2002 f150 shift on the fly

[Haley-Special]

i have a manual shift 4x4 the shift on the fly no longer works. i need to be at a dead stop or else when the vaccum actuator engages there is a grinding.

[shelbyx1]

you could have a shift fork broken in the front diff,is a common concern.

[Haley-Special]

hello,
if that were the case would the 4x4 work at all??

[shelbyx1]

they tend to brake one tab off the fork causing it to only push on one side of the collar,i've also seen the vacc lines behind the battery rot apart causing this same issue.

[Haley-Special]

ya i checked the vaccum lines, i can see the acctuator working when my friend puts it in 4 wheel drive. if there were a electrical prb in the t case would that put the service engine light on?? could a problem with the vaccum lines affect the shift on the fly, although the 4x4 will still work if i do it from a dead stop??

[shelbyx1]

do you have a manuel stick t/case?if you do the only elec conn will be the range sensor,if the front diff lever is moving full throw the fork could be at fault,try moving the diff lever manuelly while turning wheel it should engauge smoothly.

[Haley-Special]

what about the electromagnetic cluch in the transfer case, even the manual ones have it dont they?

[shelbyx1]

yes they do have a electro syncroniser clutch,check fuses 53 in cjb(under dash)and bjb fuse#37,then check for voltage on shift to electro clutch if batt voltage then check resistance of clutch to ground(should be aprox 1000ohms),but if your getting a grinding in diff on engaugement i would be checking that first.

[Haley-Special]

would there be a service engine light on if there were an electrical prb in the T case?? will a scanner help at all??

[shelbyx1]

you won't have a check eng lamp on but there may be t/case codes in the gem module(p1804-1891)that may help to diag.if you need help to interpret codes feel free to pm me.:)

[Haley-Special]

does a manual shift case still use a GEM??

[shelbyx1]

yes for the syncro and front diff lockup,they call it the chime module instead.