2017 silverado 4wd cant seem to be fixed

ABT15-1500 · November 14, 2019

whats good guys? so last weekend my 4wd in my 2017 1500 silverado got busted. Guys in the showroom said it overheated and stuff got busted in the transfer case. replaced the whole transfer case + actuator. Just got a phone call saying that 4wd button is not working and not switching from 2wd 4 hi and 4 lo. When it stopped working was stuck in nasty mud and really pushed the truck trying to get out, one of my buddies noticed that only the rear tires were moving and the truck was set to 4hi. tried turning the knob and nothing changed stayed on 4hi and got a service 4wd message that. Now with the new transfer case and actuator guy at the dealership say still the issue is present car is not switching and the light is stuck on 4wd. note: not from the states and the guys at the dealership seem to know less than i do about cars. Can you guys point me in the right direction on what i should advise them to check? or what might be the issue ? where they should look? etc

Thank you !

davester · November 14, 2019

1. Walk past the guys in the showroom, to the guys in the shop, when discussing what's wrong with your vehicle. The only thing showroom guys are good for is selling stuff.

2. Haul the truck to another dealership. They seem to have hired people even dumber than showroom guys to work in their shop.

It sounds like you've got the basic 2hi/4hi/4lo/neutral transfer case, which has basically worked the same for at least 15 years. If they are depending on the customer to tell them what to do, you need to march into the GM's office and go "WTF dude."

Edited November 14, 2019 by davester

ABT15-1500 · November 14, 2019

I'm from the middle east we only have one dealership sadly. I've paid for a new transfer case and actuator! Almost 3000$ and they didn't fix the issue. Will contact gm head office for out region which in another country also sadly! Thanks for the advice tho.

davester · November 14, 2019

ok, if you have to use these guys, then you/they need to figure out where the problem is.

1. They should have the gm code reader, which will be able to find the code causing the "service 4wd system" message.

2. Use the knob to switch into 4hi while moving slowing (moving is just so the gears can engage). Stop, put in park, lift one front wheel.

If wheel doesn't spin. Success, it's in 4wd.

If wheel spins, then reach under the truck and try to spin the front driveshaft (goes from the transfer case to the front differential).

If the driveshaft doesn't spin, it means the transfer case is in 4wd mode, but the front axle is either not locked or busted inside (so, it could be anything from the 4wd sensor in the transfer case, to a wiring problem, to the actuator in the front diff, to stuff busted in the diff).

If the driveshaft does spin, it means the transfer case isn't in 4wd mode, or the transfer case is broken (unlikely as it's new, but still possible). More likely it's a wiring problem or an encoder problem (the motor that controls what mode the transfer case is in), or possibly a problem with the switch.

davester · November 14, 2019

Alternately, given that they are a dealership, they should have the full-service manual for your truck, and it has the exact steps to go though to find out what the problem is and how to fix it.

ABT15-1500 · November 14, 2019

davester, really appreciate your help !

Sent an email to GM, Also told them to stop working on my truck and will try following the instructions you provided. The dude is saying theirs a wiring problem now, im starting to think that the transfer case was fine this whole time and i was charged for a whole lott of new parts which didn't need to be replaced. Also told them to keep all the old parts they removed will go to another shop that works with all trucks so he can confirm if the parts they removed are really damaged. its pretty annoying what these guys do ! they just sweet talk me and give me promises they cant keep up to.

1SLOW1500 · November 14, 2019

Sounds electrical the whole time. I would manually over ride the switch. They use a scanner tool. With the truck in the air see what works and doesn't. I have also seen them remove the drive shafts and test it. This should not be a issue at all.

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