Towing with a half ton Torque converter lockup.

[The motor guy]

So I have a dodge ram 2500 cummins with the 68rfe trans and automatic transmissions usually drive me nuts, but not this one. What I love about this transmission is the torque converter stays locked most of the time when accelerating and in fact you usually have to really give it some throttle to get it to downshift whereas other trucks i've driven they unlock the torgue converter if you give it more than about 10 percent throttle to accelerate, so all it does is shift back and forth very frequently and i'm not engineer, but that can't be good long term.

 

[spasm3]

Should run cooler locked up.

 

[Lubener]

I would turn off the lockup while towing.

 

[supton]

I would turn off the lockup while towing.

Do you think the TC clutch is weak?

 

[tnt_motorsports]

So I have a dodge ram 2500 cummins with the 68rfe trans and automatic transmissions usually drive me nuts, but not this one. What I love about this transmission is the torque converter stays locked most of the time when accelerating and in fact you usually have to really give it some throttle to get it to downshift whereas other trucks i've driven they unlock the torgue converter if you give it more than about 10 percent throttle to accelerate, so all it does is shift back and forth very frequently and i'm not engineer, but that can't be good long term.

It sounds like your tranny is working as intended with the lock up but the hunting is not good. Lock it out of 6th gear by selecting 5th gear if it is bouncing back and forth. You will want to maintain between 1,600 to 2,400 RPM to keep it in the proper torque range for towing and allow the TC to lock up.

I have a 2012 2500 with a Cummins and 68RFE. Mine stays locked almost all of the time and that is what you want, but don't let it hunt. Allowing it to lock the torque converter is good. This way there is WAY LESS heat generated and heat is one big enemy or automatic transmissions. I pull a travel trailer that weights about ~11K with my truck and no issues. I love this truck for towing!

Just my $0.02

 

[ammolab]

His truck is just fine....read carefully what he said! “OTHER trucks”

”whereas other trucks i've driven they unlock the torgue converter if you give it more than about 10 percent throttle to accelerate, so all it does is shift back and forth very frequently and i'm not engineer, but that can't be good long term.”

 

[tnt_motorsports]

I would turn off the lockup while towing.

^^^^ no not this. You want the TC to lock up when towing otherwise your are making too much heat and wasting fuel. These trucks are built to pull you just have to know how to drive them. They hunt because it wants to maintain at least 1,400+RPM while towing. I keep mine between 1,600 & 2,400 RPM and don't have a problem. If mine hunts I lock it out of 6th gear.

 

[nascarnation]

I would turn off the lockup while towing.

Not good. They typically use a "looser" converter match (more slip) in a lockup converter. Will make lots of heat. Use it how the powertrain calibration engineers intended.

 

[wpod]

Most people don't know the torque converter generated the heat in an auto trans. There is a reason the trans fluid cooler routes from the torque converter to the cooler.

 

[wpod]

It sounds like your tranny is working as intended with the lock up but the hunting is not good. Lock it out of 6th gear by selecting 5th gear if it is bouncing back and forth. You will want to maintain between 1,600 to 2,400 RPM to keep it in the proper torque range for towing and allow the TC to lock up.

I have a 2012 2500 with a Cummins and 68RFE. Mine stays locked almost all of the time and that is what you want, but don't let it hunt. Allowing it to lock the torque converter is good. This way there is WAY LESS heat generated and heat is one big enemy or automatic transmissions. I pull a travel trailer that weights about ~11K with my truck and no issues. I love this truck for towing!

Just my $0.02

You certainly have the set up for heavy towing.

 

[ka9mnx]

What does the owners manual say about towing? A diesel generates enough torque so it doesn't have to downshift or unlock the convertor to spin up the engine revs like a gas engines.

 

[The motor guy]

His truck is just fine....read carefully what he said! “OTHER trucks”

”whereas other trucks i've driven they unlock the torgue converter if you give it more than about 10 percent throttle to accelerate, so all it does is shift back and forth very frequently and i'm not engineer, but that can't be good long term.”

You're the only one that read my post.

 

[CKN]

In tow haul mode at 65mph my 2018 Silverado w/the 5.3 and 6 speeds stays right at 2,000 rpm on flat Interstate-towing my 5.500 pound travel trailer.
The 6th speed other than being a "slush box" doesn't seem to hunt for gears at all.

 

[The motor guy]

What does the owners manual say about towing? A diesel generates enough torque so it doesn't have to downshift or unlock the convertor to spin up the engine revs like a gas engines.

Actually some.of.the newer v8 gassers spin the same or lower rpm than my Cummins.

 

[Lubener]

Do you think the TC clutch is weak?

Nope, just wouldn't use it pulling a trailor.

 

[supton]

Nope, just wouldn't use it pulling a trailor.

Sounds like you think it's weak. I mean, 3/4T pickup, pulling a heavy trailer should be expected.

 

[clinebarger]

Nope, just wouldn't use it pulling a trailer.

The trans will quickly overheat without the TC being locked pulling @ GVWR, My Allison 1000 locks in 2nd gear & stays locked while in Tow/Haul mode.

 

[meep]

Let it lock up! If towing heavy an unlockd TC will generate a ton of heat. If you’re concerned about the load, don’t pull in an overdrive gear. That can be a strain and creates more heat as well.

m

 

[Tomioka]

The trans will quickly overheat without the TC being locked pulling @ GVWR, My Allison 1000 locks in 2nd gear & stays locked while in Tow/Haul mode.

The bigger sisters the 2000 and 3000 series in Class 6 and 7 vehicles will lock up in first and in less than 10 mph and will stay locked thru the rest of the gears. Trans temp does not go above 170F even when fully loaded and without the need for an external tranmission cooler.