found a lot of posts about this case and people looking to replace their broken ones, but nothing that answered my question exactly so here we go.

Barney's transfer case decided to blow up on me while driving down the highway this morning. and to answer all of your first question, no, i was not in 4WD on the pavement. just 5th gear cruisin and heard something break, then my 4WD shifter started dancing back and forth. this is how i drove it home





i've been looking for used t cases and remaned ones online being its sunday and the yards are closed. mine is a 231D with a 272 ratio, but i seem to find a lot out of durangos and rams that are all 231D's but have HD or even EHD after (but have the same ratio). I found on ebay some rebuild kits that are "upgrades" to make your t case "Heavy duty" that have 4 or 6 planetary carriers instead of just 3 like mine and i'm wondering if thats all they are, but OE. assuming that the input and output shafts have the same number of splines (or i could even swap my shafts around into the new case since giving it all new gaskets would be a good idea anyway) do you think they should bolt up and work just fine?

Or, Gm runs the same 231 with a 272 ratio but the model number is 231C instead of 231D. those are a little more college budget friendly, so again if i could swap output shafts any reason why they shouldn't work? (yes, i cringed a little typing that...)

Also the issue of Auto to manual. Mine is a 5.2 with the 5spd and manual 4WD linkage, no vacuums as i'm sure most of ours are.

I have a guy that works for dodge dealer in KC hopefully looking into it tomorrow, but i'd like to hear from you guys as well. thanks.

 

I had my T-case do the same exact thing that yours did, in fact it looked just about the same if not a bit worse. Whatever you end up doing get the joints checked on your front drive shaft. My high velocity joint is what caused mine to blow up because it had gone bad.

 

The 231C uses the same bolt pattern where it connects to the transmission, but it's clocked differently, so it won't work. A 231J should work, but it won't have the wider chain that the 231D (or maybe it's just the HD) has.

 

here's a bit from drivetrainparts.com:
"Jeep, Dodge and Chevy versions all use a 6-bolt circular bolt pattern. This pattern is non-symmetrical and will only bolt up one way. Jeep units and Dodge units are general interchangeable, however Chevrolet units are not. While GM uses the same 6-bolt patter, they have it rotate approximately 90 degrees from that used by Jeep or Dodge.

NP231 transfer cases come with either a 21 or 23 spline female input. The 21 spline shaft is frequently found in 4 cylinder applications and the 2.8L V6, While 4.0L 6 cylinder and 8 cylinder applications always used the 23 spline input shaft. The GM/Chevy NP231 is supplied with a 27-spline female input"

Basically exactly what you were saying Tom. the only thing i'm still not sure of is the HD. from what i've read, the only difference is gear and chain width. One of my teachers down here at Pitt State used to be a training instructor for chrysler so i've e-mailed him asking for some help. but unfortunately i sent him the wrong phone number so i'mjust waiting for him to try calling again lol i'll keep you guys updated.

 

I think the HD has 6-pinion planetaries (instead of the usual 3), but I'm not sure.

 

I found a t case out of a 98 durango 5.2

http://joplin.craigslist.org/pts/3837221493.html

231D HD
Assy # 5210 5242 (he told me 5242 on the phone, looks like it MAY be 4242 instead?)

same 272 ratio obviously.

The one i'm currently running (97 dakota 5.2) is

231D
Assy# 5210 5365AB
272 ratio.

without being able to find parts diagrams to compare them side by side or buying this one and pulling mine then counting splines, can anyone tell me if it should work? Also, teacher is in germany until the 8th so he's not gonna be able to help me out for a while

 

Oh boy this is getting tricky..... found out the reason the yards were telling me that the 96-97 dakotas had a very specific transfer case. the output shaft is a smaller diameter than the new one out of the 98 durango and it (the old t case/ slip yoke on the drive shaft) is also keyed to only go on one way. looks like i'm walkin to the bank to get some money for some snap ring pliers to see if i can swap output shafts. if that won't work, looks like i'm gonna have to find a rear drive shaft out of a 98-99 dakota. only thing is, when i looked for used ones on ebay none of them have the vibration dampener attached to the front slip yoke like mine does. guess its not that big of a deal, right?

 

this is in Arizona but im guessing he would ship it

http://phoenix.craigslist.org/nph/pts/3856705572.html

 

OOOOOOHHH SHIIINY. the serial number puts that one as being manufactured in '00 so it's probably gonna have the same number splines and everything that the one i picked up has... assuming it was from behind a v8. i was able to pick the new one up for 75 bucks and the guy claims it was rebuilt shortly before the durango was totalled in the joplin tornado. seals all look to be in really good shape but i'm still gonna throw a rebuild kit in it since im tearing it down to try and swap shafts anyway. plus, its an HD, which means MOAR 4X4!!!!!!! lol or just more broken front difs... guess we'll see after my next paycheck.

 

Well, finally got the new t case torn apart
Keep in mind that this is the 231D HD, assy # 5210 5242

100_0571-1.jpg

I thought that the HDs were supposed to have 4 or 6 planetaries? cuz unless i shouldn't be in college, i only count 3...



I also thought that they were supposed to have a wider chain? because old and new front drive gears are the same...



Now, in the 231 t cases apparently some use a 4.3" input shaft and some use a 5.3" shaft which also affects the input bearing needed (if anyone esle is using this thread for a rebuild. the 4.3" shaft uses a .940" wide bearing where the 5.3" shaft uses a .630'' wide bearing.) mine is the 4.3" shaft



Now upon further inspection, my input bearing is clearly not .940" wide... i can tell that even with dead batteries in my calipers. i thinking that maybe when it was rebuilt previously they may have been given the wrong kit and not paid attention?



Lastly, the output shaft on this has a 32 spline count and is just a fraction shy of 1.4" in diameter.



i guess the next step is to pull mine and see if i cane make one good one out of the two with hopefully the correct rebuild kit.

i'll keep you guys updated

Also. here's where i was getting my info from about the shaft and bearing pair sizes. i suppose that they could maybe gotten their parts list mixed up? but i feel pretty confident that i found that same info somewhere else as well.
http://www.midwesttrans.com/NP231.html