Hey everyone, im new to this forum and new to jeeps. I bought my 95 yj almost a year and a half ago it had 93000 on it and first thing i did was take it in for a full service. Everything seemed to be going great until last wednesday I noticed that it started a knocking sound. It begins knocking in the higher range of rpms in first gear and then it gets louder and faster as i shift through the other 4 gears. It has the 4 cylinder with the ax5 transmission and the 231 transfer case. It only knocks when I am accelerating as soon as i let up on the gas it stops. Changed the transmission oil and transfer case oil and hasnt helped any. Ive talked to my uncle who is a gearhead and a neighbor that is a retired mechanic, uncle was stumped and the neighbor said he thought it was the transmission going. The kicker is that it only knocks in 2wd but when i put it in 4wd the knocking stops. I can really feel the knocking on the 4wd shifter knob but not as much on the shifter knob but that has a lot of play to it so it might not transfer the knocking as much. Any inputs great. Im hoping it cud be a simple fix but im expecting that it isn't. Any ideas?
From reading on here and personal experiences check your exhaust manifold, they crack all the time and amplify the normal engine tick all jeeps love to have. I hope for you it's an easy fix best if luck
If the above isn't it, start with elimination. Check for play in your u joints, take the front DS off and see if it still knocks, if you plug the TC output you can also pull the rear DS and drive with the front alone.
I thought maybe it was the exhaust too and the exhaust pipe was loose but it got that tightened back down and the u joints are tight. From who ive talked to they say it cant be the manifold because the noise stops as soon as i let up on the gas if its in gear and if its not in gear i can gas on and it sounds normal. which leads me to belive that it is something in the transfer case or the transmission.
If it's not in the drive train, by elimination it sounds like it would be the TC. If it was the transmission shifting to 4x4 would not eliminate it. The TC chain can be loose but it shouldn't be moving in 2x2, the reason I bring up the chain is shifting into 4x4 would put it under tension.
I just made sure that the u joints were tight and didnt have any slop in them and they are snug. nothing has changed with them. The noise just started. I had to drive to work about a mile from my house and it was fine and when i left work i headed into town about 12 miles and it started about half way there. I stopped at a stop sign and everything was ok and when i got into second gear from the stop sign it started knocking. I didnt dump the clutch or start hard or anything either i drive it pretty easy as i cant really afford to break anything on it. But Ill try taking the drive shaft off and do what you said. Appreciate the ideas. Glad I joined the forum.