CB900SS

Hello, new to the forum and hoping you all can help. My jeep is a 1995 full time 4x4 with a 4.0L;


I'm looking for an NP-231 transfer case to swap into my Jeep, as you guess my VC is shot. I drive the truck on the beach constantly and need to fix it. Even though its great on the beach, I know if I put a 249 back in it would suck (because it wouldn't be locked into 4x4).

So my concern is this. This is also my daily driver, I'd hate to get a NP-231 and have the wrong input shaft with the wrong gear cut. So should I pull my case, measure and count and put it back in to drive while I get the right case with the right input shaft?

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Also my second issue is a complicated one, and it comes and goes. The truck is bucking at higher RPM (like while passing), like getting fuel, then not getting fuel... Throttle on and off. So the truck bucks. But it only does this about say 3,000 rpm when its not so bad... At times it can do it at lower RPM. Also a few times the truck has bogged totally down and wouldn't rev past idle at all, but didn't stall. Shut it down and re-start and it revs up OK.

The fuel filter has been changed multiple times (all looks clean), added in fuel tank driers. No codes ($2k Snap on scanner used), fresh full tune-up. We hooked a fuel pressure gauge to it last night and drove it (routed into the truck through the window), all of a sudden the truck drove fine. The fuel pressure was around 50psi and would go down to about 30psi under a heavy load. Disconnect the gauge, let the truck sit, went home later... The truck is "bucking" again. I'm a pretty good mechanic, my uncle is really good... Were both stumped at this point.

Also, the truck is shifting down fine and not getting stuck in overdrive or lockup.

Sorry for the long post, I hope someone can follow it and steer me in the right direction.

CB900SS

Running is fixed, new fuel filter. I took the fuel filter off and the fuel coming from it was nasty. I turned the key on and off and caught some fuel in a clean container coming from the tank. Looks clean, but it was above a quarter tank of fuel. I have a habit of running my truck to low on fuel and probably sucked some crap that clogged the filter again. I will have to keep it above a quarter tank from now on.

Lets get back to this transfer case... Can anyone suggest what case to buy? Or just pull my case first and measure?

Is the serial number on the case tag the build date?

Also I just replace my rear pinion seal, back there messing with the filter I noticed its leaking again. I guess try another seal? I need to do an axle bearing and a seal on the right rear also. Does it ever end?

OverlandZJ

No it never ends...

Sounds like you'v done some homework on this as your familiar with the gearcut change in 95.

The ZJ has a longer input than say the XJ and YJ/TJ, thats where the swap can get tricky. If you get a 231 from a ZJ it "should" be a direct bolt in. I also think you may be able to use your front case half and input gear assembly with a 231 (or 242) internals as well if you get a pre 95 231 donor case.

There are a few lengthy threads at www.jeepforum.com and www.nagca.com that you may find usefull.

I'm not sure about the WJ's compatability..

CB900SS

Thanks for the reply, I'll look for a ZJ case then.

I guess it really never ends. The truck is running out of fuel again... I cut open the old filter and its spotless. But the fuel that ran from it seemed very dirty to me. I ran the pump and sampled fuel from the tank, looked spotless.

Do I pull the tank and really see what it looks like in there? How does the sending unit pull fuel? A sock?

CB900SS

I need some help here folks!

My jeep is still bucking when you give it more than a 1/4 throttle at times. I believe it to be fuel cutting on and off... With the fuel pressure gauge hooked up and giving it a lot of throttle (driving) it drops to 20psi. Idling its at 48psi.

My old fuel filter looked really clean. I squirted a bunch of fuel through the gauge and it looks very clean.

What ohm reading should I get from the TPS?

I want to get this fixed so I can move onto my transfer case.

OverlandZJ

PM'd you..

CB900SS

I'm still stumped here.

My uncle is going to see if he can borrow a fuel pump/sending unit tomorrow.

CB900SS

Alright, I wouldn't have had a fuel pump to test with until Monday. So I pulled my fuel tank and opened up the bottom of the sending unit. What a shock, the sock was almost totally clogged. I cleaned it up good and checked the tank and it was surprisingly clean. So I put the sock on and put the tank back it. The truck seems fine for now, but I don't like it and want to put a pump in. The current pump has 190,xxx on it and I'm sure will leave me stranded.

What fuel pumps can someone recommend? I don't want to buy one of those cheap ebay pumps and have it leave me stranded two months down the road.

I see some nice trucks on this forum... I was expecting a little more activity.