2007 with 310,000 miles. Recently swapped transfer case with another 07 because I believe I have the fork issue - was stuck in 4-lock until I reversed, then it disengaged with a rather large "clunk". Decided to swap while I rebuilt my original.

I have the new-used one in. The only difference is the new-used is a 2007 pre-fluid fill design change, so I need to add the extra fluid in the sensor hole. My original is the post design change.

New-used case does not seem to engage the 4 Hi lock - no noise, no clunk, and no extra "binding" felt in the steering wheel. However, when I engage 4-lo, the transfer case DOES lock in. It also stays locked when switching from 4-lo to 4-hi lock. When switching to regular 4-hi, I need to reverse to disengage the lock, but there is no noise when it does disengage.

My question for those who have experienced it, does this sound like the usual shift fork problem? It's just a little weird that the new used unit has the same symptoms as my original. Supposed miles on the new used was 160,000. Just covering my bases. I am gearing up for a rebuild of my original transfer case. I have a new aluminum shift fork ready, but I am prepared to find I need a new chain or bearings. Also have a new screen pick-up for the rebuild.

NO other issues with BCM or other electrical that I am aware of. Lights on the transfer case button work as expected - flashes while shifting, then stay illuminated.

 

Good video on YouTube about t case rebuild. Fellow covers everything.

As far operations go of current t case seems a bit odd. I agree it should go smoothly from each setting. I guess do the the rebuild quickly and swap.

 

Shall we assume you replaced the Transfer Case with the same case your truck had originally???? BW 4493 for the BW 4493, or BW 4494 for the BW 4494? They use different TCCMs.

 

@Doc Olds Yes, same ratio. Both are an NR4/4493 case. Not that I want to swap, but that is good to know there are differences in the TCCMs - I didn't know that.

I just thought it was weird that I'm having a similar problem, and I want to make sure there isn't something obvious that is outside of the transfer case itself. I have read elsewhere that some cases that have not been used much need to be "exercised", but I'm a little skeptical of that. Other than it staying locked when going from 4-lo to 4-hi, there are no excessive clunking or other sounds. It does seem to shift very nice. And so far I have always been able to get it to disengage by going in reverse and steering left or right. No sound when it does disengage though.

I imagine that the servo motor simply rotates further to engage the 4-lo, so I can see how it can be the same shift fork problem, but just in case there might be something else, I posted here.

One last thing is I swapped the servo motor along with the transfer case. Don't know if that could be the issue, but I do still have the servo motor from my original case.

@Happy Hummer thanks for the reference to youtube. I believe I know the video you are referencing, and I have watched it a few times. I don't know when I will get a chance to open my original case up - I swapped so I wouldn't be in a rush

 

You could very well have the plastic fork in your temporary used replacement. I would bet most of the 06s and 07s had them from the start.

 

Thanks Doc, I imagine this is my issue x2. Like I said, it was just a little weird. Hopefully I don't have any problems with the new-used for the time being.

 

So, if I'm understanding you correctly, it will NOT go from 4-HI to 4-HI-Lock, but it WILL got from 4-LO to 4-HI-Lock, right? Will it then go back to 4-HI (unlock), or do you have to go to 4-Lo first?

 

Sorry, I might have been confusing.

The unit (appears) to be shifting fine. But,
When going from 4-HI to 4-HI-LOCK, it does NOT physically LOCK.
When going from 4-HI to 4-LOW-LOCK, it DOES physically lock.
When going back from 4-LOW-LOCK to 4-HI-LOCK, it STAYS locked.
When going from 4-LOW-LOCK to 4-HI to 4-HI, it STAYS locked, until I drive in reverse to get it to disengage.

During all these shifts, the lights operate as normal, with no indication that the case suspects a problem - it believes it is shifting properly.

After typing this up, I guess I have not tried switching from 4-LOW-LOCK to 4-HI-LOCK, then reversing to see if it will disengage. But at this point, I realize I just need to get into my original case and R&R as needed.

 

Did you clean the switch/connector contacts?