Heavy Duty Mechanic Explains the difference between 4WD LOCK and 4WD HIGH in RAM 1500 and RAM 2500 trucks. Putting it simply 4wd lock and 4wd high mean basically the same thing. 4wd lock means the transfer case is locked and in ram's case the transfer case is also in 4wd high.



I hope everyone is having a great weekend! I wanted to touch on this topic because I saw a couple questions online about the difference between 4wd lock and 4wd high. I know with ram trucks alot of the time their 4wd options are 4wd auto, 4wd lock and 4wd low. where as other trucks have 4wd high and 4wd low. now like I mentioned in ram's case 4wd lock is also 4wd high in a perfect world they would say 4wd lock high or 4wd lock low.

I think ram uses this 4wd terminology because many trucks take advantage of having a clutch pack transfer case (bw44-44) which can utilize 4wd auto and truck can in theory be in 4wd but not having a fully locked transfer case. therefore letting the driver know with 4wd lock that the truck is always in 4wd.

but I think for people who are new to ram or just not sure 4wd lock may imply that all 4 wheels lock up or there is a locking diff. but the truth is 4wd lock only effects the transfer case.

4wd high is simply the selected range. so in rams case 4wd lock is the transfer case fully locked in high range.

now most transfer cases do not have a clutch pack system and the ability to be semi-locked. so it is simply assumed that the transfer case is locked when you select a 4wd range. therefore they use the terms 4wd high and 4wd low. for perfect terminology is should be stated at 4wd lock high or 4wd lock low.

so long story long 4wd lock is 4wd high and 4wd high is 4wd lock. they are essential one of the same thing.

hope that makes sense!