Was this ever answered? My Transfer case on my 2000 z71 finally got the infamous pump rub hole and will need to be replaced soon. Wondering if I can get a later model np246?

TIA

 

I know that this is an older, unanswered thread, but it is the one that shows up on the Google search, so I'll add what I remember from rebuilding them. (It's been almost 2 years) internally, the clutch packs are different thicknesses. I would need to have one open to check for washers, etc that might need changed to meet the proper clearance. The actuator arm is different in the ramps and one is spline drive to match the proper encoder. The clutch apply fork is also different, from what I recall. Many internals are the same, though, but I don't recall if you can swap between the front case , or if they need to match the encoder bolt pattern. If you want to do the update, the easiest way is to find a donor vehicle and get the case, the module behind the selector panel in the dash, and the encoder pigtail. It's a good idea to grab the selector panel as well. Afaik, the speed sensor setups are the same, but the module is programmed different.

 

Yes you can. I have done it. There is a newer design Owyhee that goes in the case pushing the clutches apart and they ate put together with less clutch preload allowing them to free spin. The downside is then in auto 4wd it slips then grabs. The older ones I think were smoother in auto mode. I would guess If you put a video camera under the truck the shaft probably still spins a bit going down the road.

I modded my early np246 so that in 2wd mode, clutch in the least amount of apply had clearance like an automatic transmission clutch. I had the newer design clutch apply spring and modified the ramp on the cam that in turn applies the clutch fork. It's not as loose feeling as the newer ones but in auto mode it's smoother and not as abrupt of an engagement. It works well, had it on 2wd dyno no issues. In my set up I have no front axle disconnect. I have pics of the mods somewhere, it was my little secret.

 

Does anyone know where to buy the newer design clutch pack that megabuddys wrote about in his post?

 

I know it's not what you asked, but I have a good one (came stock on my 2006 rcsb 1500) with 92K miles on it that has had the input shaft for an 80e installed that I am pulling off my truck if you're interested.

 

I must have wrote my last response on my cell phone.

The new cases are set up with more clutch clearance, I am assuming there is a selective Backing plate (different thicknesses) and there is a clutch Spring that assists in pushing the Apply plate off. I get the parts needed through Cobra Transmission. To have a true 2wd T case, just get the newer one. I modified my older one to do the same thing, all i did was buy the updated return Spring for 20 bucks, then set the clutch pack clearance by modifying the cam that applies the Shift fork. In auto 4wd mode, it will slip the rear tires a touch more before the front engages, similar to the newer ones.

Whatever you do if you do it, dont take the wave washer out of the apply plate. It cushions the engagement.

Someone mentioned different programming between the Newer and older cases. I believe there has to be.

 

The 99-2002 and 03+ have different plugs on the shifter motor. I bought a 246 out of a '02 suburban to go into my '03 Silverado and the plug was different. Also, you cannot swap out motors because the shaft is a different shape.

 

Correct. I learned the hard way as well, bought a NP246 from a 2002 Tahoe, had it rebuilt, new aluminum rear case, 32 spline input, etc. Then found out they won't interchange.


I found out that the shafts are interchangeable, but I just bought a NP241 manual shifted transfer case instead, put the front actuator on a hidden toggle, and cut a hole in the floor, and installed a factory shifter. Pulled the TCCM under the dash and swapped out push button autotrac switch for a 2wd cubbie. Looks all factory/stock now.

 

Is anyone sure about the swapability for the older in newer or vice versa providing the TCCM and wire harness's are used from the same vehicle?

 

Sounds like a huge hassle and headache vs just getting the correct NP246 for your truck.