2012 Chevrolet Silverado 1500 won't engage in 4WD

I have had the differential changed, but the truck still does not engage into four wheel drive. The electronic shift on the dash used to shine blue on the outside of the ring [yellow on the setting on the inside of the ring–2 WD, Auto, 4 Hi, 4 Lo] when engaged, but even now after the differential switch out, it is amber instead of blue, and it will not remain in 4 X 4 .

Which differential was changed and why? If it was the front one, maybe the wiring to the hub actuators was damaged or not properly re-connected.

Does the dash say “service 4WD”? That can appear when the switch goes bad - a frequent issue and cheap to repair - Or it can appear when the 4WD actuator (or just the sensor) on the transfer case has gone bad, Or the hub-actuators have failed.

Take it to your local independent auto shop and let them have a look or take it back to whomever replaced the diff.

No message on the dash indicating to service the 4WD…there is a dash symbol that indicates that you are driving in 4WD when it is set in 4H (or 4Lbut I never use 4L), but it too disappears when the normally blue light on the outer ring of the electronic shift dial turns amber (or doesn’t illuminate at all), indicating that the vehicle is in 2WD (and confirmed when I couldn’t drive up my driveway this weekend).



One question answered but the rest not, same answers…

Why the diff change? Which diff?

Probably the switch, have it checked.

Having problems reconnecting with you with attachments, so I have replied twice earlier after separating the two attachments from being together to the two individual attachments.

Tried to copy/paste my earlier responses, but to no avail…so here it goes again…

The front dif was changed out along with other parts as indicated on the two paid invoices. In between the two jobs, the mechanic attempted one other ‘fix’ that did not work, so only charged me $300 for the rebuilt part, not the labour–no paperwork to indicate what that piece was.

The problem…I can set the electronic shift to 4H, the two lights will indicate: inner light (orange colour) indicates where I have set the wheels (2WD, Auto, 4H, 4L)…this light changes no problem. The outer light on the dial, when working properly, changes to blue once the selection and shift is done. Instead of blue, it changed to an amber/yellow colour…and this is when I also discovered that even though the inner light indicated the setting was for 4H, that in fact I was only driving in 2WD. We had the initial repair --CV Axle Invoice–done. It appeared to be working when tested, but the blue light did not return–there was no light on the outer dial… Took it back in, replaced the diff the first time, amber/yellow colour light returned, then no outer dial light. Took it back in a third time, had the front differential changed again (thought faulty rebuild on first attempt), appeared to be working…less than an hour later, returned to 2WD, inner light still indicating set on Auto or 4H, but only operating in 2WD.

Thanks for you time & effort


Your issue is more likely either the switch or the transfer case.

David, I can’t see any invoices nor would that help a whole lot. You never said WHY the front diff was replaced, just that it was, twice. If it was replaced because it wouldn’t go into 4WD, stop taking it to the shop that did the diff work because they have NO clue what they are doing.

You also mention CV axle work, was one or both replaced? Why? Same comment, if the shop thought that was the problem, no clue, find another shop.

The switch is telling you the transfer case isn’t sending drive to the front diff not that the front diff is bad.

For the 3rd time, switches are cheap and easy to replace. Start there but get the error codes read from the transfer case controls.