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problem after tcase drop removal

X

XJ99

NAXJA Forum User
Location
Newark, DE
my rig was recently upgraded to a 6.5", 35's, sye, tom woods shaft, so I finally got around to removing the tcase drop today a week after the suspension and sye was put on. Everythings been riding smooth. I removed the tcase drop today put new bolts in, and when I go to drive theres a knock sound coming from under the Jeep. I checked the front ds and It seems as though Its clearing everything fine, I cant think of what else It can be so I put the 1" drop back on with the old bolts and the knock is gone.....I cant hear It from the outside of the Jeep, only when Inside, Its in forward and reverse...any thoughts?
 
Did you shim the axle so the yoke is about 1 degree below being in line with the sye? If not, removing the drop would make the angle even worse.
 
Ill bet its part of your exhaust banging on the underside of your Jeep....when you removed the TC drop, it moved your exhaust up a little too....if you had hit it before and already pushed it up, raising the TC back up probably put it even closer. Id check that first.
 
the rear axle is shimmed at 6 degrees....Im gonna check the exhaust, because while I thought It could only be the front ds, It does sound like Its more towards the passenger side...but If Its the exhaust why would It be a knock when the tires rotate? As I move forward or go in reverse Its knock, knock, knock....?
 
oh yea...I dunno why shimming the yoke would do anything because the sound is coming from up front....also Its not a ratling sound, Its a knock when the tires rotate, when Im in neutral or park theres no sound, so would that count the exhaust out?
 
My bet is on the exhuast as well. The torque of the motor will move it when selecting forward or reverse and removing the drop lifts it up an 1" closer to the floor.
 
XJ99 said:
oh yea...I dunno why shimming the yoke would do anything because the sound is coming from up front....also Its not a ratling sound, Its a knock when the tires rotate, when Im in neutral or park theres no sound, so would that count the exhaust out?
Click to expand...

Oh, the front....
 
Gojeep said:
My bet is on the exhuast as well. The torque of the motor will move it when selecting forward or reverse and removing the drop lifts it up an 1" closer to the floor.
Click to expand...
Probably a worn tranny mount. I had the same problem/noise when my tranny mount was worn and the tcase was moving up and down with the revs.
 
XJ99 said:
the rear axle is shimmed at 6 degrees....Im gonna check the exhaust, because while I thought It could only be the front ds, It does sound like Its more towards the passenger side...but If Its the exhaust why would It be a knock when the tires rotate? As I move forward or go in reverse Its knock, knock, knock....?
Click to expand...

While i cant give you an exact explanation, it just does...take a look at exhaust when someone takes off from a dead stop....they usually bounce up and down or go side to side a little bit due to the torque of the motor twisting the exhaust, etc. If its close, its thumping on you undercarage somewhere causing a knocking sound...took me a month and several hours under my XJ to figure out what the heck that noise was. Mine was most pronouced upon heavy acceleration in forward or reverse.
 
Like Kejtar said about the exhaust. Especially if you have the coffe can (round) cat converter. Basically all the pressure on the driveline makes it vibrate hitting the x-member. Im running a 6* shim as well but that says nothing. You need to look and see where your pinion sits too. I would proably count out the tranny mount if it only does it with the drop out.
 
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