Timjame0719 Posted January 27, 2014 Share Posted January 27, 2014 Hello all, new here and fairly new to the Super Duty. Although I had a 2000 F250 a long time ago, the 4x4 system never properly worked but now that I'm back to the super duty I have a few questions on the operating system of the 4x4. I bought a pretty used 2007 F-250 super duty CCSB with the 6.0 PSD. I know all about the 6.0 weaknesses and they have been addressed but when I got it I noticed the 4x4 wouldn't engage with the switch in the cab. I have auto hubs no manual stick inside. I knew from my last one that the seals in the hubs were probably bad. So I had the Ford dealer I bought it from replace the seals. The 4x4 engages immediately from a stop or on the fly no problem now with hubs in auto position and cab dial on 4x4. But, here's what happened yesterday and maybe somebody could help me understand why this happened..... I have a long driveway with a hill and we had 6+ inches of snow in it unplowed. I had family following me up the driveway in a new Ford Explorer front wheel drive. They got stuck at the bottom but I was in 4x4 with my hubs in auto position and cab dial to 4x4. The 4x4 was engaged just like it should be and pulling me right up the driveway. I noticed they were stuck so I turned around (still engaged in 4x4) in my yard to come back down and help. I didn't see the snow covered rock that was in the yard and as luck would have it I drove up on it and beached the front right portion of the axle on the rock. My front right tire was off the ground and my right rear tire was barely touching the ground. I tried to back off it but the only wheels that were spinning were my front right one that was off the ground and right rear one that was barely touching the ground obviously not enough traction to pull me off. I thought if I locked out the hubs I could get the front left that was well on the ground to spin. No dice. Seemed to me locking out the hubs never changed a thing and I could never get any other wheels to get power. Even tried 4x4 low. Nothing. I had my neighbor pull me off with his JD tractor. My question is why did the left front and rear tires never get power? I was in 4x4 mode when I hit the rock so they were all engaged when I hit it so it wasn't like it didn't have a chance to lock in. My neighbors chevy did the same thing in the ditch where one wheel was off and same side barely on and all his wheels spun at the same time enough to get him out. Any explanation would be helpful! Thanks in advance! Quote Link to comment Share on other sites More sharing options...
akirby Posted January 27, 2014 Share Posted January 27, 2014 4x4 only sends power to the front and rear axles. The front and rear differentials determine if you can send power to the other wheel when one wheel is off the ground. It looks like Traction-Lok axles were optional on the 2007 F250 and from what you described you don't have them - or if you do they aren't working. This means you really only have 2 wheel drive - one front and one rear. You can replace one or both differentials with a limited slip version. Quote Link to comment Share on other sites More sharing options...
Timjame0719 Posted January 27, 2014 Author Share Posted January 27, 2014 That makes sense. Frustrating to say the least but it was my fault to begin with I guess. I will certainly be looking at upgrading that system then. What's the difference between using the dial with hubs in auto or locking the hubs out? I noticed no difference. Quote Link to comment Share on other sites More sharing options...
fordmantpw Posted January 27, 2014 Share Posted January 27, 2014 akirby is correct. It's quite possible you DO have the limited slip rear, as those were basically junk in the Super Duty trucks. They just aren't strong enough for the torque of the diesel. My LS rear is basically useless. If you want true traction in the rear, go with a locker, not a limited slip. As far as auto vs. manual hubs, the only purpose of the auto hubs is as an override in the event that the auto-hubs fail. As long as the auto hubs are working fine, there is no difference between auto and manual. Quote Link to comment Share on other sites More sharing options...
Timjame0719 Posted January 28, 2014 Author Share Posted January 28, 2014 Now that makes sense to me. Manually turn the hubs when the auto seals are bad. The dealer told me use the dial when roads are snowy but the hub locks are for when you are "really stuck". That made no sense at all to me. Thanks everybody! Quote Link to comment Share on other sites More sharing options...
fordmantpw Posted January 28, 2014 Share Posted January 28, 2014 Now that makes sense to me. Manually turn the hubs when the auto seals are bad. The dealer told me use the dial when roads are snowy but the hub locks are for when you are "really stuck". That made no sense at all to me. Thanks everybody! You can also lock the hubs if you are constantly switching between 2x4 and 4x4 to save wear on the locking mechanism. Snowy roads where you go from clear to patchy areas would be a good instance of this, but no, you don't need to manually lock the hubs when you are 'really stuck'. Quote Link to comment Share on other sites More sharing options...
Timjame0719 Posted January 28, 2014 Author Share Posted January 28, 2014 Gotcha thanks. Does it matter if I'm on the freeway and the hubs are locked manually but dial is 4x2? Quote Link to comment Share on other sites More sharing options...
fordmantpw Posted January 28, 2014 Share Posted January 28, 2014 (edited) Gotcha thanks. Does it matter if I'm on the freeway and the hubs are locked manually but dial is 4x2? The front axle will still spin, but the transfer case will be unlocked. It will decrease your fuel economy slightly, but not really enough to make much difference in something as large and inefficient as a Super Duty. Edited January 28, 2014 by fordmantpw Quote Link to comment Share on other sites More sharing options...
YT90SC Posted January 28, 2014 Share Posted January 28, 2014 akirby and fordman, I am unsure that the O.P. knows how to properly fully utilize his Limited Slip/Traction Lock. Limited Slip or Traction Lock uses two clutch packs, one sandwiched between the side gear (attached to the axle) and diff housing. These packs are set to a minimum break away torque through use of a Bellville spring on each side or "S" spring between the side gears. This torque ranges between 25 lb-ft (bare minimum) and 100 lb-ft or so. It is that low so that you can turn corners without wheel hop or chatter. This system is ingenious because the more torque you successfully apply to the system, the more it will hold (yes even a diesel). If you are one wheel peel-ing, stop, apply the service brakes lightly or the park brakes lightly and then slowly add engine power. This will cause the torque across the diff to increase. This torque load causes more outward load on the side gears which makes the clutches apply harder. You can channel CRAZY amounts of torque through them if you get the brakes and throttle right. Lose that torque across the system by mashing the throttle or not enough brake and you are back to that minimum break away torque. Practice this and you can get both wheels to grab just as well as an expensive locker. Just takes a little practice. Quote Link to comment Share on other sites More sharing options...
fordmantpw Posted January 28, 2014 Share Posted January 28, 2014 akirby and fordman, I am unsure that the O.P. knows how to properly fully utilize his Limited Slip/Traction Lock. Limited Slip or Traction Lock uses two clutch packs, one sandwiched between the side gear (attached to the axle) and diff housing. These packs are set to a minimum break away torque through use of a Bellville spring on each side or "S" spring between the side gears. This torque ranges between 25 lb-ft (bare minimum) and 100 lb-ft or so. It is that low so that you can turn corners without wheel hop or chatter. This system is ingenious because the more torque you successfully apply to the system, the more it will hold (yes even a diesel). If you are one wheel peel-ing, stop, apply the service brakes lightly or the park brakes lightly and then slowly add engine power. This will cause the torque across the diff to increase. This torque load causes more outward load on the side gears which makes the clutches apply harder. You can channel CRAZY amounts of torque through them if you get the brakes and throttle right. Lose that torque across the system by mashing the throttle or not enough brake and you are back to that minimum break away torque. Practice this and you can get both wheels to grab just as well as an expensive locker. Just takes a little practice. Hmmm, interesting. I need to try that with my Super Duty. I never needed to do that with my F150's, so never thought of trying it with my F250. Next time I get in a (un)sticky situation, I'll give that a shot. Thanks for the tips! Quote Link to comment Share on other sites More sharing options...
Timjame0719 Posted January 28, 2014 Author Share Posted January 28, 2014 Great information from everybody! Thanks very much for your time here. Hopefully there won't be another time like this on that rock as I am removing it in the spring but with my luck soon I will see if I can master that technique! Quote Link to comment Share on other sites More sharing options...
billyjg2007 Posted February 10, 2014 Share Posted February 10, 2014 So, even with an E-lock rear, I will only have power to 3 wheels? or does the front lock too? Quote Link to comment Share on other sites More sharing options...
fordmantpw Posted February 10, 2014 Share Posted February 10, 2014 (edited) Rear only. There is no locker in the front, so you would effectively be 3 wheel drive. Edited February 10, 2014 by fordmantpw Quote Link to comment Share on other sites More sharing options...
billyjg2007 Posted February 10, 2014 Share Posted February 10, 2014 That's something else!! What about an "all-wheel" drive? Quote Link to comment Share on other sites More sharing options...
akirby Posted February 10, 2014 Share Posted February 10, 2014 That's something else!! What about an "all-wheel" drive? AWD like you see in most cars and CUVs are full-time systems that are normally FWD or RWD only until slip is detected or anticipated, then they transfer power to the other axle as needed. Some systems send power to both axles at all times but there is no low range where the front and rear axles are locked together. The front and rear axles work the same way - either they are open differentials, limited slip or electric/pneumatic locker. On some vehicles they use individual wheel braking to simulate a limited slip differential - they brake the spinning wheel sending torque to the opposite wheel. Quote Link to comment Share on other sites More sharing options...
billyjg2007 Posted February 10, 2014 Share Posted February 10, 2014 Very interesting. Thank you for the education! Quote Link to comment Share on other sites More sharing options...
mack7265 Posted July 6, 2015 Share Posted July 6, 2015 I have a question concerning the 4x4 system in my 2012 F250 King Ranch FX4. I have 3.73 gears, and it appears to have locking dif's, I have spun both of the rear tires. My question is, what is the purpose of pulling out the knob to engage the four wheel drive. Does this lock all wheels in? I did it once and it felt like the truck was going to come apart. Quote Link to comment Share on other sites More sharing options...
akirby Posted July 6, 2015 Share Posted July 6, 2015 A locking diff locks the left and right wheels together on one axle. The 4wd knob engages the front and rear axles. Using 4LO and/or locking the diffs on pavement will cause driveline windup. This is all explained in the owner's manual. Quote Link to comment Share on other sites More sharing options...
fordmantpw Posted July 6, 2015 Share Posted July 6, 2015 I have a question concerning the 4x4 system in my 2012 F250 King Ranch FX4. I have 3.73 gears, and it appears to have locking dif's, I have spun both of the rear tires. My question is, what is the purpose of pulling out the knob to engage the four wheel drive. Does this lock all wheels in? I did it once and it felt like the truck was going to come apart. You only have a locking rear diff, not a front diff. Pulling out the 4x4 knob will lock the rear diff. You don't have to pull it out to engage 4x4, only to lock the rear axle. You don't have to have it in 4x4 to lock the rear axle. akirby covered the rest. Quote Link to comment Share on other sites More sharing options...
truckinguy Posted July 6, 2015 Share Posted July 6, 2015 Also with the rear electronic locking axle it will unlock by itself when you hit speeds of 20 or 25 mph then when you slow back down to below that it will re engage. Quote Link to comment Share on other sites More sharing options...
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