I own a 2002 montero XLS. The problem is that at 55 - 65 a vibration starts then worsens to a hard hittins shudder like the antilock brakes are "slamming" once I press the brake pedal. I've repla

SOURCE: transmission vibrations to heavy shaking between 30-45 mph

tranmission mount is broke change it before it breaks your motor mounts.

SOURCE: brakes grindind at low speed

Sounds like your getting abs activation when its not needed. Most likley one of the wheel speed sensors has failed. You do need to have a scan tool to read the live data from the abs module as the problem is occurring to pinpoint which sensor is faulty. The abs light will not come on because the abs module thinks its just working normally. I'm an ASE certified mechanic and have seen this problem many times on various vehicles. You might have to pay somebody to diagnose it, but replacing the sensor it a very easy task. I hope this helps.

SOURCE: Car shudders when accelerating...

My wife's 02 Audi A4 1,8t had the same problem after talking with Audi (coil pack/spark plugs) we replaced them all and the problem still persisted not to say that won't fix your problem but what I found to be the problem was 3/8 vacuum line (shaped like a S) that comes up on the right hand side between the oil filter and the fire wall that comes from the turbo check valve assembly (its hard to locate and should be done with the engine cool) up to a valve assembly that connects to the intake manifold, what was happening was the hose would become spongy at the bottom (you will have to squeeze the hose from top to bottom to notice the difference) and as the engine heats up it would cause the hose to collapse. Once I replaced the hose and the computer reprogrammed the fuel mixture (about 25 miles of driving) the problem seems to have been correct. Good luck.I had also replaced the turbo check valve about three years ago because of a severe hesitation when you first apply gas (turbo check valve may not be the proper name.) Sorry. Wife Still Loves Her Audi

SOURCE: 2001 NISSAN QUEST VIBRATION

THE ORIGINAL VIBRATION MAY HAVE BEEN TIRES.IF THE LUG NUTS WERE NOT TORQUED BY HAND BUT OVERTIGHTED W/AN AIR RATCHET THE ROTORS MAY HAVE BEEN WARPED.TAKE IT BACK TO WERE THE TIRES WERE INSTALLED AND ASK THEM TO CHECK IT OUT.

SOURCE: Vibration/Rattling on right side during high speeds

I had a similar problem. The dealer change automatic transmission and differential, but the noise continu. After research on internet i think the problem is the front galiper who create a vibration on the disc wheel and the vibration frequence follow the front axle until interior car. Just press slowly the brake pedal and if the noise stop , that's it the cause i think. I dont change my galiper, but i have a new transmission . :)))