asilverblazer

Everything's always easier the second time!

I apologize, I missed this post, at risk of going off CURRENT TOPIC. I'm not saying it is BS, I'm questioning how much information is being held back. GM is NOT going to spell out exactly every parameter in the algorithm. Liability, intellectual property, etc. I'm not naive enough to believe that it is as simple as revolutions, coolant temperature, miles, time; are you? I don't do irrational either, and boiling the OLM down to four simple values that I could code in an afternoon (I'm not a coder) is irrational - unless it suits your agenda to ignore it.

I've had good experience with my Android head unit.

You should be evaluating enough comparable trucks to know if one sounds different than the others - if you can't tell something is amiss by ear, it's probably fine. Further evaluate enough trucks so that you can determine what 'normal' looks, sounds and feels like. Even if this is the first truck you're looking at and want to buy, go look at several more (regardless of whether you intend to buy them). Insist on taking the vehicle to be evaluated, spend some time looking ALL OVER IT, look for overspray where it shouldn't be, paint damaged on bolt heads that are not normally removed. Check for rust, missing fasteners, non-factory style fasteners, suspiciously new parts especially on non-wear items. Check for leaks, check fluid conditions and level (dirty isn't the worst thing in the world but exceptionally low is). Ignore tire shine and plastic dressing that makes an engine 'shiny'. Beware of heavily fragranced interiors to mask odd odors that could hide potential mold from a leaky rear window. Carfax is barely worth the paper it printed on. DO NOT trust it, a vehicle can be wrecked, fixed by a bunch of drunk hillbillies in their cousin's backyard and still have a clean Carfax. I can meticulously maintain my vehicle at home with top quality parts, materials and methods, the Carfax won't show a thing. Taking it to a shop to have a teenager working afterschool (an inexperienced mechanic) evaluate it is a waste of time. Lastly, a good, well taken care of truck will present itself as such, it would be generally comparable to a new truck. An uncared-for truck will show it, dents, scratches, seat stains, paint swirls, tears, scuffs, marks, rattles, vibrations, clunks, miss matched tires, etc...

If you suspect an engine swap or similar modification to the front accessory drive... Maybe try spending some time plugging in different make/models/years that utilized the same engine (prime donor vehicles or swap candidates), vans, full-size cars (Impala, Roadmaster), 4x4 trucks to get a collection of pump and brackets that are similar along with their associated part numbers; take that collection of part numbers to the parts store to compare. Another Okie.

Topic: OCI, not when but why? Have you considered that just because there is limited documentation on GM's programming of the OLM system that it is not a sign of it's simplicity but a protection of intellectual property? We both agree the system's published parameters are too limited to present an accurate picture of oil quality. I am not discussing my oil change routines in this comment, I am discussing the parameters of the GM OLM; a key component of "OCI" when and why. You know what I find interesting? GM trucks, discussing things relevant to those trucks. If free conversations are not allowed in threads you start I suggest having a discussion with a moderator to have them grant you authority to police and suppress the free exchange of thoughts on your topics accordingly. Alternatively, if you only want to talk about oil without distractions I suggest bobistheoilguy.com or starting your own blog. Carry on your discussion of "Engine Wear and ISO 4406"

I know the system does not sample the oil, though I would expect slightly more sophisticated algorithms than what you posted or what I found in 18-NA-125. The coolant temperature readings and how it alters the oil life are probably the least understood in the algorithm. Nothing definitive is published regarding how those temperatures are used that I can find beyond the bulletin I referenced. Also, I agree with the disconnect between coolant temperature and oil temperature. Maybe they aren't concerned with oil temperature (directly) or can extrapolate what the oil temperature should be based on coolant and ambient temperature... all speculation on my part how they are using coolant temperature to 'degrade' oil life, I doubt it to be a simple calculation. I found lots of suggestions that it monitors/uses other parameters, including oil temperature directly, as well as someone saying injector pulse width has a heavy hand in the algorithm. I KNOW a bunch more schooling, time and money than what I have has been spent on the OLM than what I ever could, to end up at a maximum OCI of 7500 miles.

I agree. However, the owner's manual, suggests that a drop over full is just as bad as a drop under. (Read black and white letters only, insert no common sense.)

That P0700 and loss of power suggests something significant is amiss to me. More/other codes may suggest otherwise; I would investigate those prior to spending the money to change fluid on a transmission with a bad torque converter. The relatively sudden escalation of symptoms to me suggests that something began failing (initial shuddering experienced) and rapidly deteriorated (slipping/loss of power). Fluid condition alone wouldn't cause the sudden escalation of problems - though it might have been the cause of the deterioration up to the point of failure.

Stabilitrack operation is in a sense a separate/independent operation from the operation of 'traction control'. Stabilitrack is used to keep the vehicle traveling in the DIRECTION intended, it can brake independent wheels and or adjust throttle to influence the direction the vehicle is moving. This can be illustrated by a 'fish-tailing' example. At high speeds, if the stabilitrack detects excessive yaw (the vehicle spinning like a top, it has a sensor for this), based on inputs from steering angle it determines that the vehicle is spinning out of control, and begins working to control that unintended spin. By reducing throttle input or braking specific wheels to control or prevent the spin. The traction control works similarly using the ABS system to slow spinning wheels and thus transfer power to 'other' wheels. The goal being to achieve wheel speeds that are all in agreement with each other, the truck then assumes that since all the wheels speeds are the same no spinning is occurring. For example, launching up a wet boat ramp, there is no excessive yaw present, traction control alone can manage the wheel spin by braking spinning wheels and cutting throttle. Stabilitrack and traction control from a hardware and software standpoint are basically one in the same, I don't remember specifically in 2004, but you couldn't get a truck with one and not the other. The switch on the dash, could turn off the traction control, but not necessarily the stabilitrack. A confusing comment about stabilitrack vs. traction control, the same components serve both operations, but marketing could advertise them as two separate features. The AWD system is another separate system entirely, in addition to the other two, it uses the same wheel speed inputs but can also vary the transfer case clutch application to direct some power to the front axle, working in conjunction with the traction control to bring wheel speeds together. The power split will never be greater than 50:50, the same as 4-high. It will never direct MORE power to the front axle than the rear.

The GM oil life monitor 'should' be able to account for these conditions in determining the OCI. My driving habits and environment allow the oil life monitor to trend to the maximum end of it's programming, I think most are programmed to max out at 7500 miles.

This is sort of my point, salvage yards aren't overflowing with all these 'poorly' maintained trucks - excellent/good/servicable condition otherwise, salvaged only as a result of a bad engine from poor oil change regiment. In my area, there are no 2007 to newer gm trucks/suvs in any salvage yards. A few are in the 'recyclers' with very obvious reasons for being there - wrecked.

Stabilitrack was a stability control, traction control system, that functioned independently from the transfer case. Z-71 has nothing to do with the transfer case or differential. If it does have an AWD system, my memory recalls this being specific to the Denali trim, converting won't be as simple as swapping out mechanical parts like differentials and transfer cases. It will require reprogramming at a minimum. Long story short, not likely worth it. Pulling a fuse, may disable the AWD system, it might also prevent any other transfer case functions. However, the AWD case was generally based on the same transfer case you refer to in the 2006 Suburban. If it still has a 4-High and 4-Low where the transfer case locks and splits power 50-50 front to rear, what are you gaining by changing anything? A true-rear wheel drive only, what good will that serve? Not enough to go through the trouble of changing out all the parts. Generally, all the factory systems will handle a 33" tire and re-gearing. Probably a 35" tire too, if you aren't driving like a caveman. If 35" tires are in the plan... If you do plan on driving like a caveman or are fully committed to 35" tires, an entire re-think of the build is probably in order. Starting with square one, an IFS front end isn't going to be the best starting point for 35's and caveman driving.

I think it failed, new fluid isn't going to fix it.

The booster probably failed internally. (Applying the brakes is basically creating a vacuum leak.)