ventilation and auto hub problems

[04dave]

I have an 04 6.0 ... The ventilation is stuck on defrost and my auto locking hubs do not engage on the fly. On the passenger fender is a vacuum pump (part no. 6c32-2a451-a) that used to make a noise and now doesn't ... does anyone know if this controls thes two items?

[SDDan]

Had the same problem with the defrost stock on, I didn't check to see if the auto hubs were effected at that time. The dealer replaced the vacum pump. Now I have had times when placing the truck in 4wd lo, the ventilation would switch to defrost. The dealer said it was probably a vacum leak. Unfortunetly it is an occasional problem and the last time the truck was in the dealer they could not get it to malfunction. Based on this I believe they work from the same vacum source. Hopes this helped. Dan

[benderado]

IMO just ditch the auto locking hubs. Get a nice set of Warn manual locking hubs. Good luck with gettin' all this figured out!!!

[Raul@Stealth Automotive]

+1 more for Warn Manual hubs... i was stranded not being able to engage 4x4 because of a leak... now i upgraded to the warn hubs and they are great.. never worry anymore

[lightninmike]

Weird this came up. The other day we ended up with 11 inches of snow and i got stuck at a redlight. Me the *** with the F250 PSD spinning at a light. So I put my foot on the brake and put it in 4x4. To my surprise i still sat there not moving. So i checked the transfer case and that was locked up but the hubs didnt.
Pulled the lines off the knuckles and checked them for suction. The pump came on fine but it seemed that the drivers side wasnt locking up. After messin with it for about a 1/2 hour i was satisfied that i had good suction and i reconnected the hubs and now they work fine........... I didnt do anything special but i think i will be replacing lines when the weather clears up a bit

[dirtbikeguy2003]

Cant you manualy lock the hubs in when the pump wont activate them?

[lightninmike]

Yes but getting out at a redlight or green in my case may get you run over

[Evil Eye]

It's a known problem and yes, they are connected since they both require vacuum from the same source...