moby

if i engage 4part time or full time, I get a crazy sound from the front of the car.... a have a d30 in the front with lockright lockers. the sound is only therre when i give it gas and the car pulls to the left when driving in 4wd...

the sound is a mix of a thumping and whining.... and I only hear it if i engage the 4wd.... what could this be?

XJ?2010

sounds to me like it would be coming from the front axle or diff. maybe the T-case but thats in the center of the vehicle

moby

i was thinking front diff..... if the oil is low in therre would it make that sound?

moby

i checked the diff oil and its good..... all the u joints seem good as well, except the one from the tranfer case to the front axle, it seems a bit loose? is it supposed to be like that or could that be my problem?

moby

if anyone has any ideas what to check or troubleshoot please lemme know!

I wanted to head out and hit up some trails tommorow!

BlueXJ

moby do you have a vacuum disconnect D30. Sounds like the disconnect on the passenger side. there is a shift fork and they get sticky and hard for the vacuum motor to move so it may be halfway in and halfway out. Worth checking.

moby

I have the d30 without vac!

im thinking maybe an axle is bent very slightly? or something in the diff is really broken? when its in 4wd it squeeks and the front wheels are getting power but its like something is forcing that shouldnt be... making the awfull sound!

moby

after reading a bunch im pretty sure the sound is a u joint.... either from the tc to the front axle or drivers side wheel.

what is the best way to check a ujoint?

I know they have been replaced at least once since they are the greasable version....

If i need to replace, can I do it myself with basic tools?

Thanks!

BlueXJ

You will need a vice or a press to get them out and back in. I have seen it done on the trail with a C clamp. We are talking about axle u-joints here. The driveshaft is much easier but will still need to press in one side with the same tools vice, press or C-clamp. There may be other suggestions on methods to change them but I have never seen any.

whowey

Blue... how about suggesting he look at the tech section here. I'm fairly sure there is a write-up there about changing them.....

Moby, If your axle was bent you would hear the noise all the time. Because you have the NP 242(full-time), the front axle shafts spin all the time. So does the front drive shaft. The 242 uses a center axle disconnect style of engaging the 4wd. The clunking sound you describe certainly sounds like a U-joint gone bad. When you have no power being delivered to the front, the shafts spin but make no noises. When you add the power, then the clunking appears.

moby

exactly!

thanks for the info guys, I will be checking out the technical section for some more info about changing ujoints.....

BlueXJ

Should have thought of that but I was half asleep. Thanks whowey.

moby

well after changing ujoints on the front driveshaft the sound is still there!! maybe its the ujoints on the axle to the wheels? before I change them, how can I check to see if they are bad first?

88pioneer

my friend had the same problem on his jeep with the 242. i watched underneath and thought it maybe the pinion on the axle. but then under closer inspection found that the exhaust pipe bracket was broken and the pipe was rubbing the driveshaft. just a thought on something else to check

TrueBlueXJ

Check them for play. Get on the ground and grab ahold of the yoke and SHAKE! If there's any play or clunking, the u-joint's shot. Changing them out isn't bad, takes about 2 hours. If you don't have a vice or a big C-clamp, you can use a large socket and a hammer to pound one side of the u-joint out, forcing the other side into the socket. Works just as well, just watch your fingas.

And the easiest way to remove your wheel hub: put a stubby 3/8" drive extension between the hub and the yoke on the axle shaft. Turn the wheels to the left, insert extension, turn the wheels to the right, and listen for the pop. Then pull the shafts and get to work.