Knocking noise on the floor

Snowboardingmofo

New Member
Joined
Dec 1, 2005
Location
Concord, NC
I've got a 97 TJ Sport that I just lifted with 2" of Body, 3" suspension and 35" tires. I am running stock gears (for now), and every time I start out and let off the clutch in 1st gear I get a strange knocking sound for a split second that I can hear and feel around the pedals on the floor. I checked everything out to make sure nothings loose but I can't figure out what it is. I don't think its the driveshaft cause it sounds like its coming from towards the front. If anyone could help me out I would appreciate it. Thanks.
 
Sounds like axle wrap. Have someone watch your pinion angle as you start off.
If not that, check motor mounts and tranny mount.
 
Mine does that too and I'm gonna try to fix it today. I dont have the same setup as you so my cause may be slightly different. The problem I have is that my muffler rattles against my skidplate when i take off from a dead stop. I assume it's because the torque of the motor is trying to get the tires going and it's difficult because I dont have my axle gearing correct. This makes the muffler drop and hit the skidplate for a few seconds, which i can feel on my feet. Right now i've shoved a pice of wood as a buffer between the muffler hanger and skidplate as a temporary fix. we'll see what I can come up with today.
 
Did you correct the transfercase shifter geometry when you did the lift? If you didn't the shifter linkage can be binding an slapping the floor board when you torque up in first. If your getting axle rap with a tj suspension, now that would be puzzling. You shouldn,t that much if any.Also you didn't state if its just in 2 or 4wd, 2wd there would be no torque on front axle, that would cancel out the frontend. Unless something is loose or binding in the suspension.
 
We just put a 3.5" on our TJs and have the same thing plus other rattling. One was a squeeking knock and turned out to be the side step (tubular and mounted to bodymounts). We still have a knock and vibration complete with the shifter rattle and from what i can tell, it did not seem to be coming from the rear driveline, but the more i check the more I think it is (the t-case is almosr right under the front seats). To test it i filled the gas tank and loaded some extra weight into the back to compress the rear suspension and flatten the rear drive angle some. Needless to say the knock and vibration were reduced verifying that a SYE was a must. Have not checked the tranny mount yet, but planning on it today. If that is the issue i will let you know since we have the same thing going on.

Tony
 
Yeah, the shifter has a vibration when the knocking noise happens. I was trying to avoid a SYE but looks like I might have to get one. RedJP, let me know if you figure out what the noise is. Thanks.
 
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