Something blew up

[jimbrown]

Hope everyone in the NE is doing well after that storm.

Anywho, I had her in 4HI drivin down the highway after the storm when something in the KJ blew up or popped or snapped. The loud noise startled me and I prayed that it was not the motor or ******. Immediately shifted the T case back to N. Popped the hood took a quick look and drove it home and it actually seemed to drive normal. Checked Trans fluid and engine oili and they look good.

It makes a strange noise now only while the vehicle is in motion and not when the motor is idling with vehicle stopped so i am confident its not the motor.

Are the T cases chain driven or gear driven? It sounds like it could be a loose chain that snapped. Idk..

I know the sound can be anything but I was wondering if anyone is familiar with it. Anyway, here is the video. The sound is audible over the wind. Sorry for the view of the road.

https://vimeo.com/59427854

 

[1BADKJ]

Chain. Sounds like a CV joint

 

[hectikart]

x2.
Front Driveshaft CV is notorious for causing 4wd problems. Were the roads just wet or still snow covered? Could have bound things up if you had too much traction.

 

[jimbrown]

Yeah I agree, sound is coming from the front end and ur explanation makes sense. Nah...It was a major parkway and the day after so it was actually dry if i remeber correctly. In hindsight I should have realized the major parkway would have been dry as the side roads were still wet and icy/slushy and taken it out of 4hi.

(assuming it is front CV which it probably is) Is it dangerous to drive on or could it just cause further damage to vehicle like the axle, wheel etc? I have already drove around 20 miles with it.

I have absolutely no experience with axles and CV joints. Normally do you just replace the bad joint or the entire axle halfshaft? I guess it depends on damage?

 

[hectikart]

If it is the driveshaft CV it should be fine, just done use 4wd. You can actually completely remove the front driveshaft and still drive around no problem as long as you keep it in 2wd. First thing to do would be to check the boot on the CV joint for tears, see if there's any grease around it. That's a giveaway that it needs to be replaced. If you need to do the CV axle, you should plan on doing the intermediate shaft as well. They're usually rusted together and come out in one piece.

Here's a good How To on the front driveshaft. It's very easy to replace the head:
http://www.jeepkj.com/forum/f202/how-change-front-driveshaft-change-driveshaft-head-47161/

I would definitely check the T-case though too...Driving on dry pavement in 4hi or 4lo (unless you have full-time 4wd) is what will cause driveline binding and can potentially wreck your t-case, differential, etc. Open the t-case fill hole and stick your finger in. You should be able to feel the chain, and it should have tension. Do you still have 4wd?

 

[hectikart]

also, does the noise get faster/slower according to your speed or is it constant? If it's changing according to your speed it might even be a bad u-joint. That's something to take care of ASAP, don't want to drop your driveshaft on the highway.

 

[jimbrown]

Thanks for that article and input. Great point, I forgot to mention that in my OP...Yes, as the vehicle slows down so does the the sound.

 

[TwoBobsKJ]

If you have the part time Command Trac transfer case and you drove down a wet highway in 4HI it's likely the transfer case is destroyed.

If it was one of the CV's - whether the driveshaft or the front axles - you would hear more of a click. The sound in the video reminds me of a chain on my old banana bike hitting the chain guard. I'd guess the chain in the transfer case broke.

Bob

 

[jimbrown]

Well, I found the problem.

ImageShack® - Online Photo and Video Hosting

ImageShack® - Online Photo and Video Hosting

The images are of the prop shaft that drives the front axle on the end that closest to the T-case. I assume there was once a boot there? Notice the loose piece of metal sitting on the shaft... Not sure what that is..some kind of bearing or seal or just a shredded piece of shaft?

I guess I need to replace the entire driveshaft?

Thanks for your help

 

[tommudd]

Well, I found the problem.

ImageShack® - Online Photo and Video Hosting

ImageShack® - Online Photo and Video Hosting

The images are of the prop shaft that drives the front axle on the end that closest to the T-case. I assume there was once a boot there? Notice the loose piece of metal sitting on the shaft... Not sure what that is..some kind of bearing or seal or just a shredded piece of shaft?

I guess I need to replace the entire driveshaft?

Thanks for your help

Can be rebuilt for 65-70 bucks
Search............

 

[jimbrown]

Thanks. Ill keep that in mind. Can someone tell me if there was once a boot on the end there and what that piece of metal causing the noise could be?

 

[tommudd]

Thanks. Ill keep that in mind. Can someone tell me if there was once a boot on the end there and what that piece of metal causing the noise could be?

Yes there is suppose to be a boot there, no boot, dirt, crap, mud gets in there and bearings fail, and then need replaced
easy fix

 

[hectikart]

Yes...the notorious front driveshaft CV I was talking about earlier....Posted the "how to" link in a previous post.

 

[jimbrown]

Yes...the notorious front driveshaft CV I was talking about earlier....Posted the "how to" link in a previous post.

Right, thanks. You were dead on with that.

Shouldn't be a problem to drive as long as its in 2WD right? Of course more dirt and crap will accrue in the bearings but they need replacement already....

Not to be a pest but can you explain the driveline bind regarding the 4WD with adequate traction? I was driving straight down the highway when it blew if i recall.

I am sure it has to do with the part time setup and no center diff between rear and front wheels. Im pretty sure both diffs are open. I know that when you turn this means the back wheels will slip cause front and rear wheels are essentially locked together. Idont understand why it blew up while driving straight down the parkway.

 

[tommudd]

Just remember everything still turns no matter if its in 2 wheel drive or not. Soooo the front driveshaft is spinning .........

 

[tommudd]

Just remember everything still turns no matter if its in 2 wheel drive or not. Soooo the front driveshaft is spinning .........

Its bad to drive like that due to different rotational speeds
due to gearing/tires etc

 

[JeepCoMJ]

you need to pull the front driveshaft if you are to keep driving it.

you already did one oops by driving in 4x4 on dry or patchy pavement....part time 4x4 is ONLY for loose terrain. you're damn lucky if that is the only damage you did. I've got several np231s sitting around from parts jeeps that are split in half because of this.

that driveshaft gave out due to binding on pavement, not to being week. there was a boot there, but it looks like it's been gone awhile, and whatever was left was thrown off when it was destroyed.

Leaving it on and driving it is asking to have it lock up, and cause binding elsewhere and causing more damage.

 

[TwoBobsKJ]

...I am sure it has to do with the part time setup and no center diff between rear and front wheels. Im pretty sure both diffs are open. I know that when you turn this means the back wheels will slip cause front and rear wheels are essentially locked together. Idont understand why it blew up while driving straight down the parkway.

You may have been driving straight at the time but at some point you were turning and that got the drive line out of sync - that starts the binding.

Remember, when turning each of the four wheels runs in a separate arc - each wheel travels a different distance. That's why you can only run a Command Trac on slippery surfaces so the tires can slip and avoid binding.

Replace that CV (please, DON'T listen to somebody who says the only cure is to replace the entire driveshaft!) and you should be good to go. Your T-case chain may be stretched but hopefully not so badly that it's not driveable.

Here's the link to the part - just $55 plus shipping.

Bob