New to me 2003 Suburban Z71 GMT800 5.3 LM7

[2018GMC]

Wasn’t looking for a suburban but a friend wanted it gone and the price was too good to say no. He did basic maintenance but it needed a lot to make it road trip ready.

 

It has 170k on engine. Transmission was replaced 15k miles ago. He only put 22k miles on it in 10 years of ownership.

Things I’ve done:
-Multiple degreases and pressure washing engine bay and underneath.
-Valve cover gaskets
-All 4 O2 sensors (Denso brand)
-Exhaust gaskets and Felpro bolts. Had to use Dorman fix on driver side rear bolt was broke off flush. But now no ticks when cold or hot.
-Main and ac serpentine belt
-Upper and lower large radiator hoses
-Torsion bar bushings and new 2” lift torsion keys
-1.5" rear coil spring spacers
-kyb monomax shocks all around.
-Alignment
-Intermediate shaft and lower steering column bearing
-All 4 window regulators
-Fuel pump with sender. Installed Flex fuel pump since it had "robust fuel level sender". Had to change flat 4 plug to square 4 plug but it dropped right in my vin T which is LM7 5.3 non-flex.
-Front diff fluid (terrible dirty, prob original)
-Rear diff fluid (not bad was changed 10 years ago)
-Autotrac transfercase fluid (the special blue Fluid (looked good was changed 10yr ago)
-At home trans flush to maxlife synthetic atf. Disconnected trans cooler line at radiator and pumped fluid till new came out. Also dropped pan and new filter. Fluid looked pretty good, some grey clutch material in bottom of pan and on magnet but pretty minimal.
-power steering flush
-engine oil
-Carpet cleaning
-Steering wheel buttons (lights were out)
-rear hvac actuator. (was stuck on ac (blend door actuator)
-Driver heated seat bottom and back new heating elements
-spark plugs and wires. Plugs I pulled out had ngk and part # on one side but acdelco and part # on other side. Thought they were counterfeit but sent pics to ngk they said they were oem plugs, could be original at 170k
-Front Brake pads, Rear Brake pads, Parking Brake shoes.
-Greased all fittings
-sway bar links
-Z71 factory running boards
-Denali cluster with trans temp gauge

-Idler and pitman arms were replaced 20k miles and 8yr ago.

I've now put about 2k miles on it and it hasn't missed a beat. The blackbear tune made the biggest difference in seat of the pants feel. Also firmed up trans shifts. Towing my 3500lb enclosed trailer, it doesn't do as well as my 97 k1500 with 5.7 also blackbear tuned. Both are 3:73 gears. But the 5.3 does alright just has to downshift and rev sooner than the 5.7.

[2018GMC]

I've done all the work myself except for the alignment and enjoyed most of it. Everything seems good now except I dont get sound from speakers when temps are cold 40F and below (no chime or radio even though radio turns on) After the interior warms up you hear a pop and sound works as it should. This summer it hasn't missed a beat.

I replaced the bose amp under the center console but issue still persists. Tried replacing the head unit with another one from junkyard but found out about theftlock. The few places I find on ebay and internet say they don't reprogram bose radios. I may try reflowing solider with a heat gun on the original head unit.

Front bumper needs a repaint (tons of rock chips)
Rear bumper needs replaced (dented)

Of course all the bumpers i find in junk yard are usually beat to hell or not the z71 version.

Also a meguiars M105 / M205 cut and polish. Unfortunately it has some deep pin striping down the side but it looks great 15ft away lol. A lot of this gen I see around has severe paint fade and peeling. So far this pewter has held up very well for 20 year old paint.

Performance upgrades:
Blackbear tune
Magnaflow 12588 performance muffler
AFE cold air intake.

 

Edited July 17, 2023 by 2018GMC

[txab]

[2018GMC]

Videos of the suburban on my channel along with some other vehicles in the family fleet.

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