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Thoughts on the 6L80E

rjfguitar

rjfguitar

3/4 ton status
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So what is CK5's general consensus on this trans? When I bought my wife's 07 Cadillac Escalade I immediately found I did not like the shifting patterns of this trans. It constantly is trying to upshift and keep the RPM's as low as possible, keeping the lid on the sweet 6.2LS under the hood that yearns to rev and make me smile. I was hoping since we had an early equipped 6L80E, that maybe newer GM's would have improved shift patterns, I found that to not be the case when I rented a '15 Tahoe that suffered from the same constant up shifting. For those of you that havent driven one, I'm talking about when you are doing 35mph in town and it wants to up shift to it's deep 6th gear, combined with tall 3.42's in the diffs. If you want quick pick up to jump up to say 45 or so, it's got to down shift 3 gears.

My 2nd issue with this trans is longevity and strength. We noticed with our Escalade some erratic issues the last year or so. Delayed engagement of reverse, flares in between 2nd and 3rd, and when 3rd gear completely broke loose and the 6.2 revved to the moon when I was passing a Prius, I knew this trans was done at 140K. Getting ready to head out to go pick up the Escalade, my builder said reverse and 3rd were totally cooked and the other clutch packs weren't far behind. $3K for a new trans. He said he doesn't think it's a very tough tranny due to the clutch sizes and sees a lot of them come in for full rebuilds at or around the 100K mark.

I miss the 4L65E. It let the LS engines rev, it's cheap to rebuild, and GM had them down to a "T" on reliability. I've seen multiple Tahoes/Yukons pass 300K on original trans.
 
I have heard a little of the same as far as strength and longevity. I don't like the way that they are programmed either.
I have a company truck with one. Same problems as you described. It hasn't died yet..... it has 138K on it...
 
skunked said:
have you looked into a software upgrade?
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Are you talking about the latest GM dealer software or something aftermarket? We have the latest software as it was reflashed in 2014 during the "cam actuator nightmare of 2014" as we started calling it.

This is the wife's ride, I'd prefer to leave it bone stock, software and all. I mean, don't get me wrong it's not a HUGE deal the way it shifts, when it annoys me enough to do something about, I just throw it into manual mode and shift it myself with the rocker switch.
 
I think the main reason it bothers you so much is you don't drive it enough. Yes it shifts a lot, but they want to maintain a constant rpm for MPG.
 
I'd say it bothers him because it's stoooopid. I get so annoyed with it I drive mine in tow/haul mode 90% of the time. Mine is a '15 GMC. Love the truck, hate the nanny's and bullshit factory tune. I'm going to start shopping for a tuner.

My most annoying scenario is left turns in biggish intersections. Midway through the turn it plows through shifts hitting fourth before you're at the point you want to accelerate as you're straitening out. Awesome, it's now spinning at 800 rpm and needs to drop two gears before it will get out of it's own way...so you step on it a bit more, it does finally downshift at 50% of WOT, down to second, and takes off way more than you wanted.

I'd be angry at GM (I kinda am) but a lot of this BS starts with the epa tests. I actually wish GM would have done what VW did. Tune for epa/emissions/hippies...but have a good driveable tune reload as the default later.
 
Had some complaints of this in our service dept. Pretty much the norm. 8speeds are going to be more busy and make bigger downshifts when power is needed.

Chalk it up to EPA and fuel savings. Steepest gear we can order is 3.42's and those are "towing" gears. Steeper first and second gears make up for it, but the strategy is to get into od quickly. How else are they going to get 20+ mpgs out of a 1/2 ton truck with a v8?

Around town I never even notice it I'm so used to it. Only time I do is if I'm on the highway, cruise on and start climbing. Then as it drops speed it will do a 2 or 3 gear downshift instantly taking rpms from 1500 to almost 4,000. It will spook someone not prepared for it. My habit has been to kick it out of cruise on grades. I can carry momentum into the hill and climb it without kicking down 3 gears.

We've done software updates for various issues, but none address this concern.

I've looked at it this way, more gears=more shifting. How many remember a three speed bike and then switched later to a 10- speed or later to a 18 or 21 speed bike. Didn't shift the 3-speed much, but depending on the terrain you can all use all of the gears on a mountain bike. All the trans is trying to do is get to od quickly without loosing power, but the controls know where the power is made and if the demand is made it knows what gear to get into. If that means it makes a 3 gear downshift, it's going too.

I drove a 8-speed Stingray vette last weekend and granted 460hp means it's got power anywhere, but it got into higher gears fast if I left in in drive. It's going in that direction. 10-speed trannies out out there.

I'm a little too young to recall this personally, but guys didn't like 3 speed autos compared to 2 speed powerglides when they came out either.
 
I hardly see, in reality out on the real road, that GM allowing the trans to upshift way too early and trying to keep the engine below 2K RPM's actually equals out to better fuel mileage when the engine is far below it's powerband and good vacuum. The real results show that, my 30yr old wife drives like she's 70 and still can only get 10.5mpg in town. Her old yukon with the 5.3/4l65E got 15 in town. Granted, it's a healthy 6.2 with AWD, but they scale out pretty close to the same weight. I'd hate to do the math when I'm driving.

As far as aftermarket programming, I've never looked into anything on what is available and what it can do, but I shouldn't have to fix what GM could have so easily. That, and I just don't want to mess with anything aftermarket.

All in all it's not a huge deal. It's just that the 4L60 always seemed to be in the "right" gear in nearly any driving condition or speed, where the 6L80E always seems to be in the wrong gear when you are under 65mph.

Not to shift the thread, but I'm really hoping this doesn't carry into other brands. I'm thinking to start shopping for a newer 2012+ Dodge Cummins with either the 68RFE or Aisin autos and hope they don't suffer from the same issue.
 
Their fuel economy numbers are BS anyways. It may be possible to achieve the highway numbers, but only if the cruise speed is no more than 60 mph. I feel the race to overdrive is a clutch pack killer

I'd say the 6 speeds behind the new diesels would be a whole different experience due to the amazing tq of the new diesels. For the gas trucks, this isn't just a GM thing.
 
tRustyK5 said:
Their fuel economy numbers are BS anyways. It may be possible to achieve the highway numbers, but only if the cruise speed is no more than 60 mph. I feel the race to overdrive is a clutch pack killer

I'd say the 6 speeds behind the new diesels would be a whole different experience due to the amazing tq of the new diesels. For the gas trucks, this isn't just a GM thing.
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Tell me about it. Reverse, 3rd, 4th, and 5th all were burnt up.
 
I haven't driven one but I've always figured the new 6 speeds would be shift happy.

As for the Dodge with the Cummins, I'd go with the Asian trans. The 68rfe is already know for only going 150k average even behind a stock engine.
 
Got a 6l80E on my G8. Nobody is really happy w/ the programming on it for shift points, but they can defiantly be improved through programming. The biggest weakpoint I've heard is the torque management on them. Turn it off and the tranny will last longer.
 
I think eliminating torque management on these will shorten the life of this trans.' it pulls fuel and timing just a moment before the shift to lessen the shock on the trans. So far we have seen the converter clutch as the leading cause of failure, the carbon fiber lining comes off , ruins the pump, clogs the filter and takes out the trans. The TCM for this unit is mounted INSIDE of the transmission so all debris in a ruined trans also contaminates this. There is more to rebuilding one of these than replacing clutches, most need a pump and cover and TCM rebuild. We use a different style of clutch friction in the converter that holds up much better and do a few other upgrades as well. My wife has a 2013 Tahoe with this trans and I prefer the 5.3 4L60E combo in my 2005 Suburban.
 
Thought the torque mgt was in concert w/ the softening of the shift points - to make the shifts more 'acceptible'?
 
These transmissions depend heavily on torque management for durability. GM made them smaller and lighter than the earlier transmissions but also changed how they shift as well. The older 4 speeds did the whole shift in a single motion. The new transmissions shift into neutral, change the gear then shift back into drive with each shift. Combine that with a soft application of power by pulling fuel and timing during shifts, the trans doesn't get shock loaded as hard.

Lots of guys are using the 6 speed transmissions in Ultra4 racing applications and they work very well. The difference there is that the guys are either running paddle shifters, or have significantly changed the TCM programming to remove the comfort portion of the shifting by jacking up the pressures and reducing shift times to reduce slippage. With big coolers, the transmissions offer great gear splits and a nice deep first gear for offroading applications.

You can get a far better feel and better shift timing by adjusting the programming in the TCM with an aftermarket tuner like EFILive.
 
I just hate that mine needs to be floored to go "O shit okay I need to double down shift"...

Although mines probably much better in a 3/4 ton with 4.10s than a burban with 3.42.


On a side note is there no 6L60e? they just stuffed an 80 into everything?
 
Stomis said:
I just hate that mine needs to be floored to go "O shit okay I need to double down shift"...

Although mines probably much better in a 3/4 ton with 4.10s than a burban with 3.42.


On a side note is there no 6L60e? they just stuffed an 80 into everything?
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Far as I know the 6l80 is in half-tons and cars. The 3/4 and 1 tons get the 6l90.
 
Greg Ducato said:
I think eliminating torque management on these will shorten the life of this trans.' it pulls fuel and timing just a moment before the shift to lessen the shock on the trans. So far we have seen the converter clutch as the leading cause of failure, the carbon fiber lining comes off , ruins the pump, clogs the filter and takes out the trans. The TCM for this unit is mounted INSIDE of the transmission so all debris in a ruined trans also contaminates this. There is more to rebuilding one of these than replacing clutches, most need a pump and cover and TCM rebuild. We use a different style of clutch friction in the converter that holds up much better and do a few other upgrades as well. My wife has a 2013 Tahoe with this trans and I prefer the 5.3 4L60E combo in my 2005 Suburban.
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That is what I just found out. My rebuilder just did the internals and at the last minute on a test drive had an issue with a code and a solenoid in that coil pack. Whole new coil pack coming. Up to about $3200 at least on this rebuild.
 
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