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87xjco · 11-21-2008, 06:53 AM

I didn't see a SYE write up here. I did one a few years ago that I took alot of pics on

NP231 transfer case out of a 1987 XJ

Remove 1 1/8" nut and tap off front output yoke, the instructions say to put the transfer case into 4low and remove the shifter lever. I did not remove the lever and had no problem.

Remove the speedo gear housing and note the position that it was installed in.

Remove the 3 15mm bolts around the rear output slip yoke housing.

Remove the snap ring next to the bearing

A gasket scraper can help split this housing from the rear case half. Be carefull to not gouge the rear case half surface.

After housing removed you see the oil pump and shift fork shaft

Remove the bolts around the transfer case so you can split the two halves of the case. There is this 12point 10mm bolt and two 15mm bolts with washers on them, note the location of these. The rest of the bolts are all 15mm with no washers.

There are 2 slots like this that if you carefully drive a large flat screw driver into, will split the case without damageing the gasket surfaces.

After case is split

Wiggle out the front output shaft and remove chain and set aside

Wiggle out the main shaft and set aside

Two gears and a sincro stay on the shaft as it is removed

87xjco · 11-21-2008, 06:54 AM

You will need to transfer the two gears and sincro onto the new mainshaft

Some older model transfers like mine have caged bearings that need to be discarded, use a brass punch and set the gear on a wooden block to avoid damage as you drive them out.

After the caged bearings are removed, clean and pre-lube gears

Supplied snap rings and hardware, the two matching rings are for the speedo gear and the other is the gear snap ring.

Install gears and put on the new snap ring supplied.

If you set the case flat it is easy to first wiggle the main shaft in thru the sincro shift collar and into the splines at the front of the case. Then install front output shaft and chain together, wiggle and turn the shaft to get it to slide in.
Then install a thin layer of silicone.

The rear case half installs by sliding over the main shaft and making sure the splines for the oil pump do not bind up. Once in place make sure the oil pump tube is still seated in the oil pump at the bottom of the transfer case

First put on the forward snap ring and then slide on the speedo gear and then install the rear snap ring

Instructions say to cut the shift shaft shorter. It needs to be the right length if you need the vacuum switch to operate properly.

The depth measurement I came up with is 15/16", 1" is just a bit too long for the housing to seat against the rear case half.

Transfered that measurement to the shaft

Then wrapped the transfer case with plastic and cut the shaft off with a cut-off wheel. Hacksaw or dremmel tool can also be used.

Polished the end of the shaft and then pulled off the plastic & put a thin layer of silicone on.

Installed the speedo gear housing in the same position as when removed, bolted on the housing and torqued to spec, then slid on the yoke, rubber washed and lock nut and torqued to spec.

**muddeprived** · 11-21-2008, 07:24 AM

very nice write-up. Much needed for those guys lookin to install it. I dunno how you work with those gloves on man. I'm a bare-hand man, gloves get in my way.

87xjco · 11-21-2008, 07:45 AM

Quote:

Originally Posted by muddeprived

very nice write-up. Much needed for those guys lookin to install it. I dunno how you work with those gloves on man. I'm a bare-hand man, gloves get in my way.

Yeah once they come off, they tend to stay off