Help Identify my Transfercase so I can order a new chain

[Big_Mark]

Hi All, 

I need help identifying which particular transfercase (model, year / version) I have so I can order a new t-case chain that is the correct length the first time around. 

I need help because my MJ is a bit of a franken-truck and the PO (now deceased) swapped in the transmission and axles. He didn't say anything about the transfercase so I am presuming it's a stock 1989 NP 271 but as I said I am not 100% certain.

 

Here is the badge on it

 

I think the stamp reads:

231J
5209 9212
12 7 98 3C
272

 

 

Here are some views of it in the MJ.

 

 

 

VIN: 1J7FJ36L8KL434465

 

Any input is appreciated also if you have part numbers please post up, I'm having difficulty finding any replacement chains.

 

While I have it apart, I'd like to replace the seals, oil pump and pulley gears. Again, part numbers would be greatly appreciated thanks for helping me find parts for my winter project!  

[acfortier]

The top 231J is a NP231. The other numbers can be decoded, like in the image on this site: https://www.novak-adapt.com/knowledge/transfer-cases/np231

[Big_Mark]

Thanks man!

 

Parts for the New Process 231 Transfer Case (novak-adapt.com)

[fiatslug87]

Why don’t you put your truck in the registry since you posted it’s VIN already?

[Big_Mark]

On 11/2/2022 at 3:46 PM, fiatslug87 said:

Why don’t you put your truck in the registry since you posted it’s VIN already?

Thought I had already, I'll get ur dunn soon 

 

P.S. here's a useful link How To: Rebuilding A Jeep NP231J Transfer Case (motortrend.com)

 

[Eagle]

That's a 231 transfer case, but it's not out of an '89 MJ. That's out of a late model XJ, with the short shaft output. The tailshaft housing of an '89 would look like this:

 

 

The driveshaft front yoke would go directly into the tailshaft housing, and there wouldn't be that bellows dustcover.

 

[Big_Mark]

Thanks Eagle, this helps me compile my "custom components" list, my guess is the transmission came from the same donor rig.

 

So is this transferase "better" than the original or about the same? In regard to reliability, strength, etc.?

 

There is nothing like owning a grab bag Jeep!

[Airborne Janitor]

1 hour ago, Big_Mark said:

Thanks Eagle, this helps me compile my "custom components" list, my guess is the transmission came from the same donor rig.

 

So is this transferase "better" than the original or about the same? In regard to reliability, strength, etc.?

 

There is nothing like owning a grab bag Jeep!

 

What Eagle said. I have a 97 XJ aw4 auto trans and 231 case and it looks just like your photos. The later model cases are 23 spline vs the older 21 spline, and talishaft housing is different and the splines stick out a few inches more than the older case. I'm willing to bet that the previous owner swapped both the trans and transfercase at the same time (easier). Out of curiosity why are you replacing the chain?

[Big_Mark]

I'm replacing the chain because when I'm in 4wd, low under load there is a "rollercoaster" *Clack* *Clack* *Clack* *Clack* noise that seems to be coming from the Tcase. When I take the Jeep out of 4wd it goes away. Pretty sure it's a sloppy chain whacking the inside of the case.

[AeroNautical]

Is that a casting mark or a crack near the NP gear logo in the first photo?

[Airborne Janitor]

3 hours ago, Big_Mark said:

I'm replacing the chain because when I'm in 4wd, low under load there is a "rollercoaster" *Clack* *Clack* *Clack* *Clack* noise that seems to be coming from the Tcase. When I take the Jeep out of 4wd it goes away. Pretty sure it's a sloppy chain whacking the inside of the case.

 

I had a very similar issue in my XJ and ended up swapping in another t-case, thinking the chain was done. Wasn't the problem tho, it was a broken tooth on the front ring gear. 

[Airborne Janitor]

1 hour ago, PFCLeist said:

Is that a casting mark or a crack near the NP gear logo in the first photo?

 

Good eye, that does look like a crack....

[Eagle]

15 hours ago, Big_Mark said:

Thanks Eagle, this helps me compile my "custom components" list, my guess is the transmission came from the same donor rig.

 

So is this transferase "better" than the original or about the same? In regard to reliability, strength, etc.?

 

There is nothing like owning a grab bag Jeep!

 

Better in some ways, worse in others. No difference in strength.

 

The short tailshaft housing has a seal that rides directly on the tailshaft, so when you pull the driveshaft the fluid doesn't run out. Not a big deal when working under the vehicle at home, but if you experience a rear drive problem on a trail and need to drive using just the front (with no rear driveshaft), there's no worry about losing all the tranny fluid before you get off the trail.

 

The newer ones also supposedly have a true neutral position, for flat towing. I haven't tested it, but what I've read is that on the older ones the neutral position disconnects the engine from the driveshafts, but leaves the front and rear locked together -- which is not good for towing any distance.

 

BUT ... that long, unsupported length of tailshaft hanging out there is extremely prone to driveline vibrations.

[Big_Mark]

Thanks for the feedback, I think that "crack" is just something in the casting.

The only way to find out what the noise is to pull the case, more to follow!

[Big_Mark]

Well I finally got the transfercase out.

the chain was lose and I found a spot where it was dragging on the shifter fork

 

 

Next, read the rebuild guide, rebuild subassemblies, then put it back together !

 

I have my work cut out for me!

[Big_Mark]

I've got a picture of the ID tag.

 

When the PO swapped in the transmission, he must have used the T case as well, wish I had known before ordering my T case rebuild kit, oh well that's all part of buying a truck from some bushes .