TheDesertlights

Alright guys went offroading yesterday,used 4 hi, when I was done I went back to 2wd. Noticed some whirling sounds when I got back on the road. This morning trying to figure out whats wrong I check the rear diff and its fine. But I turned over the xj and went into 4 high no problem. Put the T-case and transmission in neutral and then tried to put the transmission is reverse or drive, grinding occurred. Next I shut off the engine and shifted back up to 2hi and into park. Okay lets try this again, turn on xj, put transmission in neutral, put tcase in neutral works, try to go into 4 lo, grinding occurred. Try to go back to neutral grinding occurs. Turn off XJ shift to 2 hi, turn xj back on run transmission through all the gears, and its fine in 2 hi.

So what the hell is going on? Am I doing something wrong or is my tcase fubar'd?

Fred/N0AZZ

Make sure the linkage is adjusted properly and in good shape.

ehall

The transmission will grind if the transfer case is in Neutral

TheDesertlights

Figures, I just wasnt sure. I thought maybe I could put the tcase in neutral and send power to it and see if there was a problem inside the tcase.

Anyhow just went and picked up a hex 10mm and pour almost an entire quart of atf in it. I hope that solves my problem.

AceWhite

NP231 transfer case- fulltime 4WD
You need to be rolling for a smooth shift FYI

TheDesertlights

Yeah figured that out a while back. Also did some rebuilds for a friend on his np231 and well got real friendly with how everything works. Although I have grown to hate all snaprings.

cruiser54

How's the transfer case fluid level and condition?

And, here's how to shift it.

Here's how the factory suggests you shift the transfer case and I've been doing this since these things were new and I worked at the dealership. Quoted from the owner's manual. The suggestions in CAPS are mine.

"To engage, shift the transfer case lever from 2H to 4H while the vehicle is moving at any legal speed". I LET OFF THE GAS, THROW THE LEVER, TAP THE GAS AND LET OFF.

4L position: " To engage, slow the vehicle to 2-3 MPH , shift the transmission to Neutral, then shift the transfer lever to the right and pull firmly rearward to 4L".

TO SHIFT OUT OF 4L, SHIFT THE TRANSMISSION INTO NEUTRAL WITH THE VEHICLE STOPPED, SHIFT THE TRANSFER CASE LEVER TO 2H, THEN THE TRANS TO D IF YOU HAVE AN AUTOMATIC, OR INTO FIRST GEAR WITH A MANUAL, AND CONTINUE ON.

Revised 11/20/2014

cruiser54

Correct about the rolling, but the NP242 is full time and NP231 is part time.

Fred/N0AZZ

Best $40 addition I have made to my NP-231 was install the Boostwerks TC Shift linkage. What should have been from the factory.

Jeepin'_Aint_EZ

I want to get this linkage. Looks beefy! Don't have to worry about yankin on the ol 4 dubya D stick and feeling the linkage bend or not want to cooperate!

But ever since I adjusted my factory linkage, it's been buttery smooth for shifts.