Velislide

FFDP

iTrader: (2)

If the AFM/DoD stuff was replaced with new parts, then technically it should be just fine for a long while. It's once they get a lot of miles on them that problems tend to show up. Yes some get unlucky and things happen while others go 200K+ without a single hiccup as well.

If you want to disable it, you can. A tune can do that. Or you'd have to rip the whole engine apart to replace everything with non DoD parts. So camshaft, lifters, push rods, lifter trays, valley plate etc etc.

My personal opinion about the tuner is that they are garbage when compared to a real tuning program like HP Tuners or EFI Live. That handheld thing can't do anything custom like those other two can. A real tune would be better.

If I was you I'd get a real tuner or tune and re-gear that truck. 35's with likely stock 3.73's is a terrible combo. Makes for a slow truck and worse fuel mileage as the truck has to work harder just to move those heavy *** wheels.

Velislide

Yea, I plan on calling to see what a 4.56 setup will run me. I would like to stick with 35s, and maybe go a little higher to correct the rubbing issue on bumps. As much as I hate body lifts, I might have to consider one just to clear them better. I have the Edge CS2 mounted on the dash, it's nice for the instant fuel mileage, trans temp, and other warnings that I have set to pop up. It's also nice being able to check future codes with it. It came with the truck, so can't complain too much. As easy as I am on the truck, the 3.73s don't bother me too much. But I'm more worried about the stress on the trans and other drive line components.

I don't know what all he replaced, with what either, other then what he told me. But will disabling AFM/DOD with software, help prolong the valvetrain life? What kills them? Is it the constant switching?

swathdiver

The solenoids wear out as will the lifters. However, the newest AFM lifters are much more reliable as is the latest VLOM. See if you can get the part numbers the guy used and asked if the VLOM and the little filter under the oil pressure sending unit was replaced, very important.

The are/were the latest numbers in late 2016 when mine was done:

Updated Rocker Cover - 12642655
Improved De-Ac Lifters - 12645725
Improved VLOM - 12571609
Filter - 12585328

Even though you're not into speed, the tune of the engine and transmission makes the truck more enjoyable to drive and get better mileage usually.

As for gearing, stock 265-70-17 tires with a 3.73 gear mathematically turns 1,925 RPMs @ 70 MPH. With a tire that is 35.13 inches tall and a 4.10 gear, the engine is turning 1,925 RPMS @ 71 MPH. 4.56s at the same RPMs would get you 63 MPH.

Nice looking truck btw!

Velislide

I figured with the increased rotating weight of the bigger wheels and tires, the extra gearing would help a bit, with the 4.56's. Though I called a place in town yesterday, and they quoted me 2500$, possibly more depending on the condition of bearings and what not in the diffs. Seems a little high to me? I have no idea, never had a truck regeared before.

I would say a majority of my driving will be short distance, in town driving. So as far as stressing the transmission the least possible, would 4.56 be better for that? I might just try and do the regear myself. I'm pretty decent at figuring things out. Have done top ends on Duramax's, engine swaps, and what not. If directions are out there, I'm sure I can follow them. Thanks for the info though, it's nice having some insight, these gen motors are totally new to me.

swathdiver

Well, a 4.56 gear would have you turning about 200 rpms more at 70 mph. So you have to ask yourself if the additional rpms are going to stress the transmission more or less? You can get a subscription to the shop manual for your truck over at AllDataDIY and or buy it from SeriousCTBuyer on ebay in .pdf form. I like having both.

Velislide

I also talked to the previous owner that replaced the lifters, he said what he knew was that he replaced it with the ones that supposedly "fix" the issue, so guessing the updated ones. Though I asked him about the VLOM, and he said he didn't replace anything with that. I didn't even know what it was when asking, but now I have a pretty good idea of what it does. Going to ask him if he cleaned it up at all and cleaned the screen filters out, in the morning. Now if he did that, should I be okay for awhile? Or would it be wise to just order the new VLOM plate & solenoids off Amazon (220$), and install that? Guessing all I really have to do is pull the intake manifold off, replace VLOM plate, reinstall manifold?

Reading up on all this AFM and VLOM crap has me pretty worried now. Truck runs great, no knocks or ticks, pulled oil cap to listen and doesn't sound any different then with it on. When hot, 25-28 PSI oil pressure at idle, at the lowest. He said he never touched the filter screen under the pressure sending unit, either. Any suggestions? Am I over thinking this? Or is it just a matter of time before the new lifters fail, without changing the VLOM?

swathdiver

It's hard to say. Some systems fail at 20k miles while others go 300k miles. It usually boils down to maintenance and clean oil. My original system went out at 110k. My BB tune disabled it. Parts are still there but am not worried. These are same lifters used in new Gen V motors and they are very reliable. It would be good piece of mind to install new VLOM and the little $6 filter. It too is much more reliable. Or you could plan to delete the whole thing as many do. Not sure how often it would run in V4 with those tires on it. Do you?

3wide

You are calculating this out correctly don't worry..! Too many people when it comes to gearing get caught in RPM when it comes to large tires & towing. Gearing is being able to take the Engine Torque and multiple it to get you the most effective power to the tire.

It's more like how much torque do I want to my tires, and how much throttle pressure will it take to hold a certain rpm for simplicity sake:

Let's say 300lbs of torque for a 5.3engine for numbers sake. 300*.70 (OD) * 4.11 (final drive)= 863 lbs of torque to the wheels. 4.56 (final drive)= 957 lbs of torque to the wheels.See the increase.? This is were Manufactures increase tow ratings of a vehicle by just changing the gear ratio. It how has nothing to do with RPM at a given MPH but by how much torque can be applied to the tires to pull a certain load or over come more rotating mass (tires).

Velislide

I'm actually thinking of going down to 34's, and OEM Silverado 18" wheels off the new Z71s. Just a thought, nothing decided yet. So if I did that, 4.10s would probably be fine. I won't stress anymore about the VLOM for now, I'll just plan on changing that plate at some point. Not really looking to tear into the engine and replace the lifters again, the cam, and everything. I can disable the DOD with my Edge CS2 from what I hear.