4WD engagement question
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Mountain Pass
Joined: Aug 2007
Posts: 101
Likes: 7
From: Charlevoix, MI
4WD engagement question
I was just wondering how everything engages on my '07 FX4 with ESOF when shifting into 4W high while driving along in two wheel drive. If the front drive shaft is not turning and the rear is, how does the transfer case engage without making nasty noises? I guess that's assuming the transfer case engages before the hubs. If the hubs engaged first, the transfer case engagement wouldn't be an issue, but then how can the hubs engage without grinding if the front axle shafts are not spinning. I'm simply curious. My '98 Ranger also had ESOF and vacuum operated hubs that worked fine and my new truck is performing great in the winter weather lately.
MMNC (SS)(Ret)
Joined: Mar 2004
Posts: 11,604
Likes: 149
From: SE Georgia
the motor on transfer case and vacuum hubs are actuated essentially at the same time. however, it takes the vacuum a second roughly to break...I usually feel a very slight bump when that happens. it's not really an issue though because the front driveshaft should already be spinning roughly the same speed as the front tires (through mechanical gearing from t-case and transmission)
the t-case has precision machined gears that allows for the front driveshaft to spin up instantly. FYI, the t-case is always rotating. the only part that isn't is the front output shaft and associated gear inside the t-case
help any?
the t-case has precision machined gears that allows for the front driveshaft to spin up instantly. FYI, the t-case is always rotating. the only part that isn't is the front output shaft and associated gear inside the t-case
help any?
Thread Starter
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Mountain Pass
Joined: Aug 2007
Posts: 101
Likes: 7
From: Charlevoix, MI
Yes, thanks Tylus. I kind of suspected that the transfer case was somehow able to bring the front output shaft up to speed. I've never seen the inner workings of one. While my Ranger and this new F-150 work fine, I learned that I need to anticipate needing 4WD and engage it before it's too late. For instance, my daily commute requires me to climb a steep hill right after turning right from a stop sign. If I think it might be slippery, I need to engage 4WD before coming to a stop. It's too late when half way up the hill and 2WD isn't getting the job done. Sometimes I miss good old fashioned manual locking hubs and a transfer case lever on the floor. Thanks again.
Martin
Martin
Elder User
Joined: Dec 2007
Posts: 680
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From: Michigan
They have hills in Charlevoix? Members of our WAM team do 'the WALL'. You can shift into it going up the hill, but I always like to shift before and need it and normally let off the throttle before I flip the swtich to minimize the clunk! No problems to date with almost 90K miles on mine. PS- I like your ham setup. Very nice install of your radio and antenna. I have a buddy down here that is a hammer as well.
Thread Starter
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Mountain Pass
Joined: Aug 2007
Posts: 101
Likes: 7
From: Charlevoix, MI
Originally Posted by Twinsdad98
They have hills in Charlevoix? Members of our WAM team do 'the WALL'. You can shift into it going up the hill, but I always like to shift before and need it and normally let off the throttle before I flip the swtich to minimize the clunk! No problems to date with almost 90K miles on mine. PS- I like your ham setup. Very nice install of your radio and antenna. I have a buddy down here that is a hammer as well.
Martin KC8CFP
