Hey all,
I have a '98 Expy 4x4 and have always noticed that the front-end makes a little grinding-type noise in 2WD while slowing down to a stop. It sounds as if the front is still locked as if in 4WD but not as loud. At first I thought it was stuck but when I put the truck in 4WD you can tell it definitely 'just' kicked in. (noise gets normally louder) I also thought it might have been my tires because they had cupped and made that rhythmic out-of-round noise. I recently bought new Michelin tires and can now hear it's definitely the front-end. (Same type of noise though, sort of grinding but rhythmic which obviously slows down as the truck slows down)

I'm not familiar enough with the front-end to know if it's coming from the differential (?) or maybe the transfer case.

I also have a problem sometimes with the truck staying in 4H. I have the electronic shift shift with: 2H-AWD-4H-4L. Last month in the snow I put it in 4H and it kept switching back and forth between AWD and 4H - ie. it wouldn't stay in 4H. This happened last year in the snow also and seems to taper off as the transmission warms up.

BTW, is AWD supposed to be silent because I can definitely hear it when it's running. Same type of gear noise as 4H but a little quiter.

Any ideas of what to try? Should I change any fluids?

Thanks!

 

Aycardus,

The front differential of the Expy is always engaged. There is no vacuum activated disconnect. If you are hearing a grinding noise I would check the Rotors then the Bearings.
Does the noise go away when you press on the brakes? Is it louder?

Regards

Jean Marc Chartier

 

JMC - you are right about 99 and up Expy's but the 97 - 98's do have the disconnect. This is why there is a 2H setting on the 97-98's but not on 99-up.

I would check that the front disconnect motor is working. It is possible that the transfer case is releasing but the front axle disconnect is screwing up.

Ian

 

Ian is right. Sorry about the misinformation, wrong year. Do indeed check the actuator motor on the front axle. If it is not disengaging properly then it will cause the grinding noise.

Regards

Jean Marc Chartier

 

Thanks, guys

If it is the actuator motor not disconnecting, would it mean the axle is always locked? I'm not really sure what to check for and I'm a little concerned because I had a very small leak on the passenger side axle which was fixed by Ford. I'm thinking maybe they forgot to reconnect something? (If there is a connection to this motor there?)

Thanks again, guys.

 

It is a vacuum motor attached to the top of the front diff. I can't remember whether the presence of vacuum connects it or disconnects it though.

There is a test procedure in the Haynes manual.

Ian

 

Ok,
I will check it out in the manual.

Thanks!