Drivetrain issues

[Steph90]

Hope I labeled that right.
But here's the deal.

99 jeep wrangler tj sport

Transfer case

Model # 231 J
Assy # 5209 9211
Serial # 7 24 98 2
Ratio # 272

Ok I guess let me start from the beginning with this headache.

Jeep lost 4lo after he pulled a truck.

The rear end had to be pulled apart and have all the gears replaced inside.

We had it on the road and he was running it in 4hi when the rear went out because it wouldn't move in 4lo or without the 4x4 engaged.

Now I thought we were only going to have to replace the transfer case as it blew to peices coming off the interstate.

After talking to a shop they said they can guarantee that the front drive shaft is bent or locked up.

Im so lost here. I try to find a transfer case and I find a whole bunch of mumbo jumbo about how these things work but no actual guide to what we need.

Im assuming we need a long shaft transfer case. As this is a manual.

Does the assembly number matter. ???

Im trying to keep from spending $500 on a transfer case... and another $300 on a drive shaft.



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[Chris]

As I mentioned in my previous post, all Jeep Wrangler TJ NP 231 cases from the factory are the same except for the input gear. The automatic has a different input gear from the factory than the manual. But that is the only difference whatsoever. Other than that, the transfer cases are the same.

Input gears are a very simple swap as long as you remember one thing. Around 1995 or 1996 (about same time New Process became New Venture) they changed the tooth profile on the planetary gears, the ring in the case half, the planets in the cage, and the sun on the input gear.

So what I am saying, is that it doesn't matter what transfer case you buy, as long as it came from a 1997-2006 Jeep Wrangler TJ, and as long as it's not a Rubicon transfer case (which is a NV 241).

The worst you'd have to do is swap the input gear if you bought a transfer case from a manual transmission model, but that's easy.

As for bent driveshafts, if the transfer case locked up and grenaded, then yeah, I would bet your driveshaft is done for. Post a picture, it will be pretty easy for us to tell!

 

[JP98]

Wow! You have a lot going on. You wouldn't want to normally run the Jeep in 4hi at highway speeds. What does the shop mean by the driveshaft is locked up?

@Chris is right about getting the correct transfer case for the 97-06 TJ and just swap the input gear if need be.

 

[Chris]

The important variations to look for in the 231 transfer case are in the input gear. The 231 comes in 21 spline and 23 spline versions with long, medium (rare) and short variations.

The long shafts protrude 2.1" from the front mounting face of the transfer case. The short version protrudes 1.2". The rare medium shaft protrudes 1.7". You should be careful when swapping any of these gears due to different bearing widths and gear teeth. The following chart shows how to determine which input gear you might have by transmission. It is always recommended to verify first hand if possible.

Because of differences in the cut of the gear, as a general rule, one should not interchange 1987-1993 gears with 1994-present gears. These years are not always hard and fast delineations. If one is not absolutely certain, disassembly and inspection is required.

Note that some transmissions change spline count. The Peugeot BA10/5 had both 21 or 23 splines. The AW4 had 21 splines through 1990. In 1991 (the same year the 4.0 HO was introduced) the AW4 splines increased to 23.

Be certain, in any interchange situation, that you select the right length of input gear for the factory style transmission being used; e.g., a long input gear against an AX15 (usually requiring a short input gear) will cause interference at the end of the splines and put damaging thrust pressures on the transmission mainshaft and transfer case input gear.

 

[Chris]

So according to that chart above, you have a 23 spline short input shaft.

That being said, look for a transfer case that came from a 1997-2002 Jeep Wrangler TJ. Make sure it has the short, 23 spline input shaft (which should be specified).

 

[Mike_H]

So according to that chart above, you have a 23 spline short input shaft (assuming you have an automatic transmission).

That being said, look for a transfer case that came from a 1997-2002 Jeep Wrangler TJ with an automatic transmission, that's it, simple as that.

I thought she said she has a manual? In 1999 that would be an AX-15 so it would be a short input shaft...

 

[Chris]

I thought she said she has a manual? In 1999 that would be an AX-15 so it would be a short input shaft...

I must have missed that. But the 32RH and AX-15 both use the same shaft. That chart above (and the info) was taken from Novak's website.