Transfercase Noise WIth Front Shaft In.

Im having this rolling/grinding/clicking type noise coming from under the jeep most noticeable when in the jeep windows up. At first i thought it was the front axle but its completely silent. I can drive around with my front drive shaft out and there is no noise what so ever. Soon as i put the front drive shaft in the noise is back, regardless if im accelerating or decelerating, seems to make noise as long as that front shaft turns.

So if its not the front axle, my driveshaft was checked out and its fine, fluid level is fine, then it has to be something with the front axle side of my transfercase, its definitely not coming from the rear driveshaft side. I know nothing about working on transfercases so i just assume its a bearing of some sort that is bad and makes noise when there is a little bit of drag on it? I have done a SYE to my transfercase before and thats the most ive done on them, which was fairly easy and that doesnt change anything with the front side of transfercase either so i dont think something got messed up during that. I did notice the front driveshaft side tcase yoke seal has a little bit of fluid leaking out and down the tcase.

If anyone has any ideas what i should do next or what it could be that would help a lot, whether if there is a bearing that could be the culprit and could be replaced or if i most likely need another transfercase or something, thanks.

There are two bearings in the transfer case for the front driveshaft. One is a set of needle type bearings in the rear half of the case and the other is in the front half of the case. Do you feel any roughness if you turn the front transfer case yolk? There is a gear sprocket and a chain that connects it to the main shaft. The front bearing and seal are easy to change. The rear requires a special type of puller, but you can get it at HF or rent it at some parts stores. Personally I'd lean towards thinking its the front driveshaft and the test method was faulty, but the front seal should be changed regardless.

So the two bearings are #27 #26 that you are talking about? Ill have to pull the front shaft and see what it feels like. You lean towards thinking its the front driveshaft making the noise not the transfercase is that what your saying? The joints are tight, bolts are good and i even re greased the driveshaft, what else on it would make noise like that? thanks

http://www.jeep4x4center.com/jeep-transfer-case/np-231-parts.htm

Morris isn't always correct in their cross references. I think the bearings are 12 and 14.

I can tell you with 100% certainty that if its a NP242 you'd use SKF or NSK 6207 and Timken 341022 for the front output seal and bearing. I don't think there's a part change with a NP 231 but there may be. I just put these in my NP 242 last week when I put in the SYE. I got the Timken seal because NAPA didn't have the SKF seal in stock and Auto Zone is a block away.

I think the driveshaft is more likely to give you grief than the bearings, but you never know until you test. There is likely going to be some slop in the bearings. Even new will have it. Feel for roughness when turning the yolk.

If you decide to do the bearing and seal, you can get a pair of Sears Craftmans lock ring pliers for about $16 to get the bearing lock ring out (its a snap ring without holes). Then you can just tap the bearing out with a punch from the seal side. And once that's out you can tap the seal out with a screwdriver or punch. Installation is the opposite.

The yolk nut is 28 mm. The whole case is metric.

The driveshaft has a ball and receiver in that double cardan and it can run dry and wear with time and use, plus the three 1310 u-joints. it may be in that double cardan that you have problems. google "jeep angry sparrows" and see if its anything like that.

Alright the noise isnt anything like the angry sparrows, this noise doesnt squeak or squawk at all like that its a rolling grinding clicking noise, you hear it most at like 1st and 2nd gear speeds but i dont think the noise gos away in the higher gears you just dont notice it as much. I guess ill remove front shaft and try to see what the yoke feels like turning it. The u joints on the shaft seem fine but im not sure about the double cardan part of it, cant imagine it making noise like that and doesnt seem like i could tell if its bad without taking it apart either.

Alright so pulled shaft again and while it's a little worn it's smooth and joints are tight. That front yoke though while spinning has a little noise to it. Not really bad and it spins freely but not smooth, I'm not sure how smooth it's supposed to be though.

Here a video

Have you had the transfer case open before, like when you did the SYE?

It looks like that dust shield is out too far. On my 97 its right up near the case. Could it be that your yolk nut is loose and its backed off? The chain is going to make some noise when you're turning it.

At this point I'd probably drain the fluid, note any obvious metal, and then look up in the drain hole and see if the chain has a lot of slop in it. Then split the case open and take a look.

You can probably fix this for less money than a JY transfer case, unless you JY has some really good deals. May just need that one bearing and seal.

Yea its been split to do the SYE, ill have to check and see if that yoke is seated all the way, ill see what that nut is supposed to be torqued at also.

That would be ridiculous if its something that simple but who knows, would probably explain the oil leaking also if so. Yea it was hard for me to tell if that noise while spinning was normal or not because i knew some of the noise was oil sloshing around and the chain and stuff spinning around.

If i cant figure anything out from that i guess ill split it open and see...id hate for this to give me problems during the winter better get it done now.

Torque is 90-130 ft lbs

You can also smear some RTV on the splines to try and keep the oil from coming out. There's also a rubber washer that goes at the end of the shaft under the nut.

Alright thanks, we'll see what happens.

x2.. that front yoke is out way too far.

Well drained fluid and removed yoke, fluid was clean besides a very fine silver film in it pretty hard to see. Thinking it might be from the case. The yoke was seated all the way believe it or not cleaned everything up and torqued it down to spec filled with fluid and still does same thing. The noise doesn't really appear till the tcase gets warmed up it seems after first few minutes you'll begin to hear it. The noise is at its strongest around 20-40 mph. Really leaning towards it being the tcase chain now being stretched and rubbing on the case not sure what else would do it besides that. When in 4wd it's a decent bit quieter probably since the chain slack is pulled tight. Let me know if this sounds right and what else to check at this point I'm probably gonna split the case and take a look for anything obvious then change the chain I suppose. Thanks

Seated all the way

Tighten down all the way

Same as before

You ought to be able to see the chain from the drain hole. With the back of the case off, the main shaft will rotate down and left and make it look like the chain has extra slack. The other way to compare chain length is side by side against a new chain. I'd imagine you can go down to the parts store with your old one put it next to a new one. It could also be one of the bearings. When you pull on the REAR output does the main shaft move up and down? On my case before I opened it, there was slop in the bearing seating in the housing. With the SYE, when I tug on the rear output the engine case moves on the mount. If there a silver film its probably aluminum from the case because the magnet should catch iron from bearings and the chain unless you don't have a magnet. You might look closely at the oil pump and oil pump seal when you take it apart. For whatever reason, my oil pump seal was rock hard and I'm not sure I found all the seal material. I'd also try to find out why that oil slinger does not seat closer to the housing. Before spending any money on parts I'd take a good look at everything and consider a JY case depending on what is found.

I realized there is an error in one of my previous posts, the Timken seal P/N is the oil pump seal, not the output flange seal.

Alright yea i guess ill have to just take it apart and see what i find, if the bearings are good i guess its the chain, ill try to find rub marks. Now that i think about it being a chain seems pretty possible because the sound it makes does seem like a chain rubbing over something type of noise.

No i havent tryed pulling on output shaft to see if the main moves, as for the yoke im really not sure but you can see the bearing lands/ seal surface on the yoke. If it was in any further the seal would ride against the rusty surface of the yoke so im thinking its normal i guess.

I know a transfercase is usually pretty cheap but id much rather fix what ive got unless mine is somehow ruined, swapping a chain out shouldnt be hard at all, or a bearing. But swapping the whole case and moving my sye parts over to it and making sure the chain and bearings and whatnot in another case is ok just sounds like a pain. I guess i dont have anything to go by with the chain being stretched or not i could try to take some pictures of it and maybe take it into a store that has a new one to compare. Thanks

So everything is apart and cleaned up, all the bearings are fine i checked them and had my dad give a look too and they are all smooth. One thing i did see was the plastic pieces on the smaller shift fork were worn down to the metal and alot of that plastic from it was embedded in the oil pickup tubes screen, so i ordered a new shift fork for it but everything else seemed fine not sure what else to do but put it all back together with the new shift fork and see what happens.

The chain seems to be fine also, doesnt look stretched to me. I also dont think anything got put on backwards when i did the sye but i could be wrong i suppose, im wondering if i got the mode ring or whatever its called in the last pic on backwards. I dont know why the shift fork got that way, whether its normal wear and tear or if something else is messed up. Unless anyone has any other input at this point ill put it back together with new fork and see what happens if i get noise i guess im looking for another t case.



pushings shaft up

One last bump for input or help, otherwise tomorrow im putting it all back together with new shift fork and hoping for the best.

Nothing looks terribly bad except for the shift fork. Could the linkage could have been slightly out of adjustment causing the gear to be attempting to engage slightly? That could explain a rattle sound when the front DS is in.

It is pretty difficult to check chain stretch when the back half isn't on. Really you need to look through the drain or fill plug.

What I would do is replace the shift fork and bushings. Put it back together. Disconnect the shift linkage from the transfer case, and make sure the transfer case is in 2wd. Then drive and see if the clicking sound is gone.

You can see in the one pic i push up on shaft it doesnt look like the chain is bad at all. I also was wondering about the linkage being off, it engages fine through everything though. Ill have to look into it ive never messed with one.

Yes, I see you pushed the shaft. Just because you pushed it doesn't mean it is where it is when assembled. The shaft will hang under gravity with the support of the rear bearing. That means that there is enough play to move way out of position to where it should be when installed. There is also no support on the front shaft.

I keep going back to that front yoke and why it sticks out so far. Missing the lock ring in front of the bearing?

Well im going by pictures ive seen of chains stretched and mine doesnt look that way, plus there is no gashes in the case. There is multiple variations of the np 231 ive seen a few pictures of ones that looked like mine and had the yoke sticking way out.

I dont see how it would go in further it gos in as far as the bearing lands show, if it went in further it wouldnt be riding on the lands and tear the seal to hell at least. You talking about the snap ring basically between the bearing and case? Pretty sure that is there, wouldnt change how the yoke sat out much as it does anyways.