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Hi. Purchased a 2019 XL 5.3. It’s got about 50k miles. Last weekend I changed all the fluids. Drove it today and when idling the oil pressure dropped to a hair below 30. Normal? I’ve never had a vehicle drop like that when idling. Also when idling every 10 seconds or so I feel a very light movement. Normal? Everything sounds fine and drives good. Not sure what to make of this. Any information helps. Exactly 8 quarts added during the oil change. Thank you.
 

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‘01 Silverado 2500HD 8.1/Allison 5sp xcab long bed
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30 at idle is fine. As for the other thing, do you notice the tachometer moving when it happens?
 

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20 at idle meets GM spec.
I suspect what you feel is the computer disabling cylinders, it's called DFM
 

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Discussion Starter · #4 ·
Thank you Greg and Rey for the response. I appreciate it. Took a drive today to monitor the gauges. Idles at 30. Normal cruising sits at about 40. Will let it be and not think much of it.

As for the slight movement I feel every 7 ish seconds when sitting idle. The tachometer does not fluctuate. Maybe just a normal mechanical function/movement?
 

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The engine will idle at the same speed, just some of the cylinders will be de-activating.
 

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Your right, the 2012 5.3 (gen 4) needs 6 qts; however, the 2019 (gen 5) needs 8 qts.
 

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Yep, more oil but it's making more power at 355hp and 383 ft-lbs torque on a 5.3L.
My 2001 only has 285hp I think.
The 2018 tows better but not sure how tough is the 6 speed tranny.
 

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I seems to be plenty tough, my 6 speed has towed a bit; but my buddy uses his a lot, pulling a 36 ft car hauler.
 

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I hope so Ray.
You know, there is no direct 1:1 drive on the 6 speed 6L80.
4th gear is almost a direct at 1.152.
5th gear is an overdrive at 0.852
6th gear is at 0.667.
If you tow in tow/haul mode, most of the time it's going to be in 5th and 4th on inclines and 6th on downhills.
I hope the 4-5-6 driving clutches are strong enough to last as long as my 4L60e now at 288k miles.
But we will see.
I tow a 5k pound camper.
 

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The car hauler 3 of us take turns hauling is around 5500.
I use the manual shift and keep it in 4 most of the time; but my buddy with the 1500 just uses D and let's the computer pick the gear. The 2 trucks both have 5.3s and the 6 speed. The 3rd truck is a 2500 with the 6.0 and the 6 speed; but it may be the 6L90.
 

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Yes, I used to tow in L5 back when I didn't have a Range AFM disabler.
With the Range AFM disabler, it's now always in V8 so I just put it in D and engage the tow/haul mode.
Good to know.
How many miles now on the 5.3L?

Sorry for hijacking the thread OP.
 

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I've got about 160 on my 5.3, I don't know what's on the other one.
 
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