246 tcase questions

[Matthew Jeschke]

Pulled my transfer case. It is a 246. I am swapping transmission... curious if there is anything I should know while I have it off..

Video

also I busted the vent elbow. Any tips there. I need to get broken bits out and put new elbow on.

 

[rockola1971]

Inspect the passenger side rear of the Tcase for the famous pump rub pin holes. How many miles is on your Tahoe? Do you know any history of the Tcase? It may be time for a new chain. You dont want to find out the hard way that the chain has stretched. That lesson will destroy your Tcase when it slingshots out and is peaking out of your case. The parts for rebuild arent too bad, especially if you dont have auto 4wd and dont have to buy the clutches for auto 4wd. There is a plate that runs around $25 to prevent future pump rub. If you dont replace that Tcase output seal, dont be surprised that it starts leaking Tcase fluid out at the driveshaft. The flat seal between tranny and Tcase must be replaced. This is what keeps the fluid in the tranny. Fluid is sprayed just forward of that mating surface in the tranny to lube your OD clutches and output bushing.

 

[Matthew Jeschke]

I have the auto 4wd / clutches.

I suppose I could rebuild the t-case... if is only a weekend project... it was super easy to drop. I was really surprised. My long term plan was to find another NP 246 t-case and rebuild it then swap it in for mine... Rebuild my original and sell it.

Not sure if you watched the video... pretty sure that chain has stretched. I can spin the front driveshaft output on tcase and bit a bit of slack has to be taken up before the rear output / input spins. I'd say 1 degree of so, just enough to make a noise and feel by hand. I have 250k miles on chassis. most everything has been rebuild by me outside of that t-case.

I had looked at rebuild kits... Any clue where I can get a good all in one rebuild kit?

 

[Matthew Jeschke]

I wonder if I just open the case, put in the pump case saver and a new chain. Then call it a day. I couldn't imagine there would be much wear anywhere else, especially on the clutches. They hardly get any use. There's no wiggle in my shafts... They all appear to be pretty solid so assuming bearings are good too.

 

[exp500]

Always open and inspect before you order parts!
Clutches wear alot in Auto mode. Almost zero in standard 4x4 or not use.

 

[rockola1971]

I wonder if I just open the case, put in the pump case saver and a new chain. Then call it a day. I couldn't imagine there would be much wear anywhere else, especially on the clutches. They hardly get any use. There's no wiggle in my shafts... They all appear to be pretty solid so assuming bearings are good too.

If the chain has never been replaced then I guarantee it is stretched with 250k on it. Bearings are worn with 250k on them! If you have to open it up then I would replace at a minimum the chain, seals and bearings, install pump rub plate. But me personally If Im going to open it up then Im doing it all and be done with it. Rebuildable cores are cheap enough if you have to have your vehicle on the road now, just install your current unit and buy a core(car-parts.com) to rebuild then swap out when convenient.
The only "special" tools you will need is internal/external long reach snap ring pliars and bearing/seal driver kit (harbor freight).

Chain, bearings and seals, clutches here: https://www.allstategear.com/NP246-Transfer-Case-Parts-s/1553.htm
Pump case saver plate here: https://www.amazon.com/s?k=np246+pump+saver&crid=323QSF1LL9GKJ&sprefix=np246+p,aps,150&ref=nb_sb_ss_ts-doa-p_1_7

 

[Matthew Jeschke]

Awesome, I will snag a rebuildable core, qnd do this after TX swap is finish. Just want to get rolling again. I also have a steering gearbox to rebuild and my bleeping ac went out again.

 

[rockola1971]

Awesome, I will snag a rebuildable core, qnd do this after TX swap is finish. Just want to get rolling again. I also have a steering gearbox to rebuild and my bleeping ac went out again.

Check your valve cores at your low and high side ports. Usually its the low side since that is what is hooked up to and messed with the most to charge a system. The charging hose will knock the valve core loose when rotated while connected.

 

[Matthew Jeschke]

Anybody know if the splines off NP 246 with older serial number would fit my 2001 Tahoe?

I found a guy selling one for $175. He says it works fine. I may just swap this onto my truck and leave my original for rebuild if this one is funky.

Tag is the transfer case from a 2001 Suburban.



Tag from my transfer case. My Serial number is 01. The one above is 99. Assume that's the year? Otherwise, other pictures look the same. They also have same connectors.

 

[exp500]

Check interchange- car-part.com