Can't order 4.10's!

[Powder Extreme]

So you guys are saying that cruising at 2080 Rpms, this engine will be happy? This would be fifth at 69 mph with 3. 73's or 1700 in sixth.

Absolutely! I've towed several thousand miles in Montana mountains grossing heavier than you will be with 3. 73's, the engine is very happy. I'd be willing to wager you will find yourself running in 6th gear quite a bit as well. Long, flat, wind free stretches it will purr along at 1,700rpm so well you will be surprised.

 

[BILLUA]

I am towing a 14K toy hauler in the mountains of Utah and Nevada. The 4. 10's do this effortlessly. So effortlessly that I may go with 3. 73's on the next truck... Or not

I am very happy with the 4. 10's. I am in 6th/lock on all but the steepest climbs on the hot days with high density altitudes. I cruise 70-75 on the interstates. Empty, I get close to 16 mpg. On My last trip to the mountains, I got right at 10mpg towing the trailer round trip.

The mission for my truck is 95% towing.

 

[Powder Extreme]

The 2012 with a 68rfe is a totally different animal than a '13 with an Aisin.

 

[BILLUA]

Interesting. Didn't realize a final trans output ratio of . 630, Aisin to . 625 68 RFE would make it a whole different animal.

I am willing to learn what makes it so. . My next truck will most likely have the Aisin

 

[mpaulson]

The Aisin runs basically 200 rpm slower in fifth and sixth gear compared to the 68Rfe.

 

[RustyJC]

How can that be when the 68RFE has a TALLER 6th gear ratio (0. 625:1) than the Aisin (0. 630:1)??

Rusty

 

[MCSloan]

The 68RFE with 3. 73 rear in 5th gear is nearly the same final ratio as the AS69RC with 4. 10 rear in 5th gear. 5th gear ratio in 68RFE is 0. 82. 5th gear ratio in AS69RC is 0. 77.

 

[RustyJC]

My statement was addressing SIXTH gear as stated in post #25. With the same final drive axle ratios and tire sizes, how can an engine turn 200 RPM slower at a given road speed with the Aisin (as was stated in post #25) than the 68RFE?

Rusty

 

[MCSloan]

It can't. For all practial purposes they both the same ratio in 6th gear.

 

[RustyJC]

Precisely my point.

Rusty

 

[Powder Extreme]

When I say a different animal, I mean the motor and how it is programmed. I didn't say it would be different rpm. 200lbft more torque and a different torque curve is what makes its a different animal than a 2012.

 

[RVTRKN]

But the stress on the lower ratio will wear faster, and if you have 3:42's, change the oil as required by Dodge. That is expensive to maintain the warranty, their oil is ridiculous in cost. Which brings me to a question, what oil should I use now that my warranty is up. I know it should to be synthetic, but what oil is the best for my 3:73?

 

[BILLUA]

So the 2013 has 1000 Ft/lb's of torque? That would make it a whole different animal than my 2012 with 800 Ft/lbs...

 

[mpaulson]

Take a look at the chart below and you will see the rpm differences for the two transmission's. The 68 Aisin has the same ratios as the 69 Aisin. Take note that this is with stock 17" tires.

 

[RustyJC]

If the 6th gears effectively have the same ratios (0. 625 versus 0. 630), the RPMs at a given speed will effectively be the same so long as axle ratios and tire sizes are constant and the torque converters are locked up. Mechanically, it can't be any other way. As far as gears 1-5 are concerned, if the ratios are different, the RPMs at given speeds will be different.



Rusty

 

[mpaulson]

yea, I was off on including 6th gear in my comment, but fifth is about 200 rpm slower with the aisin transmission.

 

[SnoKing]

Seems to me that RAM has removed a lot of torque limiting at lower RPM with these new engines with Aisin trannies! I think that power has always been there down low, however they limited the torque to protect the transmission! With the Aisin they turned in loose!!!! I drove a new 2013 SRW 3500 and thought that the 3. 42 where to tall, but they will not install 3. 73 in the SRW trucks. With a 7K Rear GAWR it would tow a fairly large 5th wheel, and the tall gearing would become a pain. It would be like having an old 4 speed auto again!!!!

Chris

 

[mpaulson]

I put in my order and got the 4. 10's. There were no restrictions on any of the options on Monday when I did the order. As well when the dual alternator, 440amp, option came up during the build, it had not cost beside it!!!! So I took it. The 220 amp option would have been $95?!?!?? May cost me 1/4 mpg or something, but whatever. That will help with the Pacbrake 4 cfm, 40 amp 100% duty cycle air compressor that I have ordered to install when I get the truck. The 4. 10's will have me at 1900 rpm at 69 mph/110kmhr. And if for whatever reason the load is too much or headwind etc, I will be able to do the same speed in fifth at 2280 rpm comfortably.

 

[mpaulson]

Seems to me that RAM has removed a lot of torque limiting at lower RPM with these new engines with Aisin trannies! I think that power has always been there down low, however they limited the torque to protect the transmission! With the Aisin they turned in loose!!!! I drove a new 2013 SRW 3500 and thought that the 3. 42 where to tall, but they will not install 3. 73 in the SRW trucks. With a 7K Rear GAWR it would tow a fairly large 5th wheel, and the tall gearing would become a pain. It would be like having an old 4 speed auto again!!!!

Chris

When I test drove both the 3500 dually 385 hp and a 2013 5500, they both had nasty lag when you first get on it for the first few seconds. I have read that this is because of the snap idle emissions test requirement crap and the turbo needs to develop enough boost before the fuel gets to giver. Kind of sucks, but it will help save tires and hard parts. My sisters 2012 has start out lag as well.

 

[mpaulson]

Thanks for the help guys. It gave me confidence in where the power band is on this new motor. Shouldn't have any issue with 1900 rpm loaded towing from what you all said.