NP242 main shaft lock rings

[ehall]

I have recently noticed that sometimes the transfer case makes a grinding/rubbing noise, and other times doesn't. I replaced the chain a little while ago, and at that time I noticed that the main shaft was able to move back and forth a little and that there wasn't anything except the chain tension holding it in place.

Talking to one of the local mechanics that does a lot of 4WD mods, and although he doesn't know about the 242 he said the 231 likes to break a lock ring, and that some of the later models did not have a second lock ring at all. What's interesting here is that my 242 shows two grooves on the main shaft, apparently for each side of the oil pump housing bearing race. However this 242 only had the one lock ring on the outside of the race (to keep the shaft from moving inwards). The FSM also shows only one lock ring here.

Here is a vid showing that I can pull the main shaft backwards about 1/4 inch, and then the sprocket starts rubbing on the oil pickup tube.



Here is a picture of the shaft where the oil pickup housing would sit. There is a shoulder on the casting for the speedo gear cuts, and that stops the shaft from moving too far, but you can clearly see a groove right next to it. I am thinking that maybe I should put a lockring in that groove, and that will prevent the shaft from moving out as far.

What can you guys tell me about this? Should I look somewhere else? Is there supposed to be another lock ring somewhere that keeps the shaft from moving outwards?

Thanks

 

[Sidewinder CC]

There should be two (2) horseshoe snap rings there. Both are the same part number, J6134488. The one towards the rear output bearing will hold the shaft out, the other one holds the rear output shaft seal in.

Edit: Just reworked my 242. Those horseshoe snap rings are a PITA. You must have good horseshoe snap ring pliers to do the job correctly.

 

[ehall]

Thanks sidewinder, I am going to guess that you have the 96+ model since there are different setups for the output shaft seal, and the area in question is for both sides of the output bearing.

Anyway I figured I would experiment, so got that same part number from the catalog, and the dealer only wanted $3 each, but they are on back order (waiting production and not currently available). I bought some regular 1.25" snap rings from the hardware store even though they are slightly large diameter and thinner material, I figured they would be suitable for testing. With the stock lock-ring in the rear, the bearing race does not slide far enough back to expose the front groove fully. Even with the thin hardware-store snap-rings the groove was not exposed enough to use. So at least for me it seems that the inner groove cannot be used with the stock bearings.

I also looked at a bunch of pictures of transfer case main shafts on google images and could not find any that were clearly using snap rings on both grooves (the 231 and 242 seem to be the same here, btw).

Looking at the parts setup for a bit, the thing I finally noticed is that the whole bearing is moving back and forth along with the shaft. So putting an additional lock ring on the inner groove would not prevent the shaft from moving, since the bearing and lock rings would still move with it.

I remembered that the output flange has a groove in it for the race, so looked at that a bit, and noticed that the RTV I had used did not have an even smush pattern. So long story short, it seems the output flange was not installed flush, and was allowing the bearing race (and shaft) to move in and out too much. I reinstalled everything being careful to get it all even and square, and so far it seems to be working alright.

So final mark on this, it is the output cone/flange/whatever that prevents the shaft from moving outwards. The single lock-ring and the shoulder of the speedo gear casting are all that's needed to hold the output bearing in position

 

[OverlandZJ]

Hi Eric..

Both of my 242's (late 80's) had the snap ring on outside of the output bearing.. just pulled the tailcone off my 89 stock 242 to verify.

However, that snap ring is removed with the TW SYE i have on the other.. but uses a spacer to keep inward pressure on the bearing.

I dont think the tailcone is enough alone to hold the shaft/bearing assembly in.

Unless i misunderstood your post..

 

[ehall]

Both of my 242's (late 80's) had the snap ring on outside of the output bearing.. just pulled the tailcone off my 89 stock 242 to verify.

yeah but what is on the inner side of the bearing? there is a groove on the speedo gear shoulder and my original question was if there was a ring on that groove

although at this point I think it's moot, since (1) the race is too wide to use both grooves, and (2) the race moves back and forth with the shaft anyway

I dont think the tailcone is enough alone to hold the shaft/bearing assembly in.

well take a look at it, does it have a lip that the race fits into? if it holds the race in place, then it holds the shaft in place

 

[OverlandZJ]

I'll tear into it deeper and take a few pics for ya tomorrow bud...

 

[Sidewinder CC]

Overland,

Silly goose that I am, I didn't realize you have a .91 XJ (looked at your profile)...I thought everyone had a wonderful '99 XJ like me. :looney:

There are differences in these 242's, that's apparent. Looking at the Parts Catalog for the 91-93 it appears that only one retaining ring is called up for the '91, albeit, the same as the '99 ring. I've found lots of errors in the XJ catalogs, and FMS' for that matter, so I can't be positive that all you require is one ring. The '99 + or - rear output shaft uses three retaining rings; one to hold the outer race of the bearing in the housing (internal snap ring) that fits in a groove in the housing, one that holds the shaft to the inner race of the bearing (horseshoe snap ring) that fits in the bottom groove of the shaft, and one that is intended to hold the rear putput shaft seal in place (horseshoe snap ring) that fits in the outer groove of the shaft.

Looking at your shaft, it looks like only one snap ring is used. That would be the one that retains the shaft. I don't think yours uses a snap ring to retain the rear seal. Need a pic of your housing.

Here's a pic of my 242 shaft. note the two grooves.

Here's some pics of my 242 after I finished working on it.

 

[ehall]

final mark on this, it is the output cone/flange/whatever that prevents the shaft from moving outwards

I got my hands on a stock old-style tailcone and as you can see there is a recessed lip, which goes against the rear bearing, and prevents the bearing+shaft from moving backwards.

96+ uses a different design with multiple lock rings to hold the shaft in place