Replace rear brake cyllinders, rear brake pads, tank and left driveshaft

Take it back.

You will need to check things logically. Run the truck in the air and note where the vibration is at. Take the wheels OFF and put a few lug nuts to hold the rotors on, take the truck to 45mph or whatever the vibration is the worst. is it still there? if its gone, check wheels/ tires. if its still there, check rotors, axles. A drive shaft will make a rapid vibration at low speeds since it turns 3 to 4 times faster than the wheels. does it vibrate on or off the gas? Can you power through the vibration like go 60 and then coast back through? You have replaced a lot of parts that would not cause vibrations. Are you just changing parts willy nilly or is someone actually checking and verifying that these parts really bad?

Hello,
Brake Bleeding
Purging air and moisture from your binders
CarCare - Maintenance - Brakes

ABS Speed Sensor Service
A clean sensor is a happy sensor
CarCare - Maintenance - Brakes

Drum Brakes - Rear Brake Drum Adjustment
It's stupid not to adjust your rear drum brakes
CarCare - Maintenance - Brakes

Replacement Rotors
Friction, brake rotors, and you
CarCare - Maintenance - Brakes

Power-Bleeding Brake Systems
Air today, gone tomorrow
CarCare - Maintenance - Brakes

Replacing Brake Pads
How to replace worn pads
CarCare - Maintenance - Brakes

Bleeding Power Steering
Getting rid of that air in there
CarCare - Maintenance - BrakesThanks

Normal Maintenance Details
90,000 Miles (144,000 Kilometers) : All Applicable Models

INSPECT AUTOMATIC TRANSAXLE FLUID
INSPECT BALL JOINT & DUST COVERS
INSPECT BALL JOINTS
INSPECT BRAKE DISCS/ROTORS
INSPECT BRAKE DRUMS & LININGS
INSPECT BRAKE HOSES
INSPECT BRAKE LINE PIPES
INSPECT BRAKE PADS
INSPECT DIFFERENTIAL FLUID
INSPECT DRIVE BELTS
INSPECT DRIVESHAFT/PROPELLER SHAFT DUST BOOTS
INSPECT EXHAUST PIPES & MOUNTS
INSPECT FUEL LINES & CONNECTIONS
INSPECT FUEL SYSTEM
INSPECT FUEL TANK BAND
INSPECT FUEL TANK CAP GASKET
INSPECT FUEL VAPOR SYSTEM
INSPECT MANUAL TRANSAXLE FLUID
INSPECT STEERING GEAR/RACK
INSPECT STEERING LINKAGE
REPLACE AIR CLEANER/ELEMENT
REPLACE COOLANT
REPLACE ENGINE OIL
REPLACE ENGINE OIL FILTER
ROTATE TIRES

it sound as if you need to bleed the master cylinder to get the air out of the system give these websites a try www.autozone.com and www.alldatadiy.com if all fails stop by your local library and get your hands on a Haynes auto repair Manual for your car wish you the best of luck Michigan Man.

have someone take a look at the wheel bearings and tyrod ends, i know these will cause that, you may need these parts or you may be just lucky and a need a wheel balance and alignment, any general repair garage can take care of these problems

right rear, left rear, right front, left front. (left hand drivers side)

Normal Maintenance Details
90,000 Miles (144,000 Kilometers) : All Applicable Models
PERFORMED OPERATION COMPONENT
INSPECT BALL JOINTS
If equipped.
INSPECT BRAKE SYSTEM
Inspect brake pads, shoes, rotors, drums, brake lines & hoses.
INSPECT COOLING SYSTEM HOSES & CLAMPS
INSPECT DISC BRAKE PADS & ROTORS
INSPECT DRIVESHAFT
If equipped.
INSPECT DRIVESHAFT/PROPELLER SHAFT U JOINTS
INSPECT EXHAUST SYSTEM AND HEAT SHIELDS
INSPECT PARKING BRAKE SYSTEM
INSPECT STEERING LINKAGE
INSPECT SUSPENSION COMPONENTS
LUBRICATE DRIVESHAFT/PROPELLER SHAFT U JOINTS
LUBRICATE STEERING LINKAGE
REPLACE AIR CLEANER/ELEMENT
REPLACE AUTOMATIC TRANSMISSION FLUID
REPLACE CABIN AIR FILTER
If equipped.
REPLACE CLIMATE-CONTROLLED SEAT FILTERS
If equipped.
REPLACE ENGINE OIL
REPLACE ENGINE OIL FILTER
REPLACE FUEL FILTER
ROTATE TIRES
90,000 Miles (144,000 Kilometers) : RWD
PERFORMED OPERATION COMPONENT
LUBRICATE BALL JOINTS
2000 Lincoln Navigator
Maintenance
...sorry if not too readable

Hi Terry,
Please check out this Link : http://www.autopartswarehouse.com/featured/books_and_manuals/1461465620.html
Here you will find the details regarding your Car and how you can check and repair the breaks without taking it to a mechanic.
I hope this helps.....