Do you lock your differential in while driving in snow with chains on?

I'd never buy a truck without full lockers. Not after spending an hour shoveling to get my truck out of 4" of snow after being parked all winter. Interaxle lock was useless.

 

First, some definitions:

• Main Differential: Divides the power equally between the two wheel ends of an axle.
• Driver-Controlled Differential Lock (DCDL): Locks the Main Differential in an axle so both wheel ends have equal power.
• Inter-Axle Differential (IAD): Divides the power equally between two axles in tandem configuration.
• Power Divider: Another name for an IAD.
• Inter-Axle Differential Lock (IADL): Locks the IAD so both axles have equal power.

If you don't chain up all four wheel ends, you will need to use the IADL or the unchained wheel ends will not have sufficient traction and you may spin out at a critical point.

In terms of usage, after decades of experience of getting trucks and loads into places they have no right to go, in conditions most drivers will never come close to, let alone see, on time, intact and without breaking the equipment, and consistent with manufacturers manuals:

IADL: engage at any speed so long as both axles are rolling and spinout has not started to occur (throttle on or throttle off), any road surface, may be used at all speeds and for long time periods (I've left mine locked in for months in winter).

DCDL: at or below the engagement speed (on newer trucks the engagement/disengagement speeds are controlled by the ECM, i.e., 25 km/h/45 km/h... on my trucks I had the engagement speed and sometimes the disengagement speed increased), so long as you're not spinning or turning, should be very loose/slippery road surface/poor traction conditions (i.e., "off road"). A truck with either DCDL engaged will "push" and not want to turn. Having both engaged makes it worse. In very low traction conditions and at lower speeds you will need to disengage one or both of the DCDLs in order to make turns.

Drivers may use both the IADL and the DCDL for maximum traction under icy, snowy or poor road conditions.

- Customer Support - North America​

tl;dr I would use the IADL (and possibly the DCDL) before chaining, but I would for sure use at least the IADL if chained, and especially so if only chaining one axle (I've pulled fully loaded B-trains (140,000 lbs) through very slippery conditions with just one axle chained, but using both the IADL and DCDL).

 

About the only time you might consider it is if for some reason you have to stop and resume on an incline. Anything you can do to reduce or eliminate slippage with chains on is a worthwhile effort. But normal operation uphill? No. Not as a general rule unless you start noticing mild slippage in deeper snow where you may not be able to find pavement.

 

Manufacturer's literature explaining how the components work and why you should use the Inter-Axle Differential Lock (and possibly the Driver-Controlled Differential Lock) when chained up (especially if only chaining one axle).

http://graphicvillage.org/meritor/TP9238.pdf​

 

All these acronyms reminds me of ATC in the newer trucks. Automatic Traction Control.
It will derate the motor and reduce power to keep the wheels from spinning. BAD news trying to go though mud. It will stall out right in the middle and leave you looking like a dummy if you forget to disable it first. Don't ask me how I know, I don't want to talk about it.

 

I don't have to ask; been there, done that... mentioned in several posts.

 

What texan said.

I"m picky about traction and possibly slipping out.

I've been running the rockies for 20 years. And I always use chains and dividers and locks.

 

ATC can be disabled on every truck I’ve driven lately so I fail to see where this should be an issue, if it ever becomes an issue.

 

It becomes an issue when you forget it's there. Maybe you pull into a place to deliver and get distracted by all the trucks waiting in line. Someone at the receiver/consignee/security needs a whoopin and you are busy thinking about that instead of that little ATC button on the far side of the dash. All you want to do it get the job done and not worry about pulling some electronic head out of your butt first.