The two things about vehicles I understand the least Automatic transmissions and computer electrical things.
In the continued adventure to make my wife’s Suburban last us I spoke with a local transmission shop about installing an upgraded Billet torque converter for me.

He said while that is an option that they have had great luck tuning the torque converter to no longer lock up in gears 1-4 only 5 and 6.
He says they are seeing vast improvements in the longevity of the factory torque converters doing this and there is no real need to go to the effort to remove the transmission to install the new converter.

He said a tune would run me $300 and this would
Include tuning out the cylinder deactivation nightmare.
I already turn off the cylinder derivation with an OBDII plug in device.
It would be nice to free up my OBDII port.

So is this something I should consider over a new torque converter which will run me about $1500 installed?

Off topic, but my wife owns a 2017 Tahoe. Been looking at the devices that deactivate the AFM. What product did you end up going with?

Thanks,
CT

Why in the world would you want to change a torque converter?

We test our DEX VI ATF in that transmission for the equivalent of a gazillion miles, and we have done thousands of hours of tests on the friction controlling clutches in the torque converter. You wouldn't believe how much the TCC test rig costs. We've been factory fill ATF additive in GM transmissions for over two decades. It is filled for life quality, and tested for every conceivable failure mode. Gears, bearing, clutches, pumps, etc. are all evaluated under extreme stresses.

Can things go wrong? Of course. But, it would take a real transmission expert to differentiate that a torque converter clutch is bad, and why. Fluid degradation? Clutch glazing? Both? Maybe.

Regarding your tuning question...yes, a tune can help with AFM. AFM can be turned off in some GM trucks by a simple menu selection in the Driver Information Center. If not, it can be programmed out. This programming requires the VIN to be registered at the tuner's shop, in their reprogrammer device. Often this is about $125 just to register. Reprogramming to avoid TCC lockup in 1-4 but to maintain it in 5-6 sounds like a reasonable approach if you fear wearing out the clutches, and the cost seems minimal.

But, remember that allowing a TCC to slip, in gears 1-4, rather than lock up, as designed, actually increases both fluid temperature (degradation) and clutch wear. Not good. I don't know why the transmission shop favors this approach, but maybe they know something we don't.

Seeing what we put the transmission and fluid through, year after year, in our tests and field trials, please think very carefully about spending more money on the Suburban. R&R of a transmission for a torque converter requires new exhaust pipe donut gaskets, removal of cooler lines, draining of ATF, replacing the ATF, reprogramming the transmission control module, etc. If you are considering spending $1500 on a torque converter alone, I would much rather spend $4000 on a replacement GM transmission with a three-year unlimited mileage warranty. With this, you'll get everything new, and exceptional performance.

Agree with above in that unlocking the torque converter more often will create more heat and wear in the TC.

Tuning is no big deal so long as you are doing it for a purpose. My explorer ST has a tuned engine and trans. More power and much better shifting.

No reason not to disable AFM imo.

quote:

Originally posted by ChasinTails:
Off topic, but my wife owns a 2017 Tahoe. Been looking at the devices that deactivate the AFM. What product did you end up going with?

Thanks,
CT

I have been using the original Range Technology (since been bought by Holley) since we purchased the truck over 4 years ago.
Worth every penny!
https://www.rangetechnology.co...ts/afm-dfm_disabler/

quote:

Originally posted by 4MUL8R:
Why in the world would you want to change a torque converter?

But, remember that allowing a TCC to slip, in gears 1-4, rather than lock up, as designed, actually increases both fluid temperature (degradation) and clutch wear. Not good. I don't know why the transmission shop favors this approach, but maybe they know something we don't.

R&R of a transmission for a torque converter requires new exhaust pipe donut gaskets, removal of cooler lines, draining of ATF, replacing the ATF, reprogramming the transmission control module, etc. If you are considering spending $1500 on a torque converter alone, I would much rather spend $4000 on a replacement GM transmission with a three-year unlimited mileage warranty.

The reason to replace the Torque converter on the 6L80 is because it’s a poor design and essentially implodes sending all the bits into the transmission in turn destroying a perfectly fine transmission.
If you swap the torque converter to a proper one that won’t implode you don’t have to worry about replacing/rebuilding a transmission.
We have 109k miles and are lucky to have made it thing without loosing the converter/transmission.

I don’t have a good understanding of all the intricate details of how an automatic transmission actually works. I just know what it does so I don’t know why he would suggesting tuning it in the way he did over replacing the TC.

As for replacing/rebuilding the 6L80 everyone I have asked multiple places and everyone puts it in the $6500 range.

My C5 Vette was an auto (460LE). There were many parameters to "tweak" to increase performance and longevity. For example:

Shift time (in milliseconds)
Shift pressure
When upshifts happen (all gears, Speed and RPM)
When downshifts happen (all gears, Speed and RPM)

The only parameters available for the torque converter was the speed at which the converter clutch locks and unlocks. What gear it was in had nothing to do with it. Typically you want it to lock up when driving at a constant speed (freeway).This reduces heat in the converter and improve gas mileage. Mine was set to lock up at speeds > 45MPH and unlock at speeds < 44 MPH.
I hope that helps.

quote:

Originally posted by Lunasee:
My C5 Vette was an auto (460LE). There were many parameters to "tweak" to increase performance and longevity. For example:

Shift time (in milliseconds)
Shift pressure
When upshifts happen (all gears, Speed and RPM)
When downshifts happen (all gears, Speed and RPM)

The only parameters available for the torque converter was the speed at which the converter clutch locks and unlocks. What gear it was in had nothing to do with it. Typically you want it to lock up when driving at a constant speed (freeway).This reduces heat in the converter and improve gas mileage. Mine was set to lock up at speeds > 45MPH and unlock at speeds < 44 MPH.
I hope that helps.

The way I understand the lockup feature is it saves fuel economy by not dumping the wasted energy through the coolant system due to slippage when cruising at a constant speed, usually in the upper gears around 40 MPH or so.

A torque convertor is just a fluid coupler.
Unlocked they lose about 10% converted torque energy to slippage through the cooling system.
Locked will give 100% converted torque to the gears with no wasted energy at a constant speed.

quote:

Originally posted by powermad:

quote:

Originally posted by Lunasee:
My C5 Vette was an auto (460LE). There were many parameters to "tweak" to increase performance and longevity. For example:

Shift time (in milliseconds)
Shift pressure
When upshifts happen (all gears, Speed and RPM)
When downshifts happen (all gears, Speed and RPM)

The only parameters available for the torque converter was the speed at which the converter clutch locks and unlocks. What gear it was in had nothing to do with it. Typically you want it to lock up when driving at a constant speed (freeway).This reduces heat in the converter and improve gas mileage. Mine was set to lock up at speeds > 45MPH and unlock at speeds < 44 MPH.
I hope that helps.

The way I understand the lockup feature is it saves fuel economy by not dumping the wasted energy through the coolant system due to slippage when cruising at a constant speed, usually in the upper gears around 40 MPH or so.

A torque convertor is just a fluid coupler.
Unlocked they lose about 10% converted torque energy to slippage through the cooling system.
Locked will give 100% converted torque to the gears with no wasted energy at a constant speed.

This is true.

Long story short because I don’t remember a lot of the details.

Dealership I last worked at modified a new 2012 GMC with a 6L80, pulled the 5.3L and installed a LSX 454 together with other mods to brakes, suspension, etc. They kept the stock trans and reprogrammed it. It was sold in 2014 and trans tuning was “tweaked” several times, never really got it right.

I don’t remember the whole backstory as I wasn’t in on that part of it but when driving you had to watch the trans temp gauge for overheating together with 4-5 and 5-6 shift points and converter lockup in 6th gear.

I would have rather seen a 4L80 used it it.

Of course things have changed a lot since 2012 and I haven’t kept up with them.

Have you installed a thermostat bypass kit on that 6l80? It reduces the temp 15 to 25 degrees. Just another way to get more life out of the transmission.

Yes, trans temps are a major issue I frequently see 190* and don’t tow.
Mostly around town driving and back country roads.

I have a new thermal bypass that I installed different guts in to have the coolant kick to the trans cooler at 158* instead of 188*.

Hope to get it installed this weekend.

quote:

Originally posted by Black92LX:
The reason to replace the Torque converter on the 6L80 is because it’s a poor design and essentially implodes sending all the bits into the transmission in turn destroying a perfectly fine transmission.
If you swap the torque converter to a proper one that won’t implode you don’t have to worry about replacing/rebuilding a transmission.
We have 109k miles and are lucky to have made it thing without loosing the converter/transmission.

I don’t have a good understanding of all the intricate details of how an automatic transmission actually works. I just know what it does so I don’t know why he would suggesting tuning it in the way he did over replacing the TC.

As for replacing/rebuilding the 6L80 everyone I have asked multiple places and everyone puts it in the $6500 range.

Just a question, if the goal is to eliminate the potential failure of the TC, then how would changing the shift lockup points achieve this goal, since you'd have the same 109K TC in the transmission.

If the goal is to eliminate/reduce the chance of TC imploding and sending bits of metal through the trans, killing it, then the only solution would be a new TC, either factory or aftermarket, would it not?