GM 2007 - forward 5.3 discussion
- Thread starter mjk1967
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I don't trust the 6L80e behind any of them.
the majority of 5,3 have the 4l60e which is weaker than 6l80 . any 5.3 before 2008 is a safe bet. best engine i have ever owned by a lot
In late 2011 the changes there were changes made to make the motor less trouble prone as far as lifters are concerned in regards to AFM. In 2019 GM installed DFM and some 2019's were problematic. Also the 8 speeds were problematic as well. The 2022s are far better. The 6I80 is a sloppy but reliable transmission. Yes-there are some torque converter issues-but those are usually high mile trucks. To review-skip 2007 through early 2011-and 2019 and 2020s. I happen to own a 2018-and think this is the "best bet".
There is a cooler transmission thermostat made by the after market as well as GM that can be installed to help the transmission run cooler. If a truck is still covered by a power train warranty-this part can be installed at the dealer without charge. There is a TSB on it. It's also an easy DIY.
Unlike some who are non-owners who will ultimately comment-I have owned three of these trucks.
You will be hard pressed to find a truck not priced at a premium in this market. You will spend a better part of 50 grand for a newer truck without mega miles.
A visual inspection will not gain insight to any potential AFM issues.
There is a cooler transmission thermostat made by the after market as well as GM that can be installed to help the transmission run cooler. If a truck is still covered by a power train warranty-this part can be installed at the dealer without charge. There is a TSB on it. It's also an easy DIY.
Unlike some who are non-owners who will ultimately comment-I have owned three of these trucks.
You will be hard pressed to find a truck not priced at a premium in this market. You will spend a better part of 50 grand for a newer truck without mega miles.
A visual inspection will not gain insight to any potential AFM issues.
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I don't "trust" any AFM engine past 200,000 miles, The locking mechanism in the AFM Lifters wear causing them to stick in the collapsed position. This is the one failure mode that WILL happen eventually. Though I've had pretty good luck "Unlocking" collapsed lifters & disabling the AFM via tuning software.
Lifter Roller/Cam "Spalling" & Lifter Guide failures allowing the lifter/s to rotate can happen to any LSx engine. Though I'd say these failure modes are rare.
6L80E torque converter failures are less frequent in the GMT900 platform because the calibration differences between it & the K2XX platform.
The K2XX platform has serious issues with converter clutch failures after @ 100,000 miles. The Thermostat Bypass Mod is great & all.....But it WILL NOT prevent a converter failure, Like a bandaid on a GSW in my opinion.
Had a 76,000 mile 2017 K2XX Silverado in this past week with intermediate TCC Shudder. I first put a "No TCC Slip" custom calibration in the TCM along with disabling the AFM.
Completely cured the shudder sensation, However.....Quick throttle tip-in would cause spikes in TCC Slip. I maxed out TCC Pressure just to see what would happen, It didn't help.
Installed a twin disc Billet Front Converter along with a couple TransGo kits in the Valve Body, Fluid & Filter, & TransGo Thermostat Bypass kit.
Cleared the adaptives, Performed a quick learn, Then performed a couple thorough test drives.....It's like a totally different unit!
A lot of the clunkiness in K2XX 6L80E's is from the TCC being applied in lower gears for the sake of MPG. Calibrate it to apply only in 4th-5th-6th or 5th & 6th goes a long way!
Lifter Roller/Cam "Spalling" & Lifter Guide failures allowing the lifter/s to rotate can happen to any LSx engine. Though I'd say these failure modes are rare.
6L80E torque converter failures are less frequent in the GMT900 platform because the calibration differences between it & the K2XX platform.
The K2XX platform has serious issues with converter clutch failures after @ 100,000 miles. The Thermostat Bypass Mod is great & all.....But it WILL NOT prevent a converter failure, Like a bandaid on a GSW in my opinion.
Had a 76,000 mile 2017 K2XX Silverado in this past week with intermediate TCC Shudder. I first put a "No TCC Slip" custom calibration in the TCM along with disabling the AFM.
Completely cured the shudder sensation, However.....Quick throttle tip-in would cause spikes in TCC Slip. I maxed out TCC Pressure just to see what would happen, It didn't help.
Installed a twin disc Billet Front Converter along with a couple TransGo kits in the Valve Body, Fluid & Filter, & TransGo Thermostat Bypass kit.
Cleared the adaptives, Performed a quick learn, Then performed a couple thorough test drives.....It's like a totally different unit!
A lot of the clunkiness in K2XX 6L80E's is from the TCC being applied in lower gears for the sake of MPG. Calibrate it to apply only in 4th-5th-6th or 5th & 6th goes a long way!
Buy a GMT-800 GM truck and don't worry about a thing outside of regular maintenence. Squirt grease where needed. Plug in a new battery as needed. Drop and fill engine and transmission as needed. Fill it with quality fuel.
Zero worries. ;>
Zero worries. ;>
Buy a 07 or 08 Yukon Denali w/6.2L. They didn't have AFM/DOD.
As always, your insight and professionalism are greatly appreciated.
Yes there are a few 11 and 12 Yukons in my area with the 6.2. Kind of where I was looking,, price-wise
The 6l80 was worse than the 4l60 in practice. But yes that gen 3 platform was invincible. My 209k 5.3 and 322k 6.0, and both 4 speeds have all original internals inside and i do extended oci's on syn blend diesel oil or euro oil at times. Owned both since new. Front and rear diffs and transfer case are also still good. Just oil.
This ^^^^
Our 2016 Suburban's 6.80E went at 81k. I did everything I thought to keep it going but it still went.
One must turn off AFM, as well as retune the transmission like stated above. Ours was rebuilt with upgraded parts and billet converter and now it drives great. Like a different transmission. We are hoping to get a long life out of it. Can't afford anything new these days. Just got back from a trip to the NC mountains and got 18.8mpg on E85. On a full tank of 93 we got 21mpg. This is with four adults and the back packed to the top and a wheel chair. Here E85 is a dollar cheaper than 87.
I replaced the 6L80e torque converter. I did it as preventative mx while doing an engine rear main job 3+ yrs and 44k miles ago when we purchase the vehicle. I called a respected tranny shop and asked what I should do while I had it out. They said the torque converter was the weak link. I also change all external seals I could get to.
They have AFM
What brand/model of converter do you recommend? I have a ‘14 Sierra with about 77k miles…planning to change out the TC proactively.
I installed a Presion brand, pt# p4646, cost about $225. I don't tow or hot rod my 07 Yukon w/6L80e.
I use B&I out of Oklahoma City & Performance Torque Converters of Texas out of Kennedale, TX. for stock stall.
Use Circle D out of Houston, TX for higher stall/competition converters.
I've heard good stuff about Circle D
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2007 and 2008 will be a 4L60.
The 4L60 is no Hercules but gets a bad rap from 9/10 owners of the GMT400 and GMT800 trucks running them HARD and doing little to no trans maintenance.
Had a friend with an 08 Tahoe where at about 330k one of the AFM lifters collapsed. Instead of rebuild, opted for a low mileage junkyard LY6 6.0 and a take out LS3 cam. Nice thing here is no-more AFM to worry about. Sweet truck with good healthy power.
The 4L60 is no Hercules but gets a bad rap from 9/10 owners of the GMT400 and GMT800 trucks running them HARD and doing little to no trans maintenance.
Had a friend with an 08 Tahoe where at about 330k one of the AFM lifters collapsed. Instead of rebuild, opted for a low mileage junkyard LY6 6.0 and a take out LS3 cam. Nice thing here is no-more AFM to worry about. Sweet truck with good healthy power.
Not in a Yukon Denali
07 & 08 Denali come w/6.2L without AFM/DOD and a 6L80e tranny
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Correct, but OP asked about a 5.3 which would eliminate a Denali.
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