2009 silverado Hi I just bought a 2009 Chevy silverado LTZ 1/2ton automatic i i noticed that sometimes the lights flicker slightly when it shifts from first to second gear and also from 2nd to first. I'm assuming there is some sort of draw on the battery /Altinator. Any tips on figuring this out would be great.

First you need to have EBCM - electronic brake control module check for DTC'S - diagnostic trouble code's . If the light is on there is a code stored . I think most part stores can do this and for free . After you find out what code is stored , looking up that code in service repair information for diagnostic trouble shooting chart would be next step . There are a few codes too.
DTC C0035 or C0040
DTC C0045 or C0050
DTC C0110
DTC C0131
DTC C0161
DTC C0186
DTC C0196
DTC C0201
DTC C0240
DTC C0241 or P0856
DTC C0244 or P1689
DTC C0245
DTC C0283
DTC C0287
DTC C0290 or C0292
DTC C0455
DTC C0550
DTC C0558

Find the code do the diagnostic's , fix the problem , wiring issue's , a sensor , bad module ,what ever it is . The light will go out then . Here is a sample of code discription .
• DTC C0035 Left Front Wheel Speed Sensor Circuit
• DTC C0040 Right Front Wheel Speed Sensor Circuit

i take it is a automatic check gearbox transmission fluid or the torque converter may be at fault

It's trying to tell you there is a problem an you need to have it checked, DTC - diagnostic trouble code stored in The HVAC control module !

Do you have a question? or are you making a statement? Did you drive for quite a bit while leaving the e-brake engaged? if so you will probably need a new set of pads and possibly new rotors if they got too overheated.

Make sure your tranny cooler Isnt pluged and there are no kinks in the lines to the cooler and back.

For gear shift issues and gear stuck issues,the help links are provided below. Click the link below to go through troubleshooting procedure:---- ---- Car will not move when in gear?

http://repairhelpcenter.blogspot.in/2012/02/car-will-not-move-when-in-gear.html ---- transmission sticks in first gear? http://technoanswers.blogspot.com/2012/01/mercedes-benz-transmission-sticks-in.html ----- Transmission not engaging in first gear? http://technoanswers.blogspot.com/2012/01/mercedes-benz-not-engaging-in-first.html ----- Vehicle only goes in First gear?

http://howtobyme.blogspot.com/2011/11/chrysler-pt-cruiser-only-goes-in-first.html

----

Car is stuck in park and the shift will not move?

http://howtobyme.blogspot.com/2011/08/car-is-stuck-in-park-and-shift-will-not.html

---- Engine will not go out of park mode? http://technoanswers.blogspot.in/2012/02/2002-nissan-sentra-will-not-go-out-of.html ---- Car stuck in park? http://technoanswers.blogspot.in/2012/02/nissan-sentra-stuck-in-park.html ----- Car will not come out of Park?

http://howtobyme.blogspot.com/2011/11/car-will-not-come-out-of-park.html

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Automatic transmission will not go into high gear?

http://howtobyme.blogspot.com/2011/11/automatic-transmission-will-not-go-into.html
--- Car wont downshift sometimes?

http://schematicsdiagram.blogspot.com/2011/12/car-wont-downshift-sometimes.html
---- Transmission will shift into drive?

http://schematicsdiagram.blogspot.com/2011/12/buick-park-avenuetransmission-will.html
----- Auto wont shift from park? http://schematicsdiagram.blogspot.com/2011/12/ford-taurus-wont-shift-from-park.html ---- Car Transmission will not go into Park mode?

http://schematicsdiagram.blogspot.com/2011/12/car-transmission-will-no-go-into-park.html
----- Shift indicator directly goes to 2nd when key is turned ON?

http://schematicsdiagram.blogspot.com/2011/12/shift-indicator-directly-goes-to-2nd.html
---- Third gear missing and engine losing power?

http://schematicsdiagram.blogspot.com/2012/01/third-gear-missing-and-engine-losing.html
------- Vehicle has whining sound in gear?

http://technoanswers.blogspot.com/2012/01/chevrolet-silverado-has-whining-sound.html
----- Hard to shift gears on Manual transmission?

http://technoanswers.blogspot.com/2012/01/hard-to-shift-gears-on-manual.html
------ Car hard shift at slow speeds?

http://technoanswers.blogspot.com/2012/01/car-hard-shift-at-slow-speeds.html
--- Automatic transmission shift lever hard to move on cold mornings?

http://technoanswers.blogspot.com/2012/01/automatic-transmission-shift-lever-hard.html
------ Gear shifts hard?

http://schematicsdiagram.blogspot.in/2012/02/2000-nissan-maxima-shifts-hard.html
------- Vehicle noticed sluggish delayed shifts while driving?

http://schematicsdiagram.blogspot.in/2012/03/vehicle-noticed-sluggish-delayed-shifts.html

-------

This will help.

Thanks.

check your fuses

i would first have alternator and battery checked
if either is bad it is not keeping up the demand for electric current which will in turn cause lights to flicker and computer to malfunction

Which one of these 4X4's does your vehicle have ?
Transfer Case - NVG 246-NP8 (Two Speed Automatic)
Transfer Case - NVG 261-NP2 (Two Speed Manual)

Run a code reader. Sensor problem I bet