Shift on the fly or not?
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Shift on the fly or not?
Hey guys, I have a question for you 4X4 types. My truck has the manual 4X4 shifter on the floor. I like to put it in 4X4 hi once in a while to sort of stir the oil. Yesterday when I was going down the road about 40 mph I reached down and pulled it up and wow what a grinding noise. I stopped and it went into 4X4 no problem. Was it because I didn't have the hubs locked in?
Don't want to do that again.
Thanks
Frank
Don't want to do that again.
Thanks
Frank
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Joined: Jul 2003
Posts: 2,454
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From: Adams TN
Yup. once the hubs are locked it's shift on the fly.
if they are unlocked. When the tailshaft is spinning at 40mph. the yoke for the front drive is sitting still. So when at 40mph you kick it in 4hi Nothing is in sync so it has to move that mass of the front driveline to 40mph intantly. It won't do it so you get grinding.
With the Hubs locked. The front driveline is spinning at the same as the rear drive line so when you kick it in to 4hi every thing is already spinning at the same speed all that changes it the power is added to power the front drive shaft but the shaft is already turning because the front wheels are turning the axle with the hubs locked.
I didn't think you were supposed to ben in 4X4 at 40.
Hope this helps
DT
if they are unlocked. When the tailshaft is spinning at 40mph. the yoke for the front drive is sitting still. So when at 40mph you kick it in 4hi Nothing is in sync so it has to move that mass of the front driveline to 40mph intantly. It won't do it so you get grinding.
With the Hubs locked. The front driveline is spinning at the same as the rear drive line so when you kick it in to 4hi every thing is already spinning at the same speed all that changes it the power is added to power the front drive shaft but the shaft is already turning because the front wheels are turning the axle with the hubs locked.
I didn't think you were supposed to ben in 4X4 at 40.
Hope this helps
DT
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Joined: Oct 2003
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Originally Posted by DT 466Man
Yup. once the hubs are locked it's shift on the fly.
if they are unlocked. When the tailshaft is spinning at 40mph. the yoke for the front drive is sitting still. So when at 40mph you kick it in 4hi Nothing is in sync so it has to move that mass of the front driveline to 40mph intantly. It won't do it so you get grinding.
With the Hubs locked. The front driveline is spinning at the same as the rear drive line so when you kick it in to 4hi every thing is already spinning at the same speed all that changes it the power is added to power the front drive shaft but the shaft is already turning because the front wheels are turning the axle with the hubs locked.
I didn't think you were supposed to ben in 4X4 at 40.
Hope this helps
DT
if they are unlocked. When the tailshaft is spinning at 40mph. the yoke for the front drive is sitting still. So when at 40mph you kick it in 4hi Nothing is in sync so it has to move that mass of the front driveline to 40mph intantly. It won't do it so you get grinding.
With the Hubs locked. The front driveline is spinning at the same as the rear drive line so when you kick it in to 4hi every thing is already spinning at the same speed all that changes it the power is added to power the front drive shaft but the shaft is already turning because the front wheels are turning the axle with the hubs locked.
I didn't think you were supposed to ben in 4X4 at 40.
Hope this helps
DT
Thanks, I figured that was it. As per the manual you can put it in 4X4 up to 55, though I can't see the reason. If you need 4X4 the conditions would probably not be right for that speed.
Thanks for the clarification, Ford coud do a better job in the manual on this one.
Frank
