to the transfer case under the truck behind the automatic gear box this line has no vacuum when I start the truck .
have tested the solenoid of the truck and it opens when I apply power .( so it seem to be working) the problem is it doesn’t get any power when I start the truck thus not allowing vacuums to the transfer case , have checked for fuses and relays but can seem to find any and the few I found relating to 4x4 seen all ok .
( there are no lines coming from the solenoid to the front hubs and on the front hubs where these are connected in a normal 2 wheel 4x4 truck on the HD version they have a rubber cap on it )
maybe I should say the noise is not constant at low speed you don’t hear it also not at constant speed , it’s only when I’m driving above 35 miles or more and only starts makeing a grinding noise when I release the gas peddle if i push the gas in again and the and the truck picks up a bit of speed the noise goes away as it also does if I slow back down to under the 30 mph

 

( there are no lines coming from the solenoid to the front hubs and on the front hubs where these are connected in a normal 2 wheel 4x4 truck on the HD version they have a rubber cap on it )

Well, it sounds like Ford390 has you figured out........ if you have NO IWE, then it has to be the transfer case.

 

Can you please post a pic of the AWD/4x4 selector? I've never heard of this on an F-150. Also, why would there be a position for AWD and one for 4x4? That just doesn't make any sense whatsoever.

Also, a pic of your hubs, where the vacuum lines go please, and a pic of the transfer case where the vacuum lines are.

A video of the truck when making the "noise" would also be helpful. From your description, it sounds like the front hubs are engaged all the time. On flat ground/pavement, where this is no tire slip this is exactly what engaged hubs would do.

Did you buy this truck used? Perhaps it was modified to run with engaged hubs full time. Why someone would do that I do not know, as the truck was not designed for that.

 

There was an AWD/4x4 option for a few years (2006-2008?) with AWD and 4x4 High (no low range). The Lincoln Mark LT had the same option.
I sure can't seem to find anything about repairs though...

 

Did the front end of the AWD have IWE parts that were LOCKED due to no vacuum hoses ? We have an EXPLORER with AWD and 4 x 4 .......... The AWD lets the computer control the front wheels / drive shaft when it notes slip......... the 4 x 4 is your OVER RIDE of the computer control system.

 

Steve, I’m just guessing here, but I suspect this is (sorta) similar to my Navigator. The front diff and front hubs are always engaged. When in AWD (I think of it as A4WD i.e., A-utomatic F-our W-heel D-rive) where the TOD (Torque On Demand) electronic clutch in the transfer case is not engaged until wheel slippage is detected. The unengaged clutch allows the front and rear driveshafts to rotate at different speeds, but when wheel slippage is detected the TOD electronic clutch is duty cycled to gradually lock the front and rear driveshafts together. When the operator shifts to 4x4, the TOD clutch gets duty cycled at 100%, effectively locking the front and rear driveshafts together. Driving in 4x4 on solid surfaces, something has to give during windup, and apparently it was the TOD clutch that gave out.

 

With the help above I think I know what the problem is .
done a bit more checking onder the car ,
transfer case is AWD TOD from Borgwarner model number 4406-42 vehicle manufacturers number 8L34-AB .
ford390 hit he nail on the head , so I’m looking for a replacement or will have to rebuild it.
there comes the problem, although I have found suppliers of replacement cases on line all in the USA ( in Holland there is no one with the part ) the cost are any where between 700 and 1100 dollars but then comes transport and the bigger problem that they want the old case back or otherwise you pay an extra 400 dollars. And then I seem to find a good few 4406 models but none with -42 or manufacturer’s number 8l34-AB . So the question is will another 4406 fit alsnog as it’s AWD model .
considering the costs I think a re build will be a better option , but yet again have found 4406 kits nut none that specific say it’s for a 4406-42 MF 8l34-AB , so does any one know if ther rebuild kits are standard to model numbers .
thanks ones avail to all that have taken time to reply .

 

Sorry forgot to ask is there any way to disconnect the front wheel drive or awd while I’m waiting for replacement or rebuild kit .
of corse I still want to be able to drive safe and not cause any more damage ,
takes anywhere between 1 and 2 week to get stuf in from the USA

 

Well, Ian, I don't know how its made, but you said you think you have IWE wheel ends that are capped with a rubber plug.. Probably setting too many years, but if you put VACUUM on the capped lines, it should pull the IWE out of engagement.. That's probably wishful thinking..... You could remove the front drive shaft and keep the front end from turning... That is not good on the clutch, but you said it is failed anyway, so should not hurt it more.

 

putting vacuum on front iwe is a possibility but think that won’t stop the clutch from kicking in when it feels slip on the back wheels
the ideal solution would be to stop the clutch from kicking in when it feels slip and in return puts power to the front ( engaging AWD),
can this be done by removing a relay or fuse ?
essentially what I’m thinking of is just letting the vehicle run as a 2wd