GhostWriter

According to my notes, the Melling M365HV came with a black & green o-ring. Neither would have worked properly. The Melling pick-up tube came with the red o-ring. Melling's rule sez to use the o-ring that is pre-installed on the pick-up tube, regardless of what is stipulated in the pump instructions. Of course, this means more than one o-ring will work with the pump; but, only one o-ring is ideal for a particular pick-up tube. This means the outside diameter of the rings are about the same. The inside diameter & thickness of the o-rings is what's important. The tube design is what makes all the difference. There are at least three. All of this was verified prior to assembly. As a retired skilled-trades machinist/metrologist, old habits are hard to break.

More than likely, the problem has more to do with a simple installation mistake than anything. The pump this particular individual purchased should work OK. It's just not the best choice for the long term. Seems like problems cropped up, short term. I purchased, in my opinion, the best gerotor pump for my LC9 application. Never mind that I chose to remove all of the AFM components, beforehand. The engine had more than 130,000 miles; so, the M365HV was still the best choice. There's more than one rule that determines the o-ring size. To be safe, decided to invest in a new Melling pick-up tube. The relationship between the pump & pick-up tube is what determines the style of the o-ring. In my case, this meant the stock ring would not be appropriate. Recall there may have been a mention of some engine de-sludge-a-fication. Don't recall whether pick-up tube replacement was mentioned. There weren't many paragraph breaks in the original narrative. May have misunderstood. So, if there's a loss in pressure, where is it coming from? In my case, the unnecessary pan relief valve bore was fitted with a plug. Then, this very simple pump was disassembled to check for defects. No scoring in the pump relief valve bore was observed. After that, the pump was properly shimmed even though many claim this step is unnecessary. No perceived loss in pressure, after re-assembly. There again, I chased, then blew-out every oil passage I could find. By removing the AFM components, these engines become much simpler to troubleshoot, when necessary. That would be my recommendation to anyone who is willing to perform their own wrench work. Want to reduce the variables? Keep things simple.

I usually only log in once or twice a year. You wouldn't want to bet the farm on anything I say, or suggest. Seems like multiple requests for an oil analysis have been suggested. So far, no results have been published. Wow. Consider how many components have already been changed out, per the OP. Then, consider what it takes to properly evaluate the dumbel. Still, no oil analysis. So, we spin a lifter which may, or may not, damage a cam or lifter bore. Then, we replace the components expecting to reclaim an engine in its original condition. There are reasons why some mechanics will not warranty these kinds of engine repairs. You never know, for sure, what's actually lurking in those oil passages. We have testimony that everything seems to go wrong @ around 1500 miles; but, these observations don't seem very scientific, to me. I know what I would do in this case; but, doesn't seem like the OP wants to listen. Good luck.

Just waded through all this. Believe it's very important that we don't continue to confuse the M355 with the 10355. They are two completely different animals. For an AFM application, I would only consider 4 Melling pumps: M365...............standard pressure, standard volume. M365HV..........standard pressure, high volume 10355...............high pressure, standard volume 10355HV..........high pressure, high volume Summit was able to sell a more expensive pump, but it's not the best choice for your application. Standard pressure is more than enough for a stock application. For this application, rule of thumb is to hold out for more volume. Only one clear winner, here: M365HV. If the famous George from Melling was here, I bet he'd back me up. In George speak, thanks for clicking.

Thanks for all the input, and sorry for the late response. Seems like I used to get e-mail notifications when someone answers, but not anymore. Will probably have to move the vehicle about 30 feet to have some laundry room appliances delivered to the basement. Front differential & cv shafts are off the vehicle. Front shaft is resting comfortably on the sway bar. Was just trying to make sure front shaft doesn't try to turn when rolling vehicle while transmission is in neutral. I suspect that it does not, but wasn't completely sure. Sorry for being so cryptic.

I pulled the front differential on the '08 Avalanche recently to make a couple of repairs easier. Will be awhile before the jobs are completed. Doing all the work in the driveway. It occurred to me I may have to re-position the vehicle at some point; but, can't remember if the front driveshaft turns with transmission in neutral, and engine off. Realize it's relatively easy to pull the shaft, but would like to avoid it if it's not necessary. Any thoughts? Thanks.

In my opinion, you're looking for something like the Brian Tooley Torque Cam, designed specifically for trucks. Probably a better choice than any Stage 1,2,3 for your application. As long as your replacement cam doesn't have too much lift, the stock springs will probably perform well, beyond the life of the vehicle. Beehives usually can't make the same claim. Welcome to the world of $400 cams. Look on the bright side. You don't really have to change your factory springs.

So, just trying to make sense of all this. Can understand pulling the motor if a member is unsure of an engine's integrity. Not exactly sure why someone would remove this one, though. Not enough information has been shared. Surely, a buggered hole on one head would not be enough reason to resort to this extreme measure. Hard to believe that anyone who can pull an engine like that would need anyone else's help.

In 4th grade, our cool principal announced the death of JFK. Less than one year later, she allowed for the '64 series to be played in the hallways. To this day, I have appreciated this small gesture that, I believe, helped shape us. She seemed to recognize that our young minds weren't actually healed, yet. Not sure why I'm sharing all this; but, have never been a letter-of-the-law type of individual since. 1000 apologies to the OP. From JFK, to the '64 series, to Bob? Thank's for being patient with me, catching up with myself.

Your question wasn't grumpy enough. We knew it was a rhetorical. What we really want to know is if you are willing to recognize Bob Gibson's greatness?

It's like Colossus said + removing all of the casting sand has never been an exact science. We just pray it doesn't accumulate in an oil passageway.

Thanks for pointing this out. Assuming the L33 would be the best choice if I wanted my LC9 to remain as close to stock as possible after the DOD delete. Another idea would be to upgrade to the Brian Tooley torque cam.

Thanks. Received my Melling oil pump & pickup tube/screen assembly, today. Trying to leave no stone unturned, this time. Thanks, again.

Seems like there's been an issue with lifter quality control & supply, for some time. Am willing to pay a couple of dollars more for something that won't fail prematurely, if necessary. Have had my 5.3 open twice to service a bad AFM lifter. Same thing. The roller goes, but the cam remains pristine. Wonder why? Well, maybe I finally figured it out. In my opinion, the weak point in this whole system is the lifter trays; and, I believe the AFM lifters are harder on the trays than their neighbors in the adjacent cylinders. Amazing how tight the standard roller lifters still fit into the tray, and how loose the AFM lifters seem to be. Not enough to spin, necessarily. Just loose enough to cause damage, perhaps. Anyways, first time in, I neglected to replace the trays. This time, a full DOD delete + new trays. Hoping for better results. Thanks for helping me think it through.