2016 4x4 will grind and clunk/ not engage

HDdave

Member
Nov 16, 2010
171
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16
Wilmington, NC
Been quite a while guys- have a 2016 denali hd now. I honestly have had questions about its 4x4 since it was new. Never really bothered to test it when i bought it off the lot at Laura.

Noticed the truck never really felt planted off road- i just assumed it was me getting used to sand instead of mud. Nor did it ever chirp the tired or anything at full lock. But then i got it stuck good one day with 35k or so on it. Saw the front tires doing nothing. Took it in, they said it was the actuator in the front diff. They replaced it and on my way. Still never felt weird at full lock in 4x4. Got stuck again at like 50k miles , went thru the same process.

Recently got buried (Was around 90k). Took it in, they looked at it for an hour- claimed they checked the front actuator it was fine, and that they changed transfer case fluid and found metal on the drain plug and that i needed to open I’m the transfer case. I hate this dealer anyways so just left think f i will do it myself.

So i find myself here hoping to diagnose before i spend $2k on a transfer case to swap out and it still doesn’t work.

Sitting still you can’t tell much of anything is happening when you turn the knob. When rolling and you turn it, you can hear/ feel a grind for a second and a half or so, then a nice solid clunk (kinda how some of my older Dmax trucks felt going into 4). But then no 4x4 still… just as my employees have started to call it- a $75k Prius with mud tires.

Appreciate it
Dave
 

2004LB7

Well-known member
Dec 15, 2010
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does it work in 4low? maybe shift fork is worn. I'd drain the fluid and pop the cover off and inspect everything. not too difficult to do
 

HDdave

Member
Nov 16, 2010
171
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Wilmington, NC
Will do on the codes, I will get them this week if there is anything. To the best of my knowledge there aren’t any codes, but I could be very wrong. It’s been quite a few years since I have done much duramax related.

It does not work in 4 low. It was suggested to me to pull out the front actuator and check it so I can see it visibly moving myself. It will have to wait till the weekend as all 3 of my warehouses are full of cabinets and the truck wont fit in the garage at the house.

Hopefully I can track this issue down with some help on here and some research of my own. After multiple attempts at the dealer I would rather not take it to anyone anymore. I was able to get a SMG transmission out of a bmw M3 and convert it to a 6 speed (and it actually works lol). So I have got to be able to get this problem knocked out.
 

2004LB7

Well-known member
Dec 15, 2010
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Norcal
the code would be in the 4x4 module so many cheaper readers wont read it.

jack the front end up off the ground and see if you can turn the front drive shaft when it is in 4wd. this should tell you if its the front or rear actuator
 

HDdave

Member
Nov 16, 2010
171
0
16
Wilmington, NC
Yeah I appreciate that haha. We will pull the codes this weekend, and I will do some investigating on what i can and cant spin. I will pull the actuator out and test that too.. Should be a good starting point.