How to check a shift motor?

[sapogmxr]

Just as the title says. How do you check a shift motor? I have a 4405. I've searched but could only find how to rebuild one. Please help.

 

[DeRocha]

There is a section within the explorer maint page (in my sig) that deals with the shift motor and checking it for continuity. What kind of problem are you having?

 

[IZwack]

is this related to ur other thread:

http://www.explorerforum.com/forums/showthread.php?t=142206

one dirty but sure way to check is to leave the dash switch to Auto .. then remove the shift motor and check where the shift rod's arrow is pointing (it should be pointing at 4-HI).. then put the motor back temporarilly and rotate the switch to 4-LO, and then remove the motor and see if the shift rod is now on the 4-Lo position.

 

[sapogmxr]

is this related to ur other thread:

http://www.explorerforum.com/forums/showthread.php?t=142206

Yes it is. But it's a totally different question. Im pretty sure it's the transfer case that has gone bad. The part where the shift motor connects to, is that suppost to spin non stop or is it suppost to stop at some point??

 

[IZwack]

it should stop at two extremes - 4Hi and 4Lo

btw im assuming that ur talking about the shift rod that has the triangular end? (see insert of image above)

 

[IZwack]

spin non stop

that right there is interesting.. so you can spin the shift rod 360 degrees huh? hmmm.. this brings up an interesting idea.

below is what the shift rod looks like if you were to open your transfer case. there are two in the picture, one has a broken pin and one doesnt. dont bother looking at the one that has the broken pin - pay attention to the one at the bottom.

soo as you can see, this shift rod has a few more things attached to it.. the two darker gray items (almost black) on the left side are torsional springs.. and of course theres the obvious helical ramp thats directly to the right of the torsional springs in the image above.

well how ur transfer case works is that there is "cam bearing" that sits in the grove of this helical ramp.. as the shift motor turns, the entire assembly pictured above rotates meanign that the ramp also rotates so that this cam bearing i descibed earlier that sat in the helical ramp is forced to move up and down (or left and right in the picture since the assembly is laying sideways). well it just so happens that this cam bearing that sat in the helical ramp is part of the shift-fork assembly... so that when the helical ramp turns, the shift fork is moved up and down (or again, in the picture above, it would move left and right since the helical assembly is laying sideways). so here's what the entire thing looks like:

​

in the last image above, ive higlighted two of the three shift points on the helical ramp - that is 4Hi and Neutral. note that the helical ramp can not rotate past 4Hi and 4Lo (though you cant see it in the image because 4-Lo would be on the opposite side) because the ramp only goes so far (see the first image)

now going back to what you said - the shift rod is able to spin all the way around - this brings up an interesting idea.. in the last image above, lets imagine that the closest arm of the fork to us was broken off.. this would allow the entire for assembly (including the cam bearing that was sitting in the helical ramp) to rotate... more specifically, lets imagine that the fork assembly is rotated counter-clockwise so that the only arm left is moved away from the viewer.. this would mean that the cam bearing would no longer be sitting inside the helical ramp - which would mean that the helical ramp and the entire shift rod assembly is able to rotate freely 360 degrees..

just a thought.

EDIT: come to think of it, the "cam bearing" i mentioned isnt really a "bearing" , it doesnt actually have a ball bearing or anyting... but hopefully you can still understand the main ideas and concepts i was trying to point out.

EDIT part 2: disregard the previous EDIT as there really is a bearing .. though its not a ball bearing but rather just a sleeve/bushing (checked today).

 

[sapogmxr]

WOW Im VERY impressed! Thank You for your time. I will let you know what the outcome is.

 

[IZwack]

sapogmxr >> any updates on ur transfer case?

 

[sapogmxr]

I've gotta ship it back. Im in the process of doing that still.

 

[IZwack]

ahhh ok.. thought it was a local transfer case shindig.