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203 tranfer case grinding(UPDATED WITH VIDEO 2-8-2011)

barneybasher1010

barneybasher1010

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The case is grinding in every position. It sounds like it is in between gears or something. I took off the linkages and put the case in low and high manually and it still does it. It sound like it is coming from t he rear of the case. With the truck jacked up it does not do it until there is a load on it, like when I step on the brakes. There was NO metal or chunks in the case. :confused: HELP!
http://www.youtube.com/watch?v=_hWrlah2k44
 
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r u sure it's not the chain that you are hearing. 203's are notorious for having chains that become stretched.The rear of a 203 has a type of differential in it. Have you tried it in the LOC position?
Either it sounds like you have to remove the T-case and go through it.You might consider a 205.
 
amarillok5 said:
r u sure it's not the chain that you are hearing. 203's are notorious for having chains that become stretched.The rear of a 203 has a type of differential in it. Have you tried it in the LOC position?
Either it sounds like you have to remove the T-case and go through it.You might consider a 205.
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It does have a part time kit in it. It does it in every position. The rear yoke jumps around when it is grinding.
 
Oh! That's not good.I heard you had to be real careful about shims.Here is some info on the NP203.It's a rugged t-case when it's stock. I've heard some part time kits are better than others 4wheeloffroad.com/howto/47538/index.html
 
amarillok5 said:
Oh! That's not good.I heard you had to be real careful about shims.Here is some info on the NP203.It's a rugged t-case when it's stock. I've heard some part time kits are better than others 4wheeloffroad.com/howto/47538/index.html
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The kit was in it already when we bought it(last year). It just has me puzzled with no metal shavings in the oil.
 
barneybasher1010 said:
The kit was in it already when we bought it(last year). It just has me puzzled with no metal shavings in the oil.
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It's just hard to say what it is with out looking at it. but it sounds like something is very loose in there. It's a good thing that there's no shavings in the oil but still there is something very seriously wrong with ur 203. Nothing you can't tackle though.

It's gonna take some work. You might be able to get away with just removing the back part of the t case. Be aware though that there may be a magnet some where near that drain plug that may have gathered shavings.

Let me ask you this. Is this blazer a daily driver? Do you have huge tires on it? Where I'm going with this is if this K5 sees alot of rough action then a swap to the 205 may be worth your while.

203's make good daily drivers and occasional 4x4 activity, But the 205 is the choice of champions.
 
amarillok5 said:
It's just hard to say what it is with out looking at it. but it sounds like something is very loose in there. It's a good thing that there's no shavings in the oil but still there is something very seriously wrong with ur 203. Nothing you can't tackle though.

It's gonna take some work. You might be able to get away with just removing the back part of the t case. Be aware though that there may be a magnet some where near that drain plug that may have gathered shavings.

Let me ask you this. Is this blazer a daily driver? Do you have huge tires on it? Where I'm going with this is if this K5 sees alot of rough action then a swap to the 205 may be worth your while.

203's make good daily drivers and occasional 4x4 activity, But the 205 is the choice of champions.
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Its in a 75 K15 with a BBC and is a weekend mudder basically. It has 35" tires on it.
 
Sounds a lot like it could be the collar that engages when it's put in the loc position. Mine is doing it right now sometimes when I'm coasting in 2, I think it's because I didn't bother to get the endplay correct when I slapped it back together last winter. Could also be the crappy part time kit the PO put in there...I think I found the spider gears in one of the boxes that came with the truck though.

I have the case out right now cuz I just rebuilt the th350 with new clutches and all that good stuff. When I go through the 203 probably this comming weekend I'll try to get you some pictures or some better info if I can remember. Wish I had the time to go through my 205 and make an adapter right now. I'm avoiding much effort or money in the 203 because I'm holding out for time to do a doubler. Bugs me to put the 203 back in.

You can investigate what's going on by removing the rear driveshaft and the aluminum tailcone from the case while it's in the truck. Won't even spill out that much oil. You can get to the side gears/spiders (or part time kit) from there. I am 99% sure it's going to be something there, the rest of the case is just a big cog attached to the front output, the chain, and the gear reduction up front. Depending on your floor, you can even change the chain with the gear reduction still bolted up to the tranny adapter.

If you end up dealing with needle bearings, hold a cup under the output shaft and rotate it. They will spin towards the back of the case as you rotate and fall right in to the cup. Just coat them with grease like Assembly Goo when you put them back in, they'll defy gravity with good grease pretty easily. If you drop some in the case, you can just remove the lower cover that supports the front output and reach in there. There's a relatively good amount of room in that chaincase to get fingers or a magnet inside.

If you do pull it, you might be able to do it in halves (chaincase and gear reduction seperate). It's a lot more messy, but it doesn't weigh 260 lbs that way either.
 
Oh! Could be rear output bearing. Big problem with the part time is that the chain no longer throws oil back there (also why you DON'T run gear oil).

Btw if it's the chain, it will pop audibly when you load the front driveshaft and it jumps teeth. Similar to a locker when you're turning. It will start doing that when it's under load quite a while before you notice any other symptoms unless you are only street driving and not really working the front end.

If you find cracked needle bearings I have extras I can mail you if you can't find any local. Not worth spending money on one of those turds and the parts are not available really except what it shares with other np cases.
 
barneybasher1010 said:
Heres a video. It shows the rear and front yokes jumping with what it sounds like.
http://www.youtube.com/watch?v=_hWrlah2k44
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Looks like it's partially engaging the 4 lock gear in the back. I forgot to mention this, disconnect the shift rails from the shifter. Crawl under there and engage/disengage the center diff that way, so you're only feeling the engagement inside the case. Those shifters are terrible and frequently get screwed up so that they are only halfway engaging. If that's not it, unbolt that aluminum tailcone and do some investigation. Post some pictures of the center dif in there if you get stumped, cuz that about the only thing that could be messed up and cause that behavior.
 
owenst7 said:
Looks like it's partially engaging the 4 lock gear in the back. I forgot to mention this, disconnect the shift rails from the shifter. Crawl under there and engage/disengage the center diff that way, so you're only feeling the engagement inside the case. Those shifters are terrible and frequently get screwed up so that they are only halfway engaging. If that's not it, unbolt that aluminum tailcone and do some investigation. Post some pictures of the center dif in there if you get stumped, cuz that about the only thing that could be messed up and cause that behavior.
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I already disconected the shift rails. and messed with them. It does not change.
 
JeremyK5 said:
u need to drain the t-case first, if u find an ultra light amount of supper fine metal in it u ur spider gears r stripped, if u find a ungodly amount of metal in the 13w30 oil then ull need a new t-case. ive rebuilt 5 of these case now and built one 203 to 203 doubler and im willing to say u need a new t-case period.
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NP calls for straight non-detergent 30 weight in the 203. It will resist foaming from the chain.

You can investigate the spider gears without draining out the 7 quarts of oil. Not that that's not a good idea too, but opening the passenger side of the case isn't going to help you see the spiders on the drivers side of the case.

If you have a part time kit, you won't have spider gears anymore FYI.

http://www.offroaders.com/tech/Diagrams/np203.htm

I'm pretty confident this is going to be endplay or something related to the locking side gear up front (17). If it has a part time kit, the spiders are replaced by a spool essentially, and in 2wd the chain shouldn't be moving at all, and it certainly wouldn't cause half-engagement of the rear driveline. I suppose a partial engagement inside the gear reduction would cause what was in the video, but I don't think I've ever seen anything broken inside one of those.

35"s aren't a big deal on that case BTW. I had a '79 Ford that I commercial plowed with for years in Alaska that had a 203, and I'm currently running one in my trail rig that's on 40s with 4.10s in the axle. Destroyed the th350 in there, but the 203 is fine.
 
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More pics.
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My supervisor taking a nap!
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Yeah looks like your case is toast.
Good thing is these case are a dime a dozen, unless you wanna switch to a 205 then hit me with a PM.:thumb:
 
owenst7 said:
Well of course he's tired after you made him bench press that huge tcase out of the truck!
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He tries to help all he could. He was cold so I told him to sit in the sun and five minutes later he was out. He didn't even wake up with impact right next to him when I toke the yoke off!
 
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