Passenger side IFS issue.

[Cary Nickel]

My wife and I purchased a 2014 GMC Sierra 4x4 Extra Cab last May, primarily because we needed a better tow vehicle for our 25 foot travel trailer, and wanted some off pavement capability.  As a truck, it's great.  As a 4x4, it is, frankly, terrible.

We've found the truck, unfortunately, has no off road capability at all.  It repeatedly destroys the front passenger side axle in a couple of ways.  The first time it broke the CV shaft, which I chalked up to a fluke, thinking it was just time for the half shaft to give up the ghost.  However, this didn't appear to solve anything, as rather than breaking the new CV shaft, it has since instead pulled the axle shaft out of the axle housing.  It yanks the snap ring through the inner thrust washer, which seems to also operate as a retaining washer, destroying the the seal and rendering the 4x4 inoperable as the sliding inner spline connector no longer can connect the shafts together.  I get a dreaded "4 wheel drive is off" message, and then proceed to get stuck.  We initially thought this was all due to a leveling kit which was installed on the truck by the previous owner causing extreme angles in the IFS, but the leveling kit has been removed and the truck is back to stock height.  A few days ago, it pulled the axle shaft out a second time and got us stuck in sand along the Mojave Road in California.  Kudos to OnStar for sending a 4x4 recovery team to pull us out of the sand ten miles from the nearest pavement, but the 4x4 is currently broken for the third time.  We don't do any hard wheeling with the truck, but it can't seem to handle any wheeling at all.  I've searched the internet for similar situations to no avail, and frankly, I'm stumped.  It's always the passenger side front that is affected.  In comparison to 4x4's I've owned in the past (admittedly mostly straight axle models except for a Jeep Liberty, which was a garbage vehicle overall but had 4x4 that never failed, even during some tough wheeling), it appears the 2014 GM 4x4 IFS is a rather weak design, but I'm sure GM engineers are smart enough to design something that wouldn't continually break like this just from turning the 4x4 on.

Any ideas?  The truck suits our purposes in every other way, so I'd rather solve the problem and keep the truck than get rid of the truck and simply pass the problem on to someone else.

Edited April 30, 2022 by Cary Nickel
Clarification/misspelling

[CamGTP]

That problem would annoy me enough to just buy a used front diff and slap it in there to see if that cures the problem.

[Cary Nickel]

But what do I do when the axle shaft gets yanked out of the replacement dif? 

[richard wysong]

it sounds like you may have the wrong replacement shaft, it's probably a bit too short for the suspension travel