Grinding noise when accelerating from stop

JeepinMiller

New Member
Joined
May 22, 2019
Messages
7
Location
Sevierville, TN
1997 Jeep Wrangler 4.0 Liter. When taking off there is a grinding noise which sounds like it is coming from the front of the vehicle. I have tried in both first and second gear and the grinding sound is there. Roll starting in neutral there is no grinding sound. Also I lifted the Jeep off all four wheels with jack stands, started the Jeep and shifted into first and second with no grinding sound in both 2 WD and 4WD. Grinding sound only occurs when accelerating from a stop. Please help.
 
Vehicle does have a 4” rough country lift with new control arms and a transfer case drop. 35” tires. Grinding sound occurs when driving straight and turning.
 
When you had the jeep on the jack stands, where were they placed? Under the frame or under the axles? I'm thinking sprung vs unsprung weight on things.
 
Could be your driveshaft ujoints. With the lift, angles change and cause problems.

You can try lifting it again from the axles. Put the ebrakes on and shift through gears to put some load on the driveshaft. Don't burn the ebrakes though.

You can also try removing the rear and front driveshafts one at a time to isolate the problem while driving in 4HI.
 
To me it sounds like brake drag. After a full stop the brakes have been fully activated. Start moving and you hear them because they didn't move off the rotor enough. Try on jackstands, motor running to activate the vacuum for brake booster. Step on brakes Hard, like you would at a Stop sign. If possible have a budy there to see what is happening at each rotor. And then after foot off brake if they can easily turn the rotor by hand. Dial brakes use a slight amount of residual pressure to keep pads near the rotor. My guess is that your system is holding too much line pressure or possible warp rotor.
 
Or a rock in the dust cover and with the wheels on the ground it flex’s just enough to make it grind. Been in some sloppy fun prior to the grinding?


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I’ll have to check the driveshafts. I got under it and shook them real hard but no play in the u joints. Nothing crazy mostly dirt and gravel roads. When the Jeep is lifted and I spin the tires there’s no grinding and no grinding when rolling forward in neutral from stop either.
 
My brother came over to drive the Jeep so I could get under it and listen while he drove. It turned out to be the exhaust rattling against the skid plate by the transfer case. The bottom part of the weld by the muffler had broken causing the muffler to sag.

Thank you for all of the advice some everyone. Turns out to not be a big problem at all. A little weld and we’re back in business