Charlie207
Full Access Member
Tuning aside, arent the 6L90s physically larger than 6L80s? I read somewhere they are 2" longer.
Wouldn't surprise me that they engineered the 80 smaller to juuuust barely last long enough, in order to save a few bucks.
6l80 tcc slip tuning stock clutch
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Tuning aside, arent the 6L90s physically larger than 6L80s? I read somewhere they are 2" longer.
Wouldn't surprise me that they engineered the 80 smaller to juuuust barely last long enough, in order to save a few bucks.
Marky Dissod
Full Access Member
The physical size difference is minimal. What's far more important:
The 6L90 is built to withstand more torque and RpMs (some of that extra size is internally important, some of it is just case strength)
GM OE 6L90 2500 tuning, not just TCC behavior, sacrifices a wee lil bit of NVH that your wife might whinge about, for durability & longevity towing & hauling
You're correct, the 90s are about 4-5 inches longer and those that went into diesel-equipped vehicles had an extra clutch and steel in the packs as well as stronger planetary carrier sets and the TMBX converters they came with had flanged hubs whereas the 80s converters did not. It's a stronger transmission all around, especially the diesel versions but it also suffers from the same general pattern failures/issues as the rest of the 6L family, particularly the 6L80.
Marky Dissod
Full Access Member
Is it a a safe guess that most 6L90s also work harder than most 6L80s?
I'm GUESSING that if a 6L90 lived the gentler life of a 6L80, the 6L90 might tend to last longer than the 6L80?
PLEASE, let me know if I'm guessing wrong here ... ?
That's impossible to say unless you either take surveys of sufficient sample sizes to draw such conclusions or the data is already out there, plus you'd have to quantify what it means to 'work harder' to ground the results.
Bottom line: they are all prone to the same type of failures, most of which involve the torque converter so it wouldn't matter how strong one variant of that transmission family is relative to the others if the converter's poor design is driving the majority of the breakdowns.
Marky Dissod
Full Access Member
Most 6L80 vehicles are personal transit appliances Towing / Hauling less weight less often compared to 6L90 vehicles which tend to be workhorses ... ?
I had the 6L90 in my 2015, 3500hd work truck. I absolutely loved that transmission. The torque converter did fail at 50k though (both 2015 trucks failed at similar miles?? The 2017s didn't have issues) It was replaced and then gave another 115k of additional service without 1 issue before being traded out. It was a heavy truck - 12k all day, everyday, and then pulled an 8k trailer a couple days a week.
The trans calibration was right on the money in my book. I'd take one of those anyday. And, it was driven in Chitcagoland it's entire life. That's probably the best drivetrain in my book - 6.0L with 6L90
The trans calibration was right on the money in my book. I'd take one of those anyday. And, it was driven in Chitcagoland it's entire life. That's probably the best drivetrain in my book - 6.0L with 6L90
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They also used the 6L90's in the cadillac ctv-s supercharged 6.2L
They are supposed to hold a little more torque , hence 90 vs 80
I thought some parts were interchangeable on these and the size diff
was like 1 inch or so... I've never physically touched a 90E
I imagine the "tuning" programming parts is really similar with TCC slip
patterns/numbers
They are supposed to hold a little more torque , hence 90 vs 80
I thought some parts were interchangeable on these and the size diff
was like 1 inch or so... I've never physically touched a 90E
I imagine the "tuning" programming parts is really similar with TCC slip
patterns/numbers
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