2001 Chevrolet Silverado 2500HD: When shifted into Drive or Reverse, engine will Not Rev up.

SOURCE: locate the oil sending unit on a 2003 6.0 2500HD silverado

You will find it down by the oil filter.

SOURCE: 2001 chevy sylverado 2500hd power steering and power brakes quit

check power steering fluid. first. if all good . power steering is going. your hydro boost brake system depends on the power steering pump if it goes out your brake go out.

SOURCE: 2005 Chevrolet Silverado 2500HD 4x4 Oil Change Reset

Not positive 05 is the same but on my 02 you turn the key to the on position and pump the gas pedal 4 times.

SOURCE: 2001 Chevrolet Silverado How to remove rear axle

Remove...
wheels, drums or rotors, the cover for the differential (You will need a drip pan)
remove the "pin" (usually a 5/15" or 8mm head) that secures the spider gear pin. Remove the long spider gear pin, as it should slide out without a lot of force.
Push both axles inward, and remove the left and right "c" clips that hold the axles in.
Note... if you have a limited slip, it may be a little different of a set up due to clutches in the differential.

SOURCE: 2003 CHEVROLET SILVERADO 2500HD 6.0

4.8L, 5.3L & 6.0L Engines

1. Remove the air inlet duct.
   
2. Drain the cooling system.
   
3. Remove the radiator outlet hose.
   
4. Remove the thermostat housing bolts.
   
5. Remove the thermostat from the water pump housing.
   

The O-ring seal is integral to the thermostat housing

Thermostat housing-4.8L, 5.3L and 6.0L engines

To install:

1. Install the thermostat to the water pump housing making sure the spring side is inserted into the engine.
   
2. Install the bolts.
   
   • Tighten the bolts to 11 ft. lbs. (15 Nm).
     
3. Install the radiator outlet hose.
   
4. Fill the cooling system.
   
5. Install the air inlet duct.
   
6. Test the system for leaks.
   

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