WHEN THE TRUCK IS IN DRIVE DOES NOT WANT TO GO FOWARD STICKY ? on 1991 Ford Explorer

WHEN THE TRUCK IS IN DRIVE DOES NOT WANT TO GO FORWARD
WHAT COULD BE THE PROBLEM ?
THE 1991 FORD EXPLORER REVERSE OK.
COULD IT BE A SHIFTING LINKAGE CABLE ?
HYDROLIC PUMP LINE ?
VACUUM MODEGULER?

Asked by for the 1991 Ford Explorer
1 answer
Does the engine rev up when in drive?Does it try to pull?Have you checked the emergency brake?