fdgdfg

 

Try greasing the splines on the slip yoke.

 

fgd

 

I highly recommend moly lithium grease.

I've used this with good results:

 

my 06 was doing the same thing, shuddering between 1 & 2nd gear. ended up getting the tranny rebuilt, issue went away. mechanic said the valve body was damaged. everything seems to be working ok now, my truck had 74k miles when i took it in.

 

How much did a tranny rebuild cost? Who does that?

 

gdf

 

I'd suggest putting the truck on jack stands or a frame lift and running it thru the gears while looking underneath. Are you sure it's not the front end engaging? The system will engage the 4x4 if the vacuum falls which it will during acceleration.

The Ford recommended grease for the slip yoke is a teflon grease, not a lithium. The shearing at the slip yoke is tremendous and the teflon keeps things moving like it should.

 

fgh

 

The problem is your front bumper, you need to remove it and let me have it.

Have you tried manually shifting 1-2-d-o/d to see if the symptoms remain?

 

hgj

 

Shift it manually with the shift lever. Start with O/D switched off lever in 1, increase RPM to about 2500 and move selector to 2, increase RPM to about 2500 and move selector to D, increase RPM to about 2500 and turn O/D back on.

Obey traffic laws etc. etc.

It may show the transmission trying to be in two gears at once.

 

gfh

 

Your gear lever has P R N D 2 1 - and you have a button to turn overdrive on and off. When the "overdrive off" light is on, overdrive is off. With the engine running in D and your foot on the brake, push the button to turn the OD light on and pull the lever down to 1. Accelerate, when you reach 2500 rpm move the lever to 2. When it reaches 2500 rpm again, move the lever to D. When it reaches 2500 rpm again, push the button to turn the OD light off. Note that 2500 rpm in D with OD off could be be around 70 mph.

 

dsfghf