Hi, I've got an 01 f150 with the manual shift lever and for some reason my 4x4 will not go into 4HI on the fly. It will go in if I am doing less than 10 mph. Any Reason for this would be appreciated!

 

Shifting on the fly means that
bot the front and rear are spinning at the same
speed.
If one is slipping bad things will happen

 

Do your front and rear tires have the same amount of tread left on them? If they have different amounts of tread the difference in the diameter of the front and rear tires may not allow the transfer case to engage the front axle at higher speeds.

 

I thought only the electronically controlled one's were shift on the fly?????

 

No, all can be shifted on the fly up to 55mph to 4hi, not 4 lo. Even my 85 would do that as long as the hubs (manual) had been locked in.
That does not mean you should shift if the rears are spinning. That is when you have problems. As long as the front and rear wheels are turning the same speed, you can shift on the fly.

All in the owners manual.

 

Check fuse #23 in the Central Junction Box in the cab. Do you hear the SOTF relay click when you engage 4Hi If the relay is deffective it will not engage the t-case electromagnetic clutch
Check the maxi fuse #103 (30amp) in the battery Junction Box under the hood.
If it popped your t-case electromagnetic clutch will not work and the driveshafts will not sync up.

JMC

 

ok thanks for clarifying for me

 

Thank you, I will check those fuses and let you know!

 

So I checked the fuses and they are all ok... any other suggestions? could maybe be the electromagnet clutch itself?

 

Check the connectors at the t-case for corrosion. Also check the 4x4 relay under the oval cover on the dash.

JMC

 

It sounds like an electronic issue (fuse?). My manual shift t-case will engage at speeds up to about 55-60mph. I rarely, if ever need to engage at that high of a speed, but it has done it when needed. Check the fuses and other electronic connections first, and make sure that you are turning the same speed front and rear (I.e. not spinning the rear tires, or running different gear ratios or tire diameters).

 

All the Borg-Warner 44-06 part time t-cases have an electro magnetic clutch that will sync the front and rear drive lines so the t-case can engage at speed. If it is not engaging at speed the clutch is not engaging and spinning up the drive lines. It could be defective or it is not getting electrical power when it should. There is a relay that is responsible for supplying the current to the clutch. It is grounded by the GEM when 4x4 is requested. The relay is located under the oval cover on top of the dash. I cannot tell you which relay it is as I moved mine around in there. I can tell you that it has 4 wires; Dark Green/Light Green stripe, Brown, White /Light Blue stripe and Orange. When 4x4 is engaged power flows from the fuse through the Dark Green/Light Green striped wire to the Brown one. You should have 12v at the Dark Green/Light Green striped wire all the time. You should have 12 at the White /Light Blue striped wire when in RUN. The brown wire should have continuity to ground if not the clutch is defective or the circuit is open. Check the connector at the t-case for continuity. It is on the t-case extension housing. If the any of the power tests fail check the fuses again.

JMC