Learn me: GM 5.3L/6L80

So, I may of agreed to purchase a 2010 Tahoe PPV from a local dude today. It was a K9 unit and has 149k miles on the clock. It's in good shape and runs fantastic.

Other than that, I don't know berk about GM powertrains. I know the 2010 and up got the 6L80 transmission and that's it's a 5.3L. Is the AFM really that crappy? It seems pretty simple to disable it.

Is there any inherent weaknesses that I should address immediately? The seller has every single service record from when the police dept purchased the truck. It's been very well maintained. Any time bombs I should be aware of?

The afm is irritating to drive with, I think, and it's one of the two ways that engine causes trouble.  The other is worn cam lobes, and the chances of both can be dramatically lessened by changing better oil more often.

I'd disable the afm, myself.

Those are the best looking Tahoe's IMHO.

In reply to Streetwiseguy :

The seller showed me the huge stack of maintenance records when I looked at the truck today. I'm hopeful it got regular oil changes but I'm definitely going to change the oil once it's in my possession.

I'm definitely going to disable the AFM. I've found lots of horror stories on the net about excessive oil consumption and cam wear. Its not worth it to me. 

dxman92 said:

Those are the best looking Tahoe's IMHO.

I agree and I'm not a GM fan at all. In fact, this is my first GM product after nearly 41 years on this earth.

It's going to need new headlights and I've already found a used pushbar for $200. Oh and a $130 SLP resonator delete kit (because V8 noises ).

I'll be keeping the police spec wheels because steelies are awesome but the tires have maybe 30% tread life left.

I forgot to check the idle hours while I was there because I didn't realize it had a spotlight until I saw it in person aaaaand I got distracted. 

But I'm happy to report that the spotlight is fully functional 

I was looking into these awhile back and learned that there's a small screen filter for the AFM/lifters in the valley. These are almost never cleaned or replaced. I've never touched an AFM engine, but this seems like something that probably contributes to a lot of the AFM failures and problems that you hear about.

Change the oil frequently and I'd replace that filter at least every 50k and you're less likely to run into AFM problems.

STM317 said:

I was looking into these awhile back and learned that there's a small screen filter for the AFM/lifters in the valley. These are almost never cleaned or replaced. I've never touched an AFM engine, but this seems like something that probably contributes to a lot of the AFM failures and problems that you hear about.

Change the oil frequently and I'd replace that filter at least every 50k and you're less likely to run into AFM problems.

The screen is changed every time the intake manifold comes off to remove the oil pressure sender because the screen gets plugged up.

The plugging screen is a symptom of infrequent oil changes, or using cheap oil.

stanger_mussle (Supported by GRM undergarments) said:

In reply to Streetwiseguy :

The seller showed me the huge stack of maintenance records when I looked at the truck today. I'm hopeful it got regular oil changes but I'm definitely going to change the oil once it's in my possession.

I'm definitely going to disable the AFM. I've found lots of horror stories on the net about excessive oil consumption and cam wear. Its not worth it to me. 

Are those records from a civilian shop, or something internal through the state/county/township where the truck came from?  I know in my immediate area the FHP goes to PepBoys for all their work.  Usually with fleet work that equates to cheap oil, but done regularly. 

From my limited experience, cops are also unnecessarily hard on vehicles.

If its a solid deal, grab it.  I'd just focus on flipping through the records and seeing what was actually done and when 

Mr_Asa said:

stanger_mussle (Supported by GRM undergarments) said:

In reply to Streetwiseguy :

The seller showed me the huge stack of maintenance records when I looked at the truck today. I'm hopeful it got regular oil changes but I'm definitely going to change the oil once it's in my possession.

I'm definitely going to disable the AFM. I've found lots of horror stories on the net about excessive oil consumption and cam wear. Its not worth it to me. 

Are those records from a civilian shop, or something internal through the state/county/township where the truck came from?  I know in my immediate area the FHP goes to PepBoys for all their work.  Usually with fleet work that equates to cheap oil, but done regularly. 

From my limited experience, cops are also unnecessarily hard on vehicles.

If its a solid deal, grab it.  I'd just focus on flipping through the records and seeing what was actually done and when 

You bring up a good point. I don't know if it was maintained by the department or farmed out. I plan on going over the records to see the maintenance history and where the work was performed.

Since this was a K9 unit vehicle, I'm sure it spent a lot of time idling with the a/c on. The rear HVAC controls for the dog kennel are still installed.

I would walk away from it if that 6L80 hasn't had a fluid change and filter documented.  They are more stout than the 4l60 but go downhill very fast when neglected.

In reply to RacetruckRon :

Finally got the truck home and had a chance to look through all the maintenance records. The transmission fluid and filter was changed as part of the 100k service. The truck has 149k miles on it now. Also of note; lots of brake, wheel and tire replacements. I guess it makes sense since this was a patrol vehicle.

I forgot to add that all the maintenance work except for recalls were performed at the sheriff office's vehicle maintenance shop. The recalls were performed at the local Chevy dealer.