3.42 or 4.10?

3:42 I pull a pontoon boat. I have crossed the rockies many times,( no boat). I have never really loaded the 6.7. That thing would pull anything reasonable with the 3:73. I would be happy with a 3:23 if I had the choice.

With a gas engine I would definitely go with the 4.10 gears but with the diesel the 3.42 should be fine. Even with a gas engine and the 3.42 the tow rating is around 10,000 lbs. and your camper and boat trailer are in the ballpark.

With a diesel engine the GCWR is over 30,000 lbs. and subtracting the weight of the truck leaves 22,000 lbs. for the camper, boat and trailer, passengers, and gear. Figure 15,000 lbs. for the boat, trailer, passengers, camper, and gear, and you are not even close to the capacity of the truck.

The 4.10 would make sense if you planned to tow a 20,000 lb. horse trailer otherwise it provides no real benefit according to the manufacturers towing specs for what you have specified as the total load weights.

The concern is the load on the rear wheels with the passenger, camper, and tongue weight combination. The tow load is incidental.

jerryleejr wrote:

Butch50 wrote:

jerryleejr wrote:
I know it depends on model year but in the past 3.73 was available with the 6spd manual, and 4.10w/auto now I was also told by my local fleet dealer that DEF would not be required until 2014 on the 3500 just the CC have used it since 2011. My two cents is get the 3.73 in manual. I want to see how the Aisin does for a model year or two.

JJ

According to Allpar your fleet dealer doesn't know what he/she is talking about. Also why would you wait to see how the Aisin trans works out, it has already been proven in the Cab Chassis for a few years already

Because the CC didn't run the HO motor, I believe this is the first model year the Aisin has been mated to the HO.

JJ

OK that kind of makes sense but the CC had more strain put on it than a pickup every well with the ratings the CC have. If the Aisin can handle those type of loads I would think that the it can handle the HO also but time well tell for sure if enough people spring the additional $2000+ for the trans and not just stick with the stock one.

Butch50 wrote:

jerryleejr wrote:
I know it depends on model year but in the past 3.73 was available with the 6spd manual, and 4.10w/auto now I was also told by my local fleet dealer that DEF would not be required until 2014 on the 3500 just the CC have used it since 2011. My two cents is get the 3.73 in manual. I want to see how the Aisin does for a model year or two.

JJ

According to Allpar your fleet dealer doesn't know what he/she is talking about. Also why would you wait to see how the Aisin trans works out, it has already been proven in the Cab Chassis for a few years already

Because the CC didn't run the HO motor, I believe this is the first model year the Aisin has been mated to the HO.

JJ

Egarant
Where are you buying your truck?
I spoke to Dave Smith Motors last week and the 3:73 and Aisin were the most common for the DRW. They didn't have many 4:10
I checked on an SLT 4x4 with a list price of almost $58k and with a $2700 dealer discount through the end of May the total price was around $47k.
May want to check them out. No hassle and invoice price minus rebates.

jerryleejr wrote:
I know it depends on model year but in the past 3.73 was available with the 6spd manual, and 4.10w/auto now I was also told by my local fleet dealer that DEF would not be required until 2014 on the 3500 just the CC have used it since 2011. My two cents is get the 3.73 in manual. I want to see how the Aisin does for a model year or two.

JJ

According to Allpar your fleet dealer doesn't know what he/she is talking about. Also why would you wait to see how the Aisin trans works out, it has already been proven in the Cab Chassis for a few years already

5th and 6th gear are both OverDrive gears. I tow heavy in 5th gear with my 3.73 gear and taller tires which essentially makes my gear 3.42.

I know it depends on model year but in the past 3.73 was available with the 6spd manual, and 4.10w/auto now I was also told by my local fleet dealer that DEF would not be required until 2014 on the 3500 just the CC have used it since 2011. My two cents is get the 3.73 in manual. I want to see how the Aisin does for a model year or two.

JJ

Strictly looking at the torque curve for the new hi torque motor you might be right. However also looking at the newer motors torque curve is very misleading as it peaks around 1600 RPM and drops like a rock the higher you go. Unlike the older 6.7L's flat torque curve.
There is also some misinformation it appears about the two transmissions ratios. Comparing the two they are almost identical with first second and third slightly different. At the end of the day transmission choice will make no difference.

My calculations show that with a 3:42 gear at 75 mph and high gear with an Aisin transmission I would turn about 1772 rpm. It was stated this is the sweat spot of the Cummins. Now for heavy towing at 65 mph and 5 th gear I get 1877 rpm. 6th gear would be 1535. I am sure a cummins will do just fine even with a towing load at 1535 rpm on level road where 95% of most towing is done.
Now for towing heavy in hilly country it may require using the gears in the Aisin. But that is what I thought a transmission was for. That is what the big rigs do when they come to a hill with large heavy loads.
If you look at the torque/hp curves of the 6.7 high output cummins you will see it was designed to operate at lower rpm's than the previous versions of the cummins. The 850 foot lbs of torque that is advertized so much is at 1600 rpm. That should be the sweat spot for the new high output cummins.