Budman1962

I have a 09 f150 with 160,000 on it. For the last couple months I was hearing an occasional buzzing sound from the engine compartment. Couldn't duplicate it while not driving. The buzzing sound has changed somewhat but it's follow by a grinding sound that seems like the hubs are trying to lock while in 2 wheel drive. I think the buzzing is coming from either the IWE solenoid or the vacuum check valve. My question is this. If I pull the vacuum line off the the solenoid and plug the line will the hubs remain locked till I can dig into this a little deeper. I was thinking that they would stay locked. I should still be able to shift in and out of 4 wheel drive correct? Any help on this would be great.
Thanks

PerryB

Yes, your temporary repair theory is correct, and the IWE solenoid usually IS the culprit.

justjimmy

Agree with PerryB

Tothemax

IWE

Budman1962

I looked at pictures of it online and I thought I knew where to find this solenoid. The pics show On the firewall behind the battery. Another pic showed it next to the brake booster. Can't find it. Where is it on an 09?

Tothemax

I thought it was on the firewall on the passenger side.

Budman1962

That must be on the 04-08 models

Budman1962

replaced the solenoid and it didn't help. I unplugged the vacuum lines to the hubs and the grinding stopped. Its been at the dealer for 2 days now and they cant figure it out. It holds good vacuum while in the shop and the hubs stay disengaged. While driving they try to lock.

PerryB

Based on that, I would have to think you have a supply-side problem, between the IWE sol. and the vacuum source.

Budman1962

Turned out to be the check valve. Pulled it off and I could suck air thru it both directions. Replaced it and everything is fine.