2015 Suburban Problem Child

[L8T BURB]

Hello to all! I purchased a 2015 Suburban about 6 weeks ago. First time owning one, and I fell in love during the test drive. It's got quite a lot of miles, 186k to be exact. It's 2WD, which was actually appealing to me as well, as the weather here rarely warrants a 4WD. Paid $17,500. Pics below of first day of ownership and now current status.

I did a couple of cosmetic upgrades with a set of 2021 Suburban rims, 5% window tint. Then some mechanical stuff, new water pump, thermostat, front wheel bearings, rear brake pads, shark fin antenna, rear lift gate struts and drivers door lock switch. Just in 1 months time, this feels like a lot, but then again, I did purchase an 8 year old vehicle with nearly 200k miles. So...par for the course?

Now for the bigger stuff...

I've developed quite the lifter tick in bank 2. I've noticed it only ticks when the AFM system switches to V8 mode. Either way...I know I'm due for a full AFM delete.

Additionally, after some heavily spirited driving in attempt to "unstick the lifter", I realized I've got some fairly significant transmission issues. Under WOT, it will stumble greatly for a couple seconds before finally revving out like it should. When cruising around 30 mph, the motor seems to be facing some resistance as it sits around 1800-2000 RPM which doesn't seem reasonable for that speed on flat ground.

With all that said, current plan is a full AFM delete. Complete with non-AFM cam, LS7 lifters, valve springs, push Rods, oil pump, etc. As for the transmission, I feel like I may as well budget for a reman unit. Feeling like I'm on borrowed time regardless given the mileage of this rig. So I am thinking a GM reman transmission with an upgraded billet torque converter from Florida TC.

I hate that I am experiencing so many issues right away on this one, but I'm looking more long term and thinking that after the motor and transmission repairs, I (should) be set for a while. I'd like to drive this until at least 300k miles. If I was to trade or sell, I'd take around a $5500 hit, so I plan to roll that "theory" money into these repairs.

Any insight from you all? Anything I should be considering that I haven't already mentioned? Up to this point, I have performed all repairs needed, however I will be outsourcing the engine and transmission work as I have 4 kids that keep me plenty busy, and do not have the time, patience, and to an extent, confidence to carry out the engine and trans work.

Thanks all!

 

[tom3]

For the driving issues I'd put it in low range and switch up to 5th (?) gear and drive it some in full V8 mode. See if this makes a difference. Really a good looking machine and sure worth the expense I'm thinking.

 

[wjburken]

I've developed quite the lifter tick in bank 2. I've noticed it only ticks when the AFM system switches to V8 mode. Either way...I know I'm due for a full AFM delete.

Additionally, after some heavily spirited driving in attempt to "unstick the lifter", I realized I've got some fairly significant transmission issues.

I’m afraid that your lifter likely isn’t stuck, it’s likely collapsed and not fully extending in V-8 mode. Hammering it will likely make it worse.

I’d be looking into that AFM delete sooner rather than later before the lifter completely leaves the chat and possibly grenades itself.

 

[NickTransmissions]

@interceptor859 - Nice looking Burban, congrats on the purchase. And agree w/you with respect to the transmission. I'd also make sure the dealer or trans shop installs an updated GM cooler bypass valve to ensure trans temps run cooler after you have the trans rebuilt or replaced.

If you go w/a reman, I'd also recommend having a GM unit installed - I believe they are 3 year/36,000 and should have all the requisite updates that these things need based on various design flaws and associated pattern failures noted over the years.

I have a ton of info in my 6L80 Info thread (see my sig for the link) - LMK if you have any trans questions.

 

[gapost]

I just put a GM reman trans in my 19 Tahoe with 122k. I got the upgrade TC from FL TC and it's driving great. Already had the modified thermal bypass. Just a small thing, change your O2 sensors when the exhaust is pulled out for the transmission.

 

[L8T BURB]

I’m afraid that your lifter likely isn’t stuck, it’s likely collapsed and not fully extending in V-8 mode. Hammering it will likely make it worse.

I’d be looking into that AFM delete sooner rather than later before the lifter completely leaves the chat and possibly grenades itself.

UPDATE!

The lifter did in fact leave the chat lol! I was driving to work and as I was pulling into the parking lot, I started to get a very noticeable misfire. I limped it home, scanned and it showed a cylinder 4 misfire. Same bank and location where the lifter sound was coming from.

I drove it to my mechanics garage, roughly 15 miles from my house. The vehicle was running ROUGH! Flashing engine light, whole vehicle shaking, some black smoke coming from the back, and also a faint sound that was RPM dependant which sounded like metal on metal screeching. My oil pressure also was reading VERY high during this, around 70 PSI.

Its at the shop now, awaiting what will likely be a full engine rebuild to include the AFM hard delete. The mechanic is also going to diagnose the transmission, which I am sure will unveil that I am in need of a full trans replacement. I've also got the front and rear shocks, outer tie rods, upper control arms, lower ball joints, spark plugs, wires, both belts, belt tensioner all on the list of parts to replace.

Additionally I am having the 3rd cat deleted, along with the resonator, and replacing the stock muffler with a flowmaster 40 series. I know flowmaster isn't held in high regard here, but I have used the 40 series on several other vehicles in the past and really enjoy the sound.

Hopefully this thing will give me several years of trouble free driving after this likely $10k repair bill.