L31/6L80e

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RDF1

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That's gotta play hell on the tcc.
Thats why the crappy things barely make it 100,000 miles.
Plus the converter is stamped steel so the clutch and front cover aren't even parallel. So its uneven wear at a high rate.
I've replaced a bunch of those transmissions this year and its the exact same thing in every one. Tons of metal contamination from failed TCC.
 

Christian Steffen

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Thats why the crappy things barely make it 100,000 miles.
Plus the converter is stamped steel so the clutch and front cover aren't even parallel. So its uneven wear at a high rate.
I've replaced a bunch of those transmissions this year and its the exact same thing in every one. Tons of metal contamination from failed TCC.
Yeah I've heard of a lot of failures from them as well. Sucks because it's giving the 6l80e a bad rap.
 

Supercharged111

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The last gen 4L60 did the same thing and didn't suck any more than its predecessors, what makes the 6L worse? Or is it?
 

L31MaxExpress

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The last gen 4L60 did the same thing and didn't suck any more than its predecessors, what makes the 6L worse? Or is it?

The only 700r4 derived pile of junk I have ever had that lived was the one that should have failed 200K miles before it did. It was a 10/82 build with the small input shaft, weak pump, etc.
 

RDF1

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The last gen 4L60 did the same thing and didn't suck any more than its predecessors, what makes the 6L worse? Or is it?
Last gen 4l60 as in the 2009ish era? The ones ive messed with didnt slip the converter.
Some love the 6L cause it has more gears yada yada yada.
In all the cars and trucks ive tuned over the years id gladly take the 4l80 over the 6L and 8L tranmissions. I just cant get use to the clutch on clutch style shifting and on quite a few of the trucks the built 6L trans are very expensive where a stock 4L80 holds up better to the power. Tuning the 6L is tricky to get the shift timing correct without flare/binding and the torque signal from ECU is very sensitive on tuning. Wrong injector data, skewed MAF/VVE tables can cause havoc on the shift timing/pressure.
 

Christian Steffen

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Last gen 4l60 as in the 2009ish era? The ones ive messed with didnt slip the converter.
Some love the 6L cause it has more gears yada yada yada.
In all the cars and trucks ive tuned over the years id gladly take the 4l80 over the 6L and 8L tranmissions. I just cant get use to the clutch on clutch style shifting and on quite a few of the trucks the built 6L trans are very expensive where a stock 4L80 holds up better to the power. Tuning the 6L is tricky to get the shift timing correct without flare/binding and the torque signal from ECU is very sensitive on tuning. Wrong injector data, skewed MAF/VVE tables can cause havoc on the shift timing/pressure.
This is definitely true, they're finicky to tune. 4l80 is king
 

L31MaxExpress

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This is definitely true, they're finicky to tune. 4l80 is king

I have a 4L80E in the Tahoe, 4L85E in the Express and both G20s have 87-90 TH400s that GM named 3L80 that used TH350 output shafts. If I ever have to rebuild them it is likely they will get TH400 output shafts and output housings, but they are both holding up well. Aside from having to play with the governor to get the TH400 to shift where I want it, I like them as much or more than the 80/85E. Both have 3.08 gears so the cruising rpm is still fairly low even with a non lockup converter and no overdrive.
 

Christian Steffen

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I have a 4L80E in the Tahoe, 4L85E in the Express and both G20s have 87-90 TH400s that GM named 3L80 that used TH350 output shafts. If I ever have to rebuild them it is likely they will get TH400 output shafts and output housings, but they are both holding up well. Aside from having to play with the governor to get the TH400 to shift where I want it, I like them as much or more than the 80/85E. Both have 3.08 gears so the cruising rpm is still fairly low even with a non lockup converter and no overdrive.
Huh that's interesting! Th400 is definitely good too, I just like my OD and lockup. Lol
 

Supercharged111

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I knew they were tricky to tune and also that they're not on the same level strength-wise as a 4L80. But I also thought they were tougher than the 4L60 all this time. Doesn't the 4L80 just overrun every gear with a sprag? The clutch off then on has to happen at just the right time or you end up smoking the trans, the guy who makes the TCM OP used was telling me about that. I figure if there's a decent Camaro or Corvette tune to steal, that'd be the way to go. I'll have to crack open a stock tune for one and have another look at all the crap I was too scared to touch and see how much there really was. I'd tuned a CTSV a while back and wouldn't touch the shift timing stuff, but since it was speed density that messed up how much torque the ECM reported to the TCM so I bumped that constant by 10 or 15 percent and it made a big difference in how quick it shifted. It was plain wrong before I did that.
 

Erik the Awful

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both G20s have 87-90 TH400s that GM named 3L80 that used TH350 output shafts.
That explains a mystery. Roscoe originally had a 454, which means that it also had a TH400. When I pulled the driveshaft, it had the smaller TH350 front yoke and I was wondering if it was actually a 350 truck. Now I know, it didn't have a "TH400", it had a "3L80".
 
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