Friday was maintenance day on the 2005 Tahoe

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Been driving around this 2005 Tahoe for the past month or so.

Body has 286k, engine has about 150k (swapped in a 4.8 I had sitting years back for the 231k 5.3 that was tired), trans has about 100k.

Went through the trans, front and rear diffs and transfer case. Trans got a new ACDeclo filter and fill of Mobil Delvac 1 ATF (TES-295) spec. Transfer case got AutoTrak II, front and rear diffs got Mobil Delvac 1 75W-90.

The front diff was pretty gross, dirty old fluid and metal on the plug. The rear diff was dirty, some metal, but the teeth on the ring gear looked real good. Transfer case looked pretty clean -- it had been done a month prior and was dirty. But good to see this time it was clean still.

Trans looked like 100k fluid. The 4L60e seems to really like the TES-295. Shifts are just as confident as before, overall seems to shift smoother and quicker.

Overall drivetrain in the truck seems more free and quieter. I am pleased. Think I am going to buy this off my Dad and keep it around for a while. With the way the used market is, and already knowing it's history and what is good/wrong with it, seems like a much more solid choice than buying something uknown. Plus Dad don't want a lot and will get a vehicle out of his yard.

I figured it out -- for me driving about 400 miles a week, it would take $9 per gallon gas to be at a point where a $400 car payment per month with a new vehicle obtaining 30mpg would be cheaper to drive than paying for fuel costs on a 15-16 MPG GM truck. Additionally, the $400 car payment might even be on the low end as I like the finer things in life, good stereo, leather, sunroof. So unfortunately a $200/mo. car would never be a thought for me. Tahoe is an old girl but the Bose still sounds good, leather heated seats and at the end of the day its a truck that can tow.

Overall I am very pleased and happy.
 
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Redhat, How did the trans pan look when you changed the fluid? As long as you did not see any big chunks of clutch material, metal bits you are probably good to go for at least another 50k with that trans. The usual fine bits of clutch material filings don"t count.....that is just normal wear as they say.
 

redhat

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Redhat, How did the trans pan look when you changed the fluid? As long as you did not see any big chunks of clutch material, metal bits you are probably good to go for at least another 50k with that trans. The usual fine bits of clutch material filings don"t count.....that is just normal wear as they say.
It looked great, nothing in the bottom of the pan. Fluid was still red, a bit dark. There was the usual stuff on the magnet.

Why'd you do the transfer case twice in a month?
Well, when I changed it last, it was pretty yucky, dark and probably in there for a long time. So I figured I'd change it once more to flush it out.

Is the 4.8 a direct replacement for the 5.3? How does it run being such a small engine in a heavy truck?
No not really, but kinda-ish? GM did offer the 4.8 in the Tahoe in 2WD offerings. 4.8 and the 5.3 are the same block... 4.8/5.3/6.0 have all the same dimensions so it did bolt right in. 4.8 has flat top pistons and a longer stroke than a 5.3. All in all, it runs just as good as the 5.3 does. It idles fine and seems alright on power. I am sure however, that a 5.3 would feel much more powerful. I never daily drove this truck until recent so I cannot speak as to how the 5.3 was. Also, this 4.8 may very well has about the "same-ish" power as the old 5.3 did when it was tired with 231k on the clock.

I never tuned the PCM after the 4.8 swap. I had all intents to, however the local tuners I contacted would never get back to me. Since it idled fine, seemed to run fine, didn't set any CELs and there didn't seem to be any excess gas smell in the oil, I left it alone and figured that the 4.8 is just small enough compared to a 5.3 that the PCM is trimming excess fuel out based upon the O2 sensor readings.

Who knows thought? I am not a tuner just a backyard Joe Blow who does his own tinkering. I guess I would be interested if the correct tune or a better calibration on this thing would net any differences an or if I am leaving anything "on the table" with it's current state.
 
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I’ve said this before, but the 4.8 is a dog in the Tahoe. GM used the 4.8 in the Tahoe for a few years so they could claim 20mpg highway. Good luck getting that though. Yeah, it makes good power numbers higher in the RPM band, but you sacrifice MPG, when the 5.3 makes better power numbers at lower RPM using less fuel. Realistically the 5.3 was better at performance and MPG. From 2007-2013 the only advantage the 4.8 had over the 5.3 was it didn’t have AFM. Id take a slight power dump and questionable MPG to avoid the 5.3 issues of that era. The sweet spot for the 4.8 may have been 2011+ since that is when it was given VVT with more power.

Rental agencies stocked plenty of the 4.8 Tahoes back in the day, fully loaded with passengers they were anciently slow.
 
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It looked great, nothing in the bottom of the pan. Fluid was still red, a bit dark. There was the usual stuff on the magnet.


Well, when I changed it last, it was pretty yucky, dark and probably in there for a long time. So I figured I'd change it once more to flush it out.


No not really, but kinda-ish? GM did offer the 4.8 in the Tahoe in 2WD offerings. 4.8 and the 5.3 are the same block... 4.8/5.3/6.0 have all the same dimensions so it did bolt right in. 4.8 has flat top pistons and a longer stroke than a 5.3. All in all, it runs just as good as the 5.3 does. It idles fine and seems alright on power. I am sure however, that a 5.3 would feel much more powerful. I never daily drove this truck until recent so I cannot speak as to how the 5.3 was. Also, this 4.8 may very well has about the "same-ish" power as the old 5.3 did when it was tired with 231k on the clock.

I never tuned the PCM after the 4.8 swap. I had all intents to, however the local tuners I contacted would never get back to me. Since it idled fine, seemed to run fine, didn't set any CELs and there didn't seem to be any excess gas smell in the oil, I left it alone and figured that the 4.8 is just small enough compared to a 5.3 that the PCM is trimming excess fuel out based upon the O2 sensor readings.

Who knows thought? I am not a tuner just a backyard Joe Blow who does his own tinkering. I guess I would be interested if the correct tune or a better calibration on this thing would net any differences an or if I am leaving anything "on the table" with it's current state.
When I met my wife she had an 04 Tahoe with the 5.3. thing was a rocket considering how heavy it was. It had a towing package with something like 3.42 gears which helped it a lot I'm sure.
 

redhat

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Do you have HP-Tuners? I have a 2005 4.8L Tahoe calibration file if you need it. You can spend the money you were going to give a "tuner" & buy your own HP-Tuners & I'll walk you through doing a 4.8L Segment Swap.
That would be awesome, I'd appreciate that tons! Good buddy of mine has an MVPI2 and HPTuners on a Surface tablet. I'd be more than happy to get credits and get the right config on this thing.
 
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I need the Operating System part number out of your PCM to make sure that the calibration file I send you is compatible, Trying to patch Segments from different/incompatible OS's can "brick" the PCM.

Read & Save the calibration file from your PCM.
*I recommend reading & saving it a second time & naming it something different, This will be your back-up/recovery file if something goes sideways.....Not that it's common to have issues with P59 controllers even though HP-Tuners warns you that these are "brickable" when rewriting the entire file., And YES....You must "Write Entire" for Segment Swaps to take!

Open the first file you saved, Click on the "Calibration Details" icon (Red Arrow), Then you can read the Operating System part# (Underlined)

x93ExeB.png
 

redhat

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I need the Operating System part number out of your PCM to make sure that the calibration file I send you is compatible, Trying to patch Segments from different/incompatible OS's can "brick" the PCM.

Read & Save the calibration file from your PCM.
*I recommend reading & saving it a second time & naming it something different, This will be your back-up/recovery file if something goes sideways.....Not that it's common to have issues with P59 controllers even though HP-Tuners warns you that these are "brickable" when rewriting the entire file., And YES....You must "Write Entire" for Segment Swaps to take!

Open the first file you saved, Click on the "Calibration Details" icon (Red Arrow), Then you can read the Operating System part# (Underlined)

x93ExeB.png
Just pulled a file. Yes, this PCM has the same OS number as you posted above.
 

redhat

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I’m guessing by the OP’s username he may be very adept at pushing firmware around. ;)
Haha might have done it a time or two :sneaky:.

I have done quite a bit of BCM/Ford Module editing with Forscan on Taurus and many F-150s. Adjusting many different IPC settings and BCM options. I have toyed a bit with GM SPS (Techline Connect) for module programming - ATC on the Suburban and a window control module on GMT900. Also Tech2Win was pretty helpful in diagnosing airbag codes on Dad's 2004 LeSabre.

Oddly enough I also got into BMW INPA and module coding with a 2007 335xi. The hardest part was figuring out the German as I don't speak it. Very interesting with them where you write values/changes to a file with a text editor then upload it.

For HPt, good buddy of mine bought a MPVI2 for turning off AFM on his Tahoe and for a never-ending, quest of GM vehicles and project car/motor swaps. The 5.3 in his Tahoe ended up dropping a lifter, so he swapped in a LY6 with an LS3 cam.

I am by no means a auto-tech/cal/tuner/programmer pro. But what has helped me is that I am an IT professional. A lot of times the technical aptitude can carry over. So I can 99.9% guarantee the computer/software is setup appropriately to communicate with the module/dongle/serial cable. What comes to mind is the BMW requires you to manually specify serial parameters and baud rate.
 
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I’m guessing by the OP’s username he may be very adept at pushing firmware around. ;)
And you know what - cars these days are running RTOSes with elements of Linux/Unix these days - be it Wind River VxWorks, Green Hills Integrity or others for the PCM and other critical modules. And even Linux or Android for infotainment.
 
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