Replaced power steering unit on 2002 trailblazer 4wd, still hard to turn steering wheel while stop and slow speed when taking off !!!!!!!!

Vehicles: 2002 Chevrolet Trailblazer 4WD 4.2L SFI DOHC 6-cylinder

Your front 4WD Transfer case is low on Gear Oil.
On warm days, the Gear Oil expands slightly, and is less viscous, so the "Service 4WD" light stays off. On colder days/mornings the story changes.

The following paragraph has info applying to the manual differential only:
The 2002 Trailblazer (the first year Chevy made the Trailblazer) has a Front Differential using 1.11 (that's 1 and 1/9th) Quarts Gear Oil, and a Rear Differential with a capacity of 2.29 (thats 2 and 2/7ths) Quarts Gear Oil.
The Gear Oil needed is GM Part No.12345349 or GM Part No.1052931 (they're identical), also known as "GM Synchromesh"(R), which is a type of GLS (Gear Lubricant, Special), also known as "Manual Synchromesh Transmission Fluid 5W30". A synthetic version of which sells for $12.70/qt (USD) at
http://www.amsoil.com/storefront/mtf.aspx

This is not to be confused with 5W30 motor oil (which can be had for $3.00/qt (USD)).

The 2002 Trailblazer 4WD Transfer Case (NV126 Transfer Case) capacity is 0.8 Liters of GM Part No.12378508 (US), also known as "GM Auto Trak II"(R).
Note that one Quart (US) = 0.946 Liter, so 0.8 Liter = 27.06 ounces.

Red Line sells something that they say replaces both GM Synchromesh and GM Auto-Trak II for $12.14/Qt and $44.55/Gal (US) at
http://www.shopwiki.com/Red-Line-MTL-70W80-GL~4-Gear-Oil-%281-Quart%29

13 Manufacturer Recalls apply to the 2002 Chevrolet Trailblazer (model year 2002 was the first year Chevy offered the Trailblazer), and two recalls pertain to the 4WD Transfer Case. Note that one of the recalls applies to only 895 units, so your vehicle is unlikely to be affected by this Transfer Case recall.

2002 Trailblazer Recall ==========================
OCT 17, 2001 ' Recall ID# 54221

Recall Reason POWER TRAIN:TRANSFER CASE (4-WHEEL DRIVE)
Recall Date OCT 17, 2001
Model Affected TRAILBLAZER
Potential Units Affected 78004

Recall Summary
VEHICLE DESCRIPTION: SPORT UTILITY VEHICLES EQUIPPED WITH 4-WHEEL DRIVE. THE CALIBRATION OF THE TRANSFER CASE CONTROL MODULE COULD CAUSE INSUFFICIENT HIGH SPEED GEAR ENGAGEMENT.

Consequence
IF THE GEAR IS NOT ENGAGED, THE VEHICLE CAN ROLL WHEN THE TRANSMISSION IS IN "PARK" AND A CRASH COULD RESULT WITHOUT WARNING.

Remedy
DEALERS WILL UPDATE THE TRANSFER CASE CONTROL MODULE CALIBRATION TO INCREASE GEAR ENGAGEMENT. OWNER NOTIFICATION BEGAN NOVEMBER 6, 2001. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT CHEVROLET AT 1-800-222-1020 OR GMC AT 1-800-462-8782.

Notes
GENERAL MOTORS CORP. 01064/01065

2002 Trailblazer Recall ============================
SEP 05, 2001 ' Recall ID# 26006

Recall Reason POWER TRAIN:TRANSFER CASE (4-WHEEL DRIVE)
Recall Date SEP 05, 2001
Model Affected TRAILBLAZER
Potential Units Affected 895

Recall Summary
VEHICLE DESCRIPTION: SPORT UTILITY VEHICLES (4 WHEEL-DRIVE). SOME OF THESE VEHICLES WERE BUILT WITH A RANGE SHIFT COLLAR IN THE TRANSMISSION TRANSFER CASE THAT CONTAINS CRACKS.

Consequence
THIS CONDITION COULD RESULT IN A COMPLETE FRACTURE OF THE RANGE SHIFT COLLAR AND SUBSEQUENT LOSS OF VEHICLE FORWARD AND REVERSE GEARS, AND THE INABILITY TO MAINTAIN "PARK" POSITION. THIS INCREASES THE RISK OF A VEHICLE CRASH RESULTING FROM UNINTENDED MOVEMENT OF A PARKED VEHICLE.

Remedy
DEALERS WILL REPLACE THE TRANSFER CASES AND UPDATE THE CONTROL MODULE CALIBRATION. OWNER NOTIFICATION BEGAN SEPTEMBER 6, 2001. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT CHEVROLET AT 1-800-222-1020 OR GMC AT 1-800-462-8782.

Notes
GENERAL MOTORS CORP. 01061


Read about all (13) 2002 Chevy Trailblazer recalls at:
http://www.internetautoguide.com/10-12-2002-16-1287/2002-chevrolet-trailblazer-recalls.html

YOU HAVE AIR IN THE POWER STEERING SYSTEM.YOU NEED TO BLEED POWER STEERING PUMP FIRST BEFORE DRIVING VECHICLE.CHECK POWER STEERING FLUID LEVEL ADD MORE POWER STEERING UNTIL REACH FULL COLD MARK..RAISE VECHICLE FRONT WHEELS OFF THE GROUND.START ENGINE LET IT IDLE WHILE TURNING STEERING WHEEL LEFT TO RIGHT NON STOP DONT LOCK OR STOP STEERING WHEEL KEEP TURNING IT SEVERAL TIMES CHECK POWER STEERING FLUID IF LOW ADD UNTIL YOU GET COLD MARK ON DIP STICK DONT OVER FILL POWER STEERING PUMP BLOW A SEAL.IF POWER STEERING FLUID LOOK TAN COLOR SYSTEM FULL OF AIR.TURN OFF IGNITION LET CAR SET FOR A WHILE CHECK FLUID LEVEL.IF STEERING WHEEL FEEL STIFF HARD TURNING DONT DRIVE CAR UNTIL YOU HAVE NORMAL STEERING.IF STILL HAVE AIR IN SYSTEM BLEED SYSTEM UNTIL AIR IS OUT.

The vehicle is going to be very hard to steer at slower speeds and very tough at complete stops. You will also damage the other p/s components and cost yourself a lot more money!

Worn steering components which allow the steering wheels to travel too far either way,hop underneath and get a friend to move the steering while you have a look for movement between the components, or a power steering component like relief valve. Its a bit hard to know without seeing the vehicle, i suggest a steering and suspension specialist like pedders or similar.These guys can do a safety inspection only, if you want to do the work yourself. Cheers Timo.

power steering unit needs to be replaced. the booster is not working good. sry.

If its in 4WD thats normal. On hard, dry, pavement its binding up because the front wheels and the rear wheels are turning at different speeds.

This sounds like a bad flasher unit. Simply by replacing this unit should fix this problem. Usually they are located on the top of the steering wheel beneath the trim. You have to disassemble the trim around the steering column.

Replace power steering pump

Take a picture of it before you take it apart so you know where everything goes.
1.Take belt off
2. Unbolt any bracket that the power steering pump is bolted too.( only if you have to unbolt a bracket)
3. Disconnect lines from steering pump
4. After replacing power steering pump fill with Auto. trans fluid.
5. After filling start car and turn wheel left and right a few times this will get the air out of the system and recheck fluid level.

I had a similar problem with a popping - clanking noise when I was turning the Steering Wheel and going at a slow speed.
See if you can have someone listen outside the car while you drive it to be sure.
I replaced the one drive axle and the problem was solved.