Mitsubishi Repair: rear end vibration., mitsubishi montero sport, mitsubishi montero

Question
I have a 1999 Mitsubishi Montero sport XLS Automatic.
When I reach about 40 MPH a vibration occurs in the rear of the vehicle. It
sounds like a wheel vibrating, but the wheels have all been checked by my local
shop. They can find no cause for this intermittent problem. It seems to be worse
in cold weather. The shocks have also been replaced.
Could it be the rubber mounts on the rear of the transmision housing?

Also is it possible to change my own timing belt? The vehicle has 60,000 miles.
Do you have an extract of a manual that may help?
Thanks
Chris

Answer
Chris,
If your mechanic tried to rebalance the wheels but it still didn't help, you may have tread seperation.  Tires are manufactured in layers.  Sometimes the tread layer or even the steel belt can twist, seperate, or even break.  There is no visual evidence of any problems, but the tire should be replaced.  If all 4 tires have 40,000 miles or more on them, you may just want to replace them all.

Replacing the timing belt can be a difficult procedure.  There is a special tool the dealership uses to hold the crank still when they remove the crank bolt.  The torque on that bolt is usually over 100 ft-lbs, so it takes a lot of force to remove it.  The best manual is the factory service manual.  I do not have any services manuals for your particular vehicle, but you can order one from any Mitsubishi dealership.
Good luck!