Thinking of a new truck. Automatic trans questions

[EricBu12]

Yeah it does have 3:73. But it is a lot better than the 3:54 in my old 2001 2500

 

[mpaulson]

With the 3. 73, you just drop one more gear and you get the same effect while braking. All 4. 10 gears do is give you better launch power and shortens up the shift drops, otherwise with 6 gears, it's easy to achieve the same RPM's as the 4. 10 by running one gear lower. I routinely haul in the range of 30,000 gcvw and when I do, I set the chip to stock to avoid over doing it on the drive train.

 

[Gonzo 1066]

With the 3. 73, you just drop one more gear and you get the same effect while braking. All 4. 10 gears do is give you better launch power and shortens up the shift drops, otherwise with 6 gears, it's easy to achieve the same RPM's as the 4. 10 by running one gear lower. I routinely haul in the range of 30,000 gcvw and when I do, I set the chip to stock to avoid over doing it on the drive train.

This has been my theory for lots of years. Shifting down into a lower gear is easy. Why not pull in a stronger gear=5th gear in a 5600 6 speed. Overdrive has never been a strong gear in anyones transmission. What is not so easy is trying to get better fuel economy with a 4:10 gear.

 

[HBarlow]

With the new six speed automatics second overdrive is too tall for towing in a truck with 3. 73 gears and you give up trhe starting assistance provided by 4. 10 gears. 4. 10 gears provides a near ideal combination for towing at 14,000# or better with a six speed automatic.

With my 14,000 # fifth wheel sixth gear/second overdrive is perfect of towing at 65mph but is too tall for towing at 62 or 55. Fifth gear/first overdrive works fine for towing at 55 mph where the speed limit requires it.

Why buy a truck to be used for towing a heavy trailer with 3. 73 gears and be foreced to shift down one gear?

 

[Barry]

All six of my Rams have been bolt action 6 speeds. But now since the SS checks are hitting my mailbox, I think it's time for an Automatic. I am excited about the new Aisin trannie.



This thread has answered most all of my questions. Like Mr. Barlow, I have always believed the auto should have 4:10 gears because of the tall final drive ratio of the automatic(. 69 vs . 73 for the 5600 and . 79 for the G56)



What I do not know is what are the ratios of the Aisin trannie??

 

[NIsaacs]

Back in the day of 3 and 4 speed trannys, I can see not wanting to be forced into a down shift. That is a 25 to 30 percent drop. However a six speed anything, dropping one gear is cool.



Nick

 

[HBarlow]

Aisin ratios are:

1st 3. 74:1
2nd 2. 00:1
3rd 1. 34:1
4th 1. 00:1
5th . 77:1
6th . 63:1
Rev 3. 54:1

Top gear (2nd OD) has a final drive ratio of 2. 58 with 4. 10 gears. 5th gear (1st OD) has a final drive ratio of 2. 87. 4th direct has, of course, a final drive ratio of 4. 1.

When you consider these ratios it is a mistake to buy one off a dealer's lot with standard 3. 73 gears.

 

[Barry]

Thanx Uncle Harvey!



That answers the rest of my questions. Guess my next truck will only have 2 pedals... ... ... ... ... . one for go and one for stop!

 

[EricBu12]

Whats the Ratio of the 68RFE with 3;73?

 

[Barry]

Just multiply the final gear ratio in the trans times the gear ratio of the rear end to get the total final drive ratio... ... ... ... ... . it's gonna be tall!!

 

[HBarlow]

Thanx Uncle Harvey!

That answers the rest of my questions. Guess my next truck will only have 2 pedals... ... ... ... ... . one for go and one for stop!

You're welcome.

You'll love the six speed automatic integrated with tow haul mode and exhaust brake function. The new six speeds are very improved over the old 48RE.

 

[Barry]

In the 6 speed automatic, in which gear does the torque converter start to lock up?

 

[Bill Stockard]

In the 6 speed automatic, in which gear does the torque converter start to lock up?

Barry,



It's my understanding that the torque converter locks from 2nd gear through 6th gear. However, I can't tell it's locked when it's shifting up through the gears since it's so quick and smooth. When down shifting with the exhaust brake on, it's definately locked.



I drove a 2010 with the 68RFE at my local dealer this past week and what a difference from the 48RE! If anything could make me trade trucks, and it just might, it's operation of the 6-speed automatic in combination with the exhaust brake along the ability to shift the transmisson up and down manually. What a great combination!



Bill

 

[Barry]

Oooooooooooooooooo