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4x4 gear swap to the rear only for now

MarcuM

By MarcuM
in Engines & Drivetrain

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MarcuM Enthusiast

MarcuM

Posted
Posted

2016 5.3 6sp cc with 140k and 11” lift 3.42ratio

 

i daily my  truck on 35s and it’s all highway so I want to swap my diff gears from 3.42s to say a 4.56 or around that range for less transmission strain and to possibly go to a 37” tire eventually 

 

i cant down the truck for more then a weekend so what I want to know before I get to deep is if I do my rear first and my front a week later will any unknown sensors detect 2 different ratios and shut me down or will I be ok for 500miles in between as long as I’m NOT using 4x4? 

davester Senior Enthusiast

davester

Posted
Posted

Note: the following is predicated on having a "normal" 2wdhi/4wdhi/4wdlo/neutral transfer case, not one of the autotrak or awd ones.

 

There are no sensors to detect the different gear ratios.

 

I would unplug the electrical connector to the front diff actuator (that locks the front axle), and tape up both ends so crap doesn't get in them.  This prevents the possibility of a problem if the truck were to go into 4wd, as with it unplugged, no power gets to the front wheels in 4wd (a stub axle in the front diff just spins at the "wrong" rpm).

davester Senior Enthusiast

davester

Posted
Posted

You might try to find out if your front axle works the same as what I described (actuator connects the passenger side axle together when 4wd is engaged, and disconnects it in 2wd mode), and if so, then unplug the actuator.  If it doesn't, then I don't know what else you could readily do to prevent activating 4wd, maybe removing the fuse for the system would do it, but I don't know.

MarcuM Enthusiast

MarcuM

Posted
  • Author
Posted

That would be great if that’s the case 

If it was a older truck then I wouldn’t second guess it but these new trucks with stabilitrak and all the monitors and sensors I would be screwed if I pull my old diff and put new one in and it limp Modes lol

 

i know the driveshaft will turn freely when truck is in park and turned off 

SierraHD17 Senior Enthusiast

SierraHD17

Posted
Posted

It has no idea what axle ratio is in the differential beyond what is written to the ecm and tcm when you tune it which you need to do anyway.  Its gears in there... that's it.  Wheel speed is accomplished from the outer end of the axle shafts at the wheel  bearing with a reluctor ring. I have 4.56s in my own 2017 lol.

MarcuM Enthusiast

MarcuM

Posted
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Posted

How do you like yours ?

6th is pointless in my truck at 70mph it’s 1500rpm and trans temp raises a few degrees so I leave it in 5th at 2000 and temps go down 

 

My truck has 35s with 10-11” of lift and it needs 37” tires bad lol

FlipZ71 Enthusiast

FlipZ71

Posted
Posted

You wont have an issue.  I did the same when I went to 4.56 

 I dropped the front drive shaft out as a precaution 

MarcuM Enthusiast

MarcuM

Posted
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Posted

I been shopping around but I’m assuming the 2016 5.3 3.42 is a 12bolt 9.5” ?

MarcuM Enthusiast

MarcuM

Posted
  • Author
Posted

Did you swap out the hole unit in the rear ?

 

i don’t off road or abuse the truck any it’s a pavement princess lol

 

im on the fence about buy a trutrak or somthing else or leave the oem locker alone since it’s functional still 

other then a chance of snow here in Wv it won’t be a must need I don’t think 

 

SierraHD17 Senior Enthusiast

SierraHD17

Posted
Posted

I would not reuse a Gov lock under any circumstances.  I run Detroit Lockers in all my trucks even if they are pavement only.  It's more or less personal preference.

MarcuM Enthusiast

MarcuM

Posted
  • Author
Posted

Got another question 

I ordered everything from Yukon and had shipped next day air and everything looks right but I’m seeing on my tracking sheet that the master install kit says it is for a 14bolt cover 12 bolt ring 31spline axle 

mine is a 12 bolt cover I believe as well as a 12 bolt gear but other then the gasket will all the pinion bearings and shims fit or is that a complete wrong kit?

hopefully it doesn’t cost me the weekend sending back for the right kit smh 

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