Topic: knocking sound coming from front end

[stan98tj]

need some help once again people.
a few days ago i noticed a knocking sound coming from somewhere on the front end. i have it narrowed down (i think) to the front driveshaft or related mechanisms. when i drive i get a metal on metal clicking sound. does not do this at idle or in reverse. i shifted into 4hi and the noise got worse AND you could feel every knock-4lo was same deal only deeper and harder. shifting out of 4hi to 2wd carried the noise and vibration for a little bit then i felt almost a "release" and the noise backed off to the "lighter" knocking it makes in 2wd. if this at all makes sense.

my front drive shaft rotates in 2wd...is it supposed to?? i figured it shouldnt until i engage the 4wd. i may be wrong. in neutral on both t-case and transmission selector my front drive shaft should rotate freely by hand...but it doesnt.  there is not actual "play" in the front driveshaft...but it will rotate up and down about half and inch or less. i compared this to the rear which doesnt budge. but the front driveshaft doesnt shake side to side or anything. i just went out to reconfirm this while writing this post but the vehicle is in park so i dont know if that makes a difference..but that driveshaft just rotates half inch or less right to left.

ive read about a motor and vaccum line that engages and disengages the hubs..i dont know how labor intensive it would be to change that or how to check to see if it is shot or not. dunno if its the t-case, or the U joints...im pretty much over my head on this one.
any help would be appreciated.

- stan

[chkustom]

It sounds like your problem is in the front driveshaft u-joints. You don't have any form of disconnect in the front axle which will cause your front shaft to always turn. I assume that you have a tj from your profile with a dana 30 front axle; if so you dont have a disconnect. To confirm the drive shaft joints are at fault remove the front shaft and see if the problem goes away

[sharpxmen]

if you don't have any lockers you could lift one side of the Jeep, stick it in 4wd + first gear and listen, the side that is lifted should have the wheels spinning, make sure you don't have the e-brake on and the side that is on the ground has the wheels secured. Jackstands under the axles on the side that is lifted works best as it will also prevent the Jeep from rolling but even with those you should secure the wheels on the ground as well. Could be like he ^ said the d/s but also the axle u-joints, t-case or the R&P or spider gears on the diff. Once you have it lifted and spinning would be easy to pinpoint. My guess is the diff (R&P or spider gears) based on what you describe, butcould be something else as well, these are the few i can think about.

[stan98tj]

i put in a rough country 2.5" lift a year ago that came with a t-case drop kit. i didnt put it in cause i figured no vibration, no problem. iknow, STUPID, STUPID!!  now that i think about it, i prob should have put that kit in..if that is one of the reasons im having these issues then my problem can be localized to my drive shaft u joints and no further right? any chances i could have a crapped out t-case...im hopin not cause i figure thats the most expensive of all the probable issues.

[sharpxmen]

you don't need a t-case drop with 2.5'' lift - i only did that when i added another inch with the shackles. it worked with no probs w/o the t-case drop and the 2.5'' lift for 2 years or so. I don't think that's the problem.

[stan98tj]

if the u joints were shot, a wobbly driveshaft would indicate this?? mine doesnt have any play in it except it can be turned by hand a half inch up or down...so maybe i can rule out u joints. i figured with the lift and no t-case drop that i prob put on some extra tension on the d-shaft since it would have not been at a stock angle..even if the lift was only 2.5" Im now worried this could be a more complicated issue. im gonna have to get her into the shop tomorrow as im out of time (got my 3rd mate's tests in a week!!) kinda wanted to have a few ideas to throw around to the mechanics when i bring her over..so as to avoid costly unrelated repairs and such.

[aw12345]

Stan, simply take the drive shaft out, drive it problem gone check the cv joint as well as the U joints for roughness, stiffness and play. Then replace as necessary

[stan98tj]

thanks art. ill have the mechanics focus their attention to the driveshaft and hope for low repair costs..lack of time right now is keepin me from messing with it on my own...im gonna need it back on the road asap..its one of those problems that couldnt have picked a worse time to happen lol.

[aw12345]

Tou can drive it just fine without the drive shaft so for that matter take those 8 bolts out and you are on the road to happiness

[jagular7]

If you are going to pay a shop to look and work on your situation, then have them diagnose the problem and give you an estimate before performing any work. They will probably also show you the problem. Without specifically looking at it and telling you what the problem may be without you knowing what to look for, this introduces other problems.

Adding a lift and not putting everything in that the lift provides shouldn't be a big problem, depending on the item not installed. Not installing the drop spacers for the crossmember should have introduce vibrations from the rear ds. The front shouldn't be a problem. I would seek a local 4wd club to participate as a member. This will help you learn about the mechanicals of your Jeep as well as have you learn to work on it. Plus there will be comraderie and fun on the trails.

[stan98tj]

well i knew enough of the basics to have em focus their attention on the areas i thought were generating the problem. my issue is that unlike many of the members here im not all that jeep/mechanically savy yet. it's a learning process i suppose...how many ppl can you think of that go from knowing near nothing about cars, to purchasing a car and 4 days later are forced to figure/learn how to put in a new motor??!! lol it's been a baptism by fire with this jeep.  i read the forum every day and i appreciate all the help from you guys who know your way around the 4 banger. i used what i know and the responses to this thread to pretty much give the mechanics as much as i could information wise...now im gonna sit and wait for the call. 
by the way, the head guy there said just from description it could be the ring at the leading edge on the front end..they're pretty thin and usually go...just wanted to let you guys know..see what you may think.
-stan

[sharpxmen]

well i knew enough of the basics to have em focus their attention on the areas i thought were generating the problem. my issue is that unlike many of the members here im not all that jeep/mechanically savy yet. it's a learning process i suppose...how many ppl can you think of that go from knowing near nothing about cars, to purchasing a car and 4 days later are forced to figure/learn how to put in a new motor??!! lol it's been a baptism by fire with this jeep.  i read the forum every day and i appreciate all the help from you guys who know your way around the 4 banger. i used what i know and the responses to this thread to pretty much give the mechanics as much as i could information wise...now im gonna sit and wait for the call. 
by the way, the head guy there said just from description it could be the ring at the leading edge on the front end..they're pretty thin and usually go...just wanted to let you guys know..see what you may think.
-stan

if by the ring he meant the ring & pinion that was my guess too based on what you describe - did they lift it and put it in 4wd - if yes, they can actually listen to find out exactly where the noise is coming from; you can do that too with a long screwdriver by sticking the metal on a part (that is not rotating of course) and put your ear on the handle - you'd be surprised how clear is the sound.

[jagular7]

well i knew enough of the basics to have em focus their attention on the areas i thought were generating the problem. my issue is that unlike many of the members here im not all that jeep/mechanically savy yet. it's a learning process i suppose...how many ppl can you think of that go from knowing near nothing about cars, to purchasing a car and 4 days later are forced to figure/learn how to put in a new motor??!! lol it's been a baptism by fire with this jeep.  i read the forum every day and i appreciate all the help from you guys who know your way around the 4 banger. i used what i know and the responses to this thread to pretty much give the mechanics as much as i could information wise...now im gonna sit and wait for the call. 
by the way, the head guy there said just from description it could be the ring at the leading edge on the front end..they're pretty thin and usually go...just wanted to let you guys know..see what you may think.
-stan

Understood. Not many people like to get their hands dirty either when they buy. I've been a motorhead since I can remember getting subscriptions for CarCraft, Hotrod, etc back in the mid 70s', about 10 yrs old. Damn, I'm old....
Like I said, they should point out the problem, give you some options to consider, and estimates for the options. Using your knowledge and mechanical understandings, then you can decide to perform the work yourself, with a buddy or members of a club, have the garage do it, or whatever. Since it may be a clunker..... ..... nevermind.

[stan98tj]

Understood. Not many people like to get their hands dirty either when they buy. I've been a motorhead since I can remember getting subscriptions for CarCraft, Hotrod, etc back in the mid 70s', about 10 yrs old. Damn, I'm old....
Like I said, they should point out the problem, give you some options to consider, and estimates for the options. Using your knowledge and mechanical understandings, then you can decide to perform the work yourself, with a buddy or members of a club, have the garage do it, or whatever. Since it may be a clunker..... ..... nevermind.

given more time and no pending license tests i would have waited and had some of my friends look at it, picked a free weekend and would have broken out the tools like i did with the other few "quirks" it had. this time im kind of against the wall-ill have the shop tell me whats wrong and give me a quote and go from there.

[stan98tj]

drive shaft is shot...i know Art, i coulda pulled it out like you had said lol-time wasnt on my side this time. anyway it doesnt seem any more serious than that so im gonna have him throw a new one in and call this problem solved. cost and labor was way below what i expected..leaves me enough $$ for a new soft top, a weeks amount of $$ for parking at the Battery in NYC for next week's tests, and maybe a little bit of $$ left over so i can rip out that horrible dynomax garbage pipe and throw in banks headers and exhaust kit...gonna try and get that done when i have a little time to myself after my 3rd Mates exams.-ill prob run into a snag on that project, expect a thread titled "HELP! HEADER INSTALL, JEEP ON FIRE!!" lol.
thanks for all ur responses to this thread guys!
-stan