NP246 Auto 4wd Transfer Case Owners Beware!

[ShookieJay]

Just wanted to share my experience with y'all and hopefully save someone the headache of blowing up their transfer case. So I bought my '03 Tahoe about 6 months ago with only 69k miles. As of writing, I'm sitting at just over 74k. As long as I've owned it Ive heard a bit of a chatter sound from the front end. After inspecting, cv axles, wheel bearings, and driveshaft, I couldn't figure out where the noise was coming from, so I brushed it off. Well... After completing a 1500 mile round trip, that quiet chatter turned into a very loud, crunchy sounding chatter. Turns out the transfer case chewed itself up. The reason? The oil pump rubbed a hole in the case and all the oil drained out. Moral of the story, CHECK YOUR TRANSFER CASE OIL! And if you're lucky enough to catch it before it makes a hole, they make a "case saver" that goes between the pump and the case. Would strongly recommend anyone who intends to keep their rig for any length of time to install this part and save yourself from the catastrophic failure that could otherwise result....

 

[Joseph Garcia]

Thank you for this insight. Much appreciated.

 

[mrhp]

Old news in the t case world, but new to you. Sorry for the bad luck.

 

[rockola1971]

Yup. A common knowledge to us experienced with the NP246/NP246E case. The fix is stupid easy and cheap to do too.

 

[asand]

Mine did the same thing anda busted a hole in the case side after toasting the bearings and chain. My fix was an NP241 swap.

 

[Tonino]

Just wanted to share my experience with y'all and hopefully save someone the headache of blowing up their transfer case. So I bought my '03 Tahoe about 6 months ago with only 69k miles. As of writing, I'm sitting at just over 74k. As long as I've owned it Ive heard a bit of a chatter sound from the front end. After inspecting, cv axles, wheel bearings, and driveshaft, I couldn't figure out where the noise was coming from, so I brushed it off. Well... After completing a 1500 mile round trip, that quiet chatter turned into a very loud, crunchy sounding chatter. Turns out the transfer case chewed itself up. The reason? The oil pump rubbed a hole in the case and all the oil drained out. Moral of the story, CHECK YOUR TRANSFER CASE OIL! And if you're lucky enough to catch it before it makes a hole, they make a "case saver" that goes between the pump and the case. Would strongly recommend anyone who intends to keep their rig for any length of time to install this part and save yourself from the catastrophic failure that could otherwise result....

Good Post Jay. I heard about that and check mine (135K miles) every so often and definitely between oil changes. I've always had a conditioned reflex to look under the family vehicles just walking by them in the driveway looking for fluid leaks. Good practice.

 

[mountie]

" Case saver" ?? I haven't heard about this..... ( I am into preventative maintenance )....
What do I need to know? ( '05 Yukon with 166,000 miles).... no drips, except for a tiny drip from my oil pan...

 

[George B]

" Case saver" ?? I haven't heard about this..... ( I am into preventative maintenance )....
What do I need to know? ( '05 Yukon with 166,000 miles).... no drips, except for a tiny drip from my oil pan...

 

[Fless]

" Case saver" ?? I haven't heard about this..... ( I am into preventative maintenance )....
What do I need to know? ( '05 Yukon with 166,000 miles).... no drips, except for a tiny drip from my oil pan...

@George B beat me to it, but here's another.

Transfer case leaking!

I've found Zep products to be great for degreasing. Orange Concentrate and Green Heavy Duty. I found Home Depot sells them but I started using their products in Industrial Applications. I had a Oil Sender blow and it coated the entire under carriage with oil. I sprayed it on concentrated, waited...

www.tahoeyukonforum.com

 

[Matthew Jeschke]

I just rebuilt mine. Had 250k miles on it. Thankfully never worked that hole in it. There's a little metal clip the factory puts on between the case and the pump. This is to keep the pump from rubbing through the case. However, that clip doesn't always stay in place, or hold up. it's not much of anything and a terrible solution.

When I rebuilt my case I put in a different pump half. Like @Fless shows above. I bought my from merchant automotive. However, I would imagine a generic one off ebay or amazon would work just as good. You can get that or a case saver, which is even cheaper. Sad that the t-case is built REALLY well with exception of that pump rubbing through. They're SUPER easy to pull & rebuild @rockola1971 contributed to that thread greatly linked below:

Pulling off the Perfect NP246 Transfer Case Rebuild

Ah thanks, yeah I just double checked that. Might have been lighting. There's no gap on outer diameter of seal anywhere. I'm ordering a new one, especially since my friend's seal in the same kit just failed in same way. Are you pretty careful about using a tool? I think I'll build a tool out of...

www.tahoeyukonforum.com

I'd tear down your replacement and at least throw in a case saver. I upgraded a few things, otherwise they're pretty well built from factory.