2003 Suburban Z71 redo

[555hp]

With 5.3L flex engine and most every option ordered, 155K miles.

My burb (original owner) turns 20 next week and I am giving her a complete redo for her birthday (this started off as just fixing up the paint). Took care of many of the common problems (IP, fuel pump, etc), but on the fence about some others (transmission). Toward that, I seek advise on what more knowledgeable people would do with this transmission at this age (keep up with fluid changes and it had some solenoid replaced 10 yrs ago). Since the engine is known to be good for another 150K, and since I live in rust free AZ, the only things I need to worry about is the trans, AC and plastic parts (which seem hard to find, currently looking for the D pillar plastic vent panels).

I appreciate any advice on the transmission (and other things to improve). I'm currently thinking a rebuild is appropriate (with possible upgrades to the 4L80). I would like to upgrade the a 6 spd, but not sure it's worth the trouble.

I expect to keep her another 10 yrs or so, possibly pulling a trailer.

 

[clandr1]

Is the trans acting up? If not, continue with pan drop, change filter, and refill pan every 50k miles (in my opinion). My truck (which I'm the original owner) has 253k on the original transmission.

 

[ncalvo]

With 5.3L flex engine and most every option ordered, 155K miles.

My burb (original owner) turns 20 next week and I am giving her a complete redo for her birthday (this started off as just fixing up the paint). Took care of many of the common problems (IP, fuel pump, etc), but on the fence about some others (transmission). Toward that, I seek advise on what more knowledgeable people would do with this transmission at this age (keep up with fluid changes and it had some solenoid replaced 10 yrs ago). Since the engine is known to be good for another 150K, and since I live in rust free AZ, the only things I need to worry about is the trans, AC and plastic parts (which seem hard to find, currently looking for the D pillar plastic vent panels).

I appreciate any advice on the transmission (and other things to improve). I'm currently thinking a rebuild is appropriate (with possible upgrades to the 4L80). I would like to upgrade the a 6 spd, but not sure it's worth the trouble.

I expect to keep her another 10 yrs or so, possibly pulling a trailer.

Replace/upgrade worn parts like steering/suspension/brakes. Replace all the fluids.
Just rebuild/upgrade trans when it is needed and for what you use it for.
I rebuilt my 4l60e before it was needed and went for minor upgrades (sunshell, servo etc) If you plan to tow maybe upgrade the trans cooler and add trans temp to your cluster.
Plastic parts are best found cheap and easy at the junkyard

 

[Marky Dissod]

Do you mind if I think it's far more likely you've a 4L60E? Check the SPID sticker in the glovebox.
M30 = 4L60E most likely
M32 = 4L65E upgrade your 4L60E as if it were this at minimum

I prefer DuraLube's ATF.
If you're in the mood for upgrades, assuming your axles are 3.73, you may prefer 4.10 or 4.30, especially for towing.
(I haven't even towed anything yet with 3.73, and I find 3.73 BARELY TOLERABLE.)
I'll second the recommendations to upgrade the external ATF cooler and add an ATF temp gauge.

If you're afraid that you might need a rebuild BEFORE a big towing trip, have your used ATF analyzed.
The analysis will let you know if / when you need a rebuild.

 

[555hp]

Replace/upgrade worn parts like steering/suspension/brakes. Replace all the fluids.
Just rebuild/upgrade trans when it is needed and for what you use it for.
I rebuilt my 4l60e before it was needed and went for minor upgrades (sunshell, servo etc) If you plan to tow maybe upgrade the trans cooler and add trans temp to your cluster.
Plastic parts are best found cheap and easy at the junkyard

Thanks! I already added the teans temp (easy add with the stepper motor) and it already has a trans cooler from the factory toew package (though may be worth a better cooler).

 

[Jocko PDX]

I still have my 2003 Z71 burb. 2077K miles and still runs awesome. What a great vehicle it is. I wish I had bought 2!!

 

[Fless]

I still have my 2003 Z71 burb. 2077K miles and still runs awesome. What a great vehicle it is. I wish I had bought 2!!

Over 2 million miles, awesome!

 

[Jocko PDX]

Over 2 million miles, awesome!

oops 277K