Cruise control and towing heavy - no no

[Cummins2014]

TryView attachment 107496 this 29K combo and report back starting on lets say a 3-4% grade.

Like I said, not having the Aisin, the 68 gets "MY" load moving okay, so no I don't see a disadvantage. You missed my point.

No there will never be 29K combined, so need to worry.

 

[kthaxton]

Remember it is final gear ratio that counts. 5th gear with 3.42 is about the same final gear ration that the 4.10's have in 6th. When you go from .77 ratio to .63 you really take away the torque multiplication advantage of the 4.10. Low rear diff gear help in the lower gears, however the lower Aisin 1st and 2nd over come the disadvantage of the 3.42's.

0.77 x 3.42 = 2.6334
0.63 x 4.1 = 2.583

Except every gear will be more useful, and you'll have six usable gears.

First gear with 4.10's will be more usable than 1st with 3.42's, and 2nd with 4.10 etc.....however, most importantly, 4th, 5th, and 6th will each be more effective at moving the load....and again, ALL 6 speeds are more usable.

And as a bonus, with 4.10's, all driveline components from the pinion gear forward have an easier life. You don't get that by using 5th gear with a higher ratio in the rear.

 

[SnoKing]

TryView attachment 107496 this 29K combo and report back starting on lets say a 3-4% grade.

That is OK, I a lot of these guys can not understand the concept of final gear ratio either.

Here are some first gear comparisons.
3.23 x 3.42 = 11.0466 (68RFE in 1st gear final gear ratio with 3.42's)
3.75 x 3.42 = 12.825 (Aisin in 1st gear final gear ratio with 3.42's)
3.23 x 4.1 = 13.243 (68RFE in 1st gear final gear ratio with 4.10's)
3.75 x 4.1 = 15.375 (Aisin in 1st gear final gear ratio with 4.10's)

 

[SnoKing]

Except every gear will be more useful, and you'll have six usable gears.

First gear with 4.10's will be more usable than 1st with 3.42's, and 2nd with 4.10 etc.....however, most importantly, 4th, 5th, and 6th will each be more effective at moving the load....and again, ALL 6 speeds are more usable.

And as a bonus, with 4.10's, all driveline components from the pinion gear forward have an easier life. You don't get that by using 5th gear with a higher ratio in the rear.

All that ends at the .63 OD ratio in the transmission with 4.10's. Engine power needed to more the load is identical between the two, 4.10's in Sixth and 3.42's in 5th. Where do you want to place the strain? On a weak .63 OD gear set or the diff. OD gears have always been the weakest link of trannies and are put there for low RPM cruising, not hard pulling. AAM axles are not noted to be weak in any ratio configuration.

 

[kthaxton]

I have never heard that the overdrive gears on the Aisin or the 68rfe are known to be weak spots as they were in the previous torqueflite based transmissions.
Have you heard this?

 

[SnoKing]

I have never heard that the overdrive gears on the Aisin or the 68rfe are known to be weak spots as they were in the previous torqueflite based transmissions.
Have you heard this?

Have you heard of 3.42 diffs failing?

 

[kthaxton]

Have you heard of 3.42 diffs failing?

You answer my question with a question?

Remember, you're trying to make an argument why using only 5 speeds of a six-speed is better than using all six. You gave the weak overdrive as an reason for that, I have not heard of this being a problem. The strength of 3.42's was never brought into question.

 

[SnoKing]

You answer my question with a question?

Remember, you're trying to make an argument why using only 5 speeds of a six-speed is better than using all six. You gave the weak overdrive as an reason for that, I have not heard of this being a problem. The strength of 3.42's was never brought into question.

Ron, will tell you that 1st gear with the Aisin 4.10 is hardly needed, and there is no way skip using it. 6th gear in 3.42 is very usable when not towing or towing at high speeds, which most that tow heavy do not do. Choose your poison. What percent of the time to you tow. Would you rather have 4.10's, be gear bound cruise while not towing? I had to for 14 years with our 2001.5 with 4.10 gears.

 

[kthaxton]

If I towed something that required a DRW, I most certainly would prefer 4.10's. At this point (owning a DRW) obviously towing has become the priority.
The big hips would be more bothersome than less-than ideal unloaded cruise rpm.

 

[gsbrockman]

I have never heard that the overdrive gears on the Aisin or the 68rfe are known to be weak spots as they were in the previous torqueflite based transmissions.
Have you heard this?

I wish someone would have told me this before I accrued 362k miles on my 2014.

It is indeed a miracle it made it that far....

I guess I’ll tow in 3rd exclusively with the 2018.

 

[Cummins12V98]

Until you have towed HEAVY as I have with both gear sets you are only guessing what you would do.

I have towed a way overloaded 14k dump trailer with my Sons 15 3500 SRW with AISIN grossing over 26k. Took off on a steep grade with ease!!!

 

[SnoKing]

I wish someone would have told me this before I accrued 362k miles on my 2014.

It is indeed a miracle it made it that far....

I guess I’ll tow in 3rd exclusively with the 2018.

Why did you go with 4.10's and not 3.73 like the 2014?

 

[gsbrockman]

Why did you go with 4.10's and not 3.73 like the 2014?

Because 3.73’s are NOT available on the 4500’s.

 

[SnoKing]

Because 3.73’s are NOT available on the 4500’s.

So you went with the tallest gears available on a 4500? Thought you liked compromise ratios?

 

[Cummins2014]

That is OK, I a lot of these guys can not understand the concept of final gear ratio either.

Here are some first gear comparisons.
3.23 x 3.42 = 11.0466 (68RFE in 1st gear final gear ratio with 3.42's)
3.75 x 3.42 = 12.825 (Aisin in 1st gear final gear ratio with 3.42's)
3.23 x 4.1 = 13.243 (68RFE in 1st gear final gear ratio with 4.10's)
3.75 x 4.1 = 15.375 (Aisin in 1st gear final gear ratio with 4.10's)

No, you two don't seem to understand. I understand perfectly, and if I was going to tow the 29K to whatever he is towing now, well then I would get the best truck for the task, but I am not, and I don't NEED the Aisin or anything lower then 3:42 gears.

 

[Wiredawg]

Wow, I have the Aisin and 4.88s on my new 5500. First trip out and loving it. In San Francisco today. There were some pretty steep grades I really appreciated starting out. I've had 3.54s, 3.73s, 4.10s, 4.44s and now 4.88s. I got by great with each of the these setups and the heavy trailers at the times. Frankly, I was skeptical about towing with CC on as this is the first truck to do it. I believe a lot of the ability to tow big grades with big loads is largely due to the special programming with the Max Tow Pkg in the Aisin. I have to say though that I still prefer kicking it out of CC on steep down hills: With the full exhaust brake engaged, I gain about 5 mph on the down hill and about 10 mph on the smart brake. Long 7% grades I topped doing 45 mph and I like going down them about the same speed. I like my transmission, my 4.88s, and the Max Tow Pkg.

I see and understand the expanded discussion about final ratios and good low end take off capability. I'm real happy with my low end pulling out of these steep grades, like some of the RV parks we've stayed at. I'm OK with doing 70 MPH doing approx. 2350 RPM... 75 is right at 2500. It's all good friends.

Well, Happy Trails and be safe. Ron

 

[gsbrockman]

So you went with the tallest gears available on a 4500? Thought you liked compromise ratios?

Wowwwww.....you’re certainly showing your lack of knowledge (or are your blinders still on maybe?)
Compromise this........
4.44’s are optional on the 4500’s

When you can reply back without being a TOTAL smartasssssss.......maybe I’ll reply back.

Nahhhhhhh....I guess I’ll just implement the IGNORE feature.

 

[Cummins12V98]

GS, what is your towing mileage with new truck compared to old truck same conditions?

 

[SnoKing]

Wowwwww.....you’re certainly showing your lack of knowledge (or are your blinders still on maybe?)
Compromise this........
4.44’s are optional on the 4500’s

When you can reply back without being a TOTAL smartasssssss.......maybe I’ll reply back.

Nahhhhhhh....I guess I’ll just implement the IGNORE feature.

You are the one that never answered questions regarding your 3.73, speed towing and the gear you used. So you set the stage yourself.

 

[gsbrockman]

GS, what is your towing mileage with new truck compared to old truck same conditions?

It seems to be down some. The 4500 weighs in minimally 1,500 lbs more. The engine is still “tight” IMO. The CM SK flatbed is not as aerodynamic as an actual dually bed. I’m riding on 19.5” tires and wheels that require more energy to get rolling. The ground clearance is more, possibly contributing to more turbulence underneath the truck and thus decreasing fuel economy.

On a side note...I recently delivered a HOT load to Loris, SC recently. I did get, hand calculated, 17.153 mpg bob tailing back home. I was happy.

I am more pleased with the overall towing experience with the 4500 vs. my previous 3500 (suspension, brakes, squat, etc)