MP3023 Transfer Case Grinding/Chattering

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DaveO9

DaveO9

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That's a pocket bearing and they're known for cracking on these, which I would wager is what's happened to yours. The root cause is a broken snap ring groove on the rear main shaft that forces the shaft into the planet, breaking the bearing. I only know this because I had a transfer case problem on my 2002 and remembered this detail from my troubleshooting on it. This video shows it well, starting at 5:00.

Thanks for the info and vid link. seems like a plausible explanation. Do these problems continue to the MP t-cases of late 2000s? I think your 2002 would have been an NP261? Just trying to figure out if this is a systemic problem with the MP3023. I purchased a used one from LKQ today - 120K miles for $265. 6 mo/6000 mile warranty. I pick it up tomorrow and hopefully will install same day. Fingers crossed I don't have same problem with the new one in 6 months + a day.

At least the MP t-cases don't have the pump rub problems that the older ones had.
 

Geotrash

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Thanks for the info and vid link. seems like a plausible explanation. Do these problems continue to the MP t-cases of late 2000s? I think your 2002 would have been an NP261? Just trying to figure out if this is a systemic problem with the MP3023. I purchased a used one from LKQ today - 120K miles for $265. 6 mo/6000 mile warranty. I pick it up tomorrow and hopefully will install same day. Fingers crossed I don't have same problem with the new one in 6 months + a day.

At least the MP t-cases don't have the pump rub problems that the older ones had.
Yep, my 2002 had a different TC, but I was having problems with it in 2016 so I just remembered coming across that video in my research.
 
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DaveO9

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"New" T-case from LKQ is in and rig is running and driving - no noise! $275, from a silverado with 119K. Install went pretty well except for the fact that exactly .5 seconds after I got it seated on the adapter I remembered I needed to install the gasket. Back down to the ground on the trans jack so I could add that in. I'm still not sure I understand the need for a gasket there. There's a v-groove in the adapter's mating flange so it's definitely not going to hold any fluid that leaks out of the trans. Oh well, it's in.

It took less fluid than I thought. I originally bought two quarts, but I used part of one to do a minor flush, and then a bit leaked out through the output at one point when I got it too catywampus. (I added fluid before install in the hope of avoiding use of a transfer pump) So I was expecting to have to go get at least another quart, but after everything was installed, I pulled fill plug and fluid dribbled out for several minutes so it seems like I had too much in there when I was expecting there to be not enough.
 

Geotrash

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"New" T-case from LKQ is in and rig is running and driving - no noise! $275, from a silverado with 119K. Install went pretty well except for the fact that exactly .5 seconds after I got it seated on the adapter I remembered I needed to install the gasket. Back down to the ground on the trans jack so I could add that in. I'm still not sure I understand the need for a gasket there. There's a v-groove in the adapter's mating flange so it's definitely not going to hold any fluid that leaks out of the trans. Oh well, it's in.

It took less fluid than I thought. I originally bought two quarts, but I used part of one to do a minor flush, and then a bit leaked out through the output at one point when I got it too catywampus. (I added fluid before install in the hope of avoiding use of a transfer pump) So I was expecting to have to go get at least another quart, but after everything was installed, I pulled fill plug and fluid dribbled out for several minutes so it seems like I had too much in there when I was expecting there to be not enough.
Way to go! Glad you got it all buttoned up. My guess is that the gasket is there to prevent fretting between the two metal parts.
 
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DaveO9

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Just to close the loop on this, I finally got around to disassembling my old t-case to see what happened. Looks like the planetary gear set failed. Also the input bearing seems to be toasted, but maybe that was collateral damage. (or vice versa?) The pics show a slight crack in the carrier at one of the pin locations, and two of the planet pins failed. One is so loose that it feels like there are no bearings at all in there. I still can't believe we made it home (500 miles away) with it like this.

Everything else in there seems to be fine, including the viscous coupling. Throw it up on CL for $75 for parts and see if I get any takers? IMG_4305.jpegIMG_4304.jpegIMG_4301.jpeg
 

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