2000 chevy s10 4wd pick up. my truck does not engage the front drive. took to mechanic thinking it was in the transfer case. he said it was probable the cable and/or the solinoid which he said is under the battery tray. he also said probably could do this my self and save some money. while looking online i found actuators are thes the same things? not being able to see this thing under the battery tray im not sure what it looks like yet. any help would be appreciated