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4x4 transfer case shift

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GMC-AT Senior Enthusiast

GMC-AT

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2000 Silverado -  manual shift 4x4

 

It's pretty hard to get the truck to shift out of 4x4 low.  Even if I pull the truck forward and back.  Is there a reason for this, is there a video on how to lube the linkage mabye?    4x4 high to 2x4 works fine.... no issue there. 

GMC-AT Senior Enthusiast

GMC-AT

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I should add.. I do put the truck in neutral before trying to shift to 4x4 low... 

newdude Senior Enthusiast

newdude

Posted
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I'd crawl under and spray up the linkage and the lever.  Give it a good lookover for any debris or anything that would keep it from being freed.  Probably never has been in 4LO for a long time LOL.  Got used to 2hi and 4hi. 

Supreme Pizza Senior Enthusiast

Supreme Pizza

Posted
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Might be worth checking the transfer case fluid level. Also, as stupid as this sounds: I would recommend reviewing the transfer case shifting instructions in the user manual. I'm often surprised about the little quirks that each T-case has. Some say shift slow, some say shift fast. Others say lock the e-brake, some say to be rolling at 1-2 MPH during the shift. 

GMC-AT Senior Enthusiast

GMC-AT

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Your right.. I actually just did read the manual, and it says I should be rolling 1-3 mph with Transmission in N when shifting in and out of 4 Low. I wasn't doing this... I was shifting with the truck stopped and not rolling.  Likley the issue.. thanks. 

carkhz316 Enthusiast

carkhz316

Posted
Posted

Part of the reason for the more difficult shifting is that the Range fork (1 of 2 forks in the T-case) is moving in tandem with the Mode fork, adding to the effort required to move all the parts inside. Also, there is no synchronizer for the shift collar for high/low range like there is for the 4WD output, adding to the effort required. So yes, A gentle roll with the transmission in neutral will make it easiest on you.

 

The pics are from a NP263 I just rebuilt due to being run dry caused by a pump rub failure (check your oil level kids!), but they're virtually identical to yours inside. The first pic is the mode fork (2wd/ 4wd) and the second pic is the range fork (Hi/ Lo). The collar I mentioned is just the left and above in the second pic. This shifts in and out of the planetary gear set to the left in the picture to give you your two speeds.

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