7.3 liter diesel, auto trans
my truck runs normally in reverse, but slo to go in forward gears,OD is flashing on 2002 Ford F-250 Super Duty
get a free diag and est from aamco then post results
The overdrive light flashing means the TCM (transmission control module) has detected a problem and is setting a trouble code(s). Your symptom of being sluggish in forward gears suggests the module has shut down the operation of the shift solenoids and your truck is in failsafe mode, so you are starting out in third gear. You need to pull the codes from the TCM and have the problem diagnosed.