Cummins automatic trannys

[ppine]

I had no trouble in 20 years towing with a 4R100 Ford trans behind a 7.3. I drove it 178 k miles before selling it. It had a trans cooler and trans temp gauge. I changed the fluid and watched the temp. Once in awhile towing a trailer I would pull over on steep grades like near Death Valley to let the drivetrain cool off, same with the brakes. the only thing I did not like about was only 4 speeds.

The 68RFE has 6 speeds which are easily controlled with the paddle shifters. The tow/haul is really good. I like it just fine and it much better than the Ford.

 

[ajparry89]

Did anything change between the cummins, either engine or tranny related, between the older 4th gens and say like 2014 and up? I know the gasoline ones got a different tranny after 13. any major differences I should know about with the Cummins? Thanks!

 

[06 Dodge]

Did anything change between the cummins, either engine or tranny related, between the older 4th gens and say like 2014 and up? I know the gasoline ones got a different tranny after 13. any major differences I should know about with the Cummins? Thanks!

Yes more TQ/HP and iirc improvements to the 6 speed transmission, the 2025 are said to be getting an update to engine and a 8 speed transmission

 

[ajparry89]

Yes more TQ/HP and iirc improvements to the 6 speed transmission, the 2025 are said to be getting an update to engine and a 8 speed transmission

When was that change? 2013?

 

[BigJohnJeep]

True statement. And the main reason the Aisin is "more reliable" is simply because you can't really tune them. If/when you can tune them they'll start puking too. This is true with any diesel truck with an engine/trans tune.

There is a built in shift flare in the 68RFE that some don't like and think that it's failing when in reality what it's doing is slowly rolling in the torque instead of dumping all of it at one time. They'll install a trans tune that ups the line pressure and removes the flare (fluid coupling) and hit the trans with 850+ lb/ft torque. Yes it shifts harder but is akin to smashing the gears with a sledge every time it does.

When you understand that it was designed to flare to protect the transmission, it's less concerning. I never pay attention to it.

I totally agree with this about shift flare. I came from a 2014 1500 with the 8 speed trans that was smooth as silk. I've had my 2015 2500 for a little over a year, and I'm still not used to the seat of the pants feel of the shifting. I just trust it's doing as it should. This truck only has 44,000 miles on it and I plan to use it a long time. I also have no plans of deleting or tuning. Just meticulous maintenance and using it as intended within the specs.

 

[mtnrider]

When was that change? 2013?

The 68rfe in the cummins has been basically unchanged since it was released. in 2011 they went to a different shift solenoid and I think in 19 they did makes some changes to the valve body other then that it's pretty much the same transmission at heart.

 

[Choupique]

the main reason the Aisin is "more reliable" is simply because you can't really tune them.

Yep. They also seem to completely cut fuel prior to shifts. Bad for winning drag races but excellent for transmission longevity. I wish the 68rfe did the same thing instead of the quick shifts with the flare. The 68rfe is a damn fast transmission, but it's a truck rated to gross 26k lbs. I dont need speed. I need to know it'll live as long as the engine.

 

[stevenP]

My 68RFE brought me to the dealer at only 12.5k miles. It was shifting both up and down extremely hard in 2nd gear. Truck was only 3 years old. Dealer said they were going to replace the trans, due to all the clutch material they found in the pan. My tuck is 100% stock in every way. Not deleted, no large wheel tire combos.

 

[ppine]

Leave it stock
Watch how you drive.
Do the maintenance.
Then your chances are good that you have no trouble no matter which trans you have.

 

[nlambert182]

You "can" delete it and the trans stay in tact, but that requires the ability NOT to turn up the power. All of my trucks were/are deleted, and none have had trans issues. All 3 68RFEs. I just came back from a 700 mile trip towing a 10k lb camper and it performed flawlessly. My 3500 routinely towed a 16.5k fifth wheel and never had the first hiccup.

It's two things:

1) Don't add power
2) Watch the right foot

Especially with a heavy load, but even when empty. If you drive it hard, you can expect issues... at least IME.

 

[HEMIMANN]

You "can" delete it and the trans stay in tact, but that requires the ability NOT to turn up the power. All of my trucks were/are deleted, and none have had trans issues. All 3 68RFEs. I just came back from a 700 mile trip towing a 10k lb camper and it performed flawlessly. My 3500 routinely towed a 16.5k fifth wheel and never had the first hiccup.

It's two things:

1) Don't add power
2) Watch the right foot

Especially with a heavy load, but even when empty. If you drive it hard, you can expect issues... at least IME.

How many miles are on those trucks? Failures are a combination of load, use, and heat.

 

[nlambert182]

Bear in mind, I was/am the second owner on all of these trucks and was able to meet/talk at length with the owners of the 16 and 18 to learn the history on them. Understand that not everyone has that luxury.

2012 had just over 165k when I sold it. From new to 50k it was an oilfield service truck out in Arizona. No idea what they towed but it had a gooseneck hitch in it and the inside of the bed was destroyed. It had good maintenance records, but from the looks of the bed it was well used. From 50k to 165k it spent about 40% of it's time towing a 11k lb fifth wheel. 60% was commuting.

2016 had around 145k when I sold it. Until 95k it was almost exclusively used to tow a 40' gooseneck with tractor equipment between Tennessee and Florida so almost all of the miles on it were towing. From 95k to 145k it spent about 40% of it's time towing a 16.5k fifth wheel. The other 60% was commuting.

2018 currently has 128k miles. Bought it with 106k. From new to 106k it was used on a farm in East Texas. It split time between hauling hay, tractors, and a competition BBQ trailer. From 106k to now it splits time between towing my 9800 lb travel trailer and commuting to work.

 

[Gr8bawana]

Bear in mind, I was/am the second owner on all of these trucks and was able to meet/talk at length with the owners of the 16 and 18 to learn the history on them. Understand that not everyone has that luxury.

2012 had just over 165k when I sold it. From new to 50k it was an oilfield service truck out in Arizona. No idea what they towed but it had a gooseneck hitch in it and the inside of the bed was destroyed. It had good maintenance records, but from the looks of the bed it was well used. From 50k to 165k it spent about 40% of it's time towing a 11k lb fifth wheel. 60% was commuting.

2016 had around 145k when I sold it. Until 95k it was almost exclusively used to tow a 40' gooseneck with tractor equipment between Tennessee and Florida so almost all of the miles on it were towing. From 95k to 145k it spent about 40% of it's time towing a 16.5k fifth wheel. The other 60% was commuting.

2018 currently has 128k miles. Bought it with 106k. From new to 106k it was used on a farm in East Texas. It split time between hauling hay, tractors, and a competition BBQ trailer. From 106k to now it splits time between towing my 9800 lb travel trailer and commuting to work.

Just goes to show these tannys are not as fragile as some people try to it sound. When used as intended they are very reliable and long lasting.

 

[nlambert182]

They absolutely aren't. I've seen these 68s pull some HEAVY weight and do just fine for hundreds of thousands of miles. I've seen the "bro" trucks come in with a burnt up trans at less than 100k miles because some teenager bought it, slapped on a 300HP tune and then go romp on it.

Just don't try to drag race it. The Aisin isn't without it's flaws too. Same with the GM designed "Allison" that so many tout as bulletproof. None of them are if you don't use them they way they were intended. Dad just had his Allison rebuilt about 2 months ago and he doesn't tow anything but a cargo trailer.

 

[ricky_bobby]