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MatthewC85 09-16-2013 09:29 PM

Knocking underneath driver side / front
Jeep started knocking only during hard acceleration about a week or two ago. does not make the noise in park or neutral ( I can rev the crap out of the engine no noise) nor does it make a noise while driving under normal circumstances (slow acceleration normal day to day driving). It can be only heard up hill / highway speed acceleration , could this be a slight leak in the manifold or something drive shaft U-joint related? Reason im leaning towards manifold is the location of the knocking/clicking noise and to me it just sounds like a gas leak however im asking this question because -- can a gas leak in the manifold area be only heard under heavy load and not under high rev in neutral or park? doesn't make much sense to me which than makes me lean towards driveshaft?

Jeep Tj 181 000km rebuilt engine at 145 000km

brs256 09-16-2013 10:34 PM

look at your transfer case shifter linkage ... slop will cause a knocking sound

Owen_TJ 09-16-2013 10:51 PM


Originally Posted by brs256 (Post 4632353)
look at your transfer case shifter linkage ... slop will cause a knocking sound


BlaknBlu 09-16-2013 10:52 PM


Originally Posted by brs256 (Post 4632353)
look at your transfer case shifter linkage ... slop will cause a knocking sound

yep, I had to tighten mine up to get rid of the knocking noise.

MatthewC85 09-16-2013 10:53 PM

checked that out the other day looked fine also there is no vibration in the shifter and it shifts perfectly . any other ideas?

MatthewC85 09-16-2013 10:59 PM

just to add the noise is more front end. to narrow it even more probably near my foot when the gas pedal is being pressed the knock is not felt ( floor is not shaking) its more just heard. which is why i automatically thought manifold gasket or the manifold itself. however the noise is not apparent in neutral or park which threw me a curve ball.

Owen_TJ 09-16-2013 11:02 PM

My vote is still the tcase linkage...are you lifted??? have you adjusted the linkage at all?

go under it, loosen the bolt on the linkage, then have someone hold the lever down inside the vehicle while you tighten it.

Or, as a little test, try to slightly pull up on the tcase lever (quarter to half inch) and see if the vibration/noise goes away.

I used to have a vibration and when i adjusted the linkage it went away.

MatthewC85 09-16-2013 11:10 PM

Ill give the test a shot tomorrow. im also going to try and record a video of the noise. post it up on this thread. Thanks

as for your first question yes , I am lifted 3.25 inch or basically a budget boost with a spacer to 3.25. the linkage was adjusted when i did the lift about 4 or so years ago the shocks were recently changed that's about it.

Owen_TJ 09-16-2013 11:17 PM

i definitely think its your linkage...

good luck with it tomorrow

BlaknBlu 09-16-2013 11:32 PM

Mine was where the TC shift linkage attaches to the tub under right foot. I had to pull back the carpet to get to the bolts inside, hold them while someone tightened from underneath.

MatthewC85 09-18-2013 05:12 PM

Update . Checked it out further and we narrowed it down to the manifold gasket or manifold itself. buddy of mine told me not to deal with it now to continue driving with it the way it is. Ill upload a video in a few.

jherrington 09-18-2013 08:31 PM

Does it sound like a rattle? Like a marble in a can?

MatthewC85 09-18-2013 09:43 PM

Nope , sounded like a gas leak which is... 95% probably what it is. Ill have to remove the manifold and give it a check if its not that its the gasket. Id seafoam it if i didn't just change the oil .It only makes the tick/knock at full load while in drive. if you drive normally without flooring the 4 banger or going up a steep hill it really wouldn't be a problem for concern , just i live in a hilly area and its become someone of a nuisance for me hearing a 2.5L sound like a diesel. The crack must be hairline for now which is why in neutral or park flooring it the sound is faint to non existent. Its only apparent when you hit the gas hard while in drive.

If however this is not the problem I believe my head will explode.

Tip and Ring 09-30-2013 07:06 PM

Same Thing Here !
My 02 TJ with a 1" body lift started doing this the other day. The noise and a slight tap can be felt/heard at the gas pedal area. I have used a Teraflex Linkage adaptor, and had to do a lot of adjustment. I have replaced the head about 5,000 miles ago due to an overheat and head crack (old 0331) I replaced all of the gaskets when I did this and installed the head with the intake/exhaust manifold attached. I was worried about gaining an angle for the torque down. I pulled the front driveshaft tonight with the idea that one of the joints in the shaft was binding but the noise returned. I am going to try these fixes you guys mentioned. Anybody have any other ideas?

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