3:73 or 4:10

[kcook]

I have to assume this discussion is about the 6. 7 and the 68RE transmission... Being that it's in the 4th gen forum. I have had both a 2002 5. 9 4. 10 gears, and now 2011 with 3. 73. I can say towing with my 2002 I would not have wanted anything else, although it never bothered me to do 2300-2500 rpms "don't understand what the issue is here???" Maybe the noise? Not towing well the 3. 55 would have been nice, but after watching my brother in law struggle with that set up towing, wouldn't have been worth it to me. I live in WA. though and every direction you go it's over a pass... Just to make it apples to apples my brother in law had a 2001, and I 2002 all the same except for gearing about 400HP, and both DTT 47RE transmissions. He finally swapped to 4. 10 front and back...

 

[kcook]

Now on to the topic - The new trucks are a whole new animal, the 3. 73 and the 4. 10 geared trucks with the 6speed automatic Trans run relatively low RPMS going say 70 mph 4. 10 I believe is under 1800 rpms. much rather gotten the 4. 10, cause physics will tell you the 4. 10 gears have a significant mechanical advantage over the 3. 73 this is undesputed, the max tow package will gain you a significantly higher tow rating so the engineers agree also, not to mention they have added some hardware to control heat in the rearend, power steering, and transmission. I just couldn't pass up the deal on the laramie longhorn truck I bought. Now in the real world as for mileage after numerous correspondance with other 4th gen owners I will better the guys with 4. 10 gears by maybe a mpg, and after asking the chrysler engineers the question "does lower rpms = better fuel mileage" their response was the truck drive train was designed to operate efficiently at certain rpms and lower did not equate to better fuel economy... That was during an open question session on cummins forum I believe you can go over there and reference the whole Q&A. I know from experience that low rpms means lower line pressure in the auto trans that equates to failures... You can read for days about that topic, maybe months...

So put me in the catagory plus one for the 4. 10 if you tow, especially if you tow heavy.

 

[NIsaacs]

With modern HPCR engines I don't believe higher gears means higher fuel economy. It doesn't matter what gears you have it takes "x" tq to go 70 mph. If you have 3. 73's your engine has to make 10% more tq to get that "x" tq to the wheels to maintain speed than a truck with 4. 10's. So in order to see better fuel economy from lower rpms the 10% difference in rpms has to be able to make more power with less fuel. This may have made a difference on older engines, but modern ones don't care nearly as much about rpms.

I think based on the OP's question of a new truck with the double overdrive 6 spd. auto, the 4. 10's are a good choice.



However all trucks with 4. 10 gears are not always best. Yes, the trq. the engine requires with 4. 10's is less in any given gear v/s 3. 73's. But..... with gear choices in the transmission you can mitigate most of the gains or duplicate them.



For instance with my '01, I would much rather pull x hill with x load in 5th with 3. 55's then I would with 4. 10's and 6th. And I dang sure would rather come home empty in 6th with 3. 55's v/s 4. 10's, I hate 4. 10's with one overdrive, running empty in the west, with 75 mph freeways and 100 miles from no-where:-laf



Nick

 

[HBarlow]

My old '01 with 3. 55 gears was not ideal either, just different challenges. It grunted and strained to start the load with a 14,500 lb. fifthwheel and required shifting down on grades. Returning home empty it was great though as you said.

I guess manual six speeds are marginal for heavy towing. They're either geared too low for good towing or too high for highway cruise. A seven speed would offer a big improvement.

 

[RustyJC]

I guess manual six speeds are marginal for heavy towing. They're either geared too low for good towing or too high for highway cruise. A seven speed would offer a big improvement.

Many times I wished for a TALL overdrive 7th gear on my 2002 dually with 6-speed and 4. 10s for Interstate driving when not towing. That would have been nice.



On the other hand, I have no complaints whatsoever with my 68RFE with 4. 10s either towing or running empty. The double overdrive gearing takes the pain out of living with 4. 10s when running with no load.





Rusty

 

[RMcKinney]

Phil-Don,

We all know the weak link in our set-up is the Transmission.

The 4:10 will give tour Transmission help in being trouble free EVERY time you pull.

RMcKinney 1995 2500 267000 still stock.

 

[NIsaacs]

My old '01 with 3. 55 gears was not ideal either, just different challenges. It grunted and strained to start the load with a 14,500 lb. fifthwheel and required shifting down on grades. Returning home empty it was great though as you said.



I guess manual six speeds are marginal for heavy towing. They're either geared too low for good towing or too high for highway cruise. A seven speed would offer a big improvement.

I agree with the 7spd! Although the 6spd auto is about as perfect as they come with todays choices.



When I built my Ford I used the 4. 10 due to off highway roads and loads. With the two trannys I have a 1st. gear ratio of 7. 59 and double overdrive of 0. 68, it worked good overall, however even 4. 10's were marginal with 34,000 lbs in soft ground or starting on a hill. It was dang hard to start a load with a tandem axle dually trailer sunk down 2 inches in soft ground. If I "missed" a gear on a 12 percent grade I would have to back back down and start over. I really needed the Aux. box with a 2-1 deep-under for off highway but really like the progressive 1. 27 under for normal use.



Nick

 

[HBarlow]

Many times I wished for a TALL overdrive 7th gear on my 2002 dually with 6-speed and 4. 10s for Interstate driving when not towing. That would have been nice.

On the other hand, I have no complaints whatsoever with my 68RFE with 4. 10s either towing or running empty. The double overdrive gearing takes the pain out of living with 4. 10s when running with no load.

Rusty

Likewise my Aisin.

The modern choices of six speed automatics combined with 4. 10 gears offering low load start ratio plus the reduction of a torque converter combined with two overdrive ratios is as near perfect a set up as is available in a light truck.

 

[CUMMINZ]

I was one of the first 6. 7L 68rfe trucks on the board and lived a hard life for quite a while trying to convince many with 3. 73 5. 9s to go to the 4. 10... It is a great combination. Now with my Yukon lock out hubs I will be using low 4x4 moving in and out of my favorite campsite in the BlueRidge mtns. :-laf

 

[Barbieri]

Amazing the responses I am getting from one question. In this case I know what I will be towing. And I pretty much know the terrain. If the gears don't make a difference why build a truck with options. Seems to me it makes a difference albeit a small one. So in the long run know what you tow and order accordingly. I think all around the 3. 73 is the ratio of choice. I am not looking to smoke the rear tires when I start off. Thanks for the info. Have a nice day.

 

[HBarlow]

Barbieri,

In the first place it is not "your question. " The thread was started by a member named, "Don. " It is his thread and his question.

Secondly, you posted your question in the middle of his thread which is considered impolite in internet communication. Your question should have been posted in your own thread. You were an intruder in his thread.

Thirdly, when you post a question in the future, state the answer you want or, if more than one answer is acceptable, list the acceptable answers so you will be sure to get only the answer you want.

 

[HBarlow]

Everytime someone asks for advice on the differential gearing he should order or which gearing is best several members try their best to defend their choice or lack of choice in simply buying a truck without knowing what gears it had or even knowing how it matters.

I wonder, has anyone ever actually specifically ordered a truck intended for towing with 3. 73 or 3. 42 gears?

 

[Barbieri]

It was my understanding that I started a new thread. All of a sudden I started getting your notes. So what happened. All the notices I received went to the thread I started except yours. It just showed up and I was puzzled about that. Enough said.

 

[AH64ID]

It was my understanding that I started a new thread. All of a sudden I started getting your notes. So what happened. All the notices I received went to the thread I started except yours. It just showed up and I was puzzled about that. Enough said.

Since you are subscribed to both you received info on both, and may have thought you were in the other thread.



Your post this morning looks like you thought you were in your thread.

 

[SnoKing]

For Bardieri, buying a 2500 to tow is also a mistake. A SRW 3500 has better capacity for hitch/pin weight for just a few hundred dollars more. You have a bumper pull now, however you may decide on a 5th wheel in the future and be limited by pin weight. SNOKING

 

[AH64ID]

For Bardieri, buying a 2500 to tow is also a mistake. A SRW 3500 has better capacity for hitch/pin weight for just a few hundred dollars more. You have a bumper pull now, however you may decide on a 5th wheel in the future and be limited by pin weight. SNOKING

Which is all pretty silly in itself as there is nothing that makes it any stronger. The suspension in the rear is a hair stiffer, but nothing to write home about (7%).

 

[SnoKing]

Which is all pretty silly in itself as there is nothing that makes it any stronger. The suspension in the rear is a hair stiffer, but nothing to write home about (7%).

Correct, the 3500 SRW now does not have overloads, and actually has fewer heavier leaps verses the 2500. I however will never by another 2500. I don't want to get busted by the weight police on RV.net!!



I run about 9500-9600 on a 8800 GVWR truck. Which by the way is licensed by the State of Washington at 12K. And for all the old 24V guys, I love my 4:10's towing and could not image doing it with 3. 55 with a auto. Except for the Dana 70, my truck like many other late 24V was built similar to a SRW 3500.



SNOKING

 

[AH64ID]

Correct, the 3500 SRW now does not have overloads, and actually has fewer heavier leaps verses the 2500. I however will never by another 2500. I don't want to get busted by the weight police on RV.net!!

I run about 9500-9600 on a 8800 GVWR truck. Which by the way is licensed by the State of Washington at 12K. And for all the old 24V guys, I love my 4:10's towing and could not image doing it with 3. 55 with a auto.

SNOKING

Ram made the rear spring change for 4th gens. On 3rd gen's all SRW's had the 4/1 main leaf pack, and 3500 SRW's had the 2 leaf overloads. The 2 leaf overloads are pretty useless on a SRW as it takes about 3K lbs in the bed to make them work and then your at a tire limit anyhow. DRW's had the 3/1 main pack and 2 leaf overloads.

On 4th gens the 2500 uses the same 4/1 leaf pack as the SRW 3rd gens, and all 3500's use the 3/1 leaf pack as the main pack and DRW trucks have the 2 leaf overloads.

The 3/1 leaf pack is rated at 7% more weight/in than the 4/1 pack. If you can feel that on a 8K lb truck you have calibrated kidneys!

Tires/Axles and State registration are the key numbers to look at, but that's another thread.

 

[SRichards]

O. K, I have a 2011 DRW 3500 w/3. 73's and auto trans. I tow a 14,000 fifth wheel and Have towed over 8,000 miles this year. It does fine in the flat country and some small hills. i have found that it pulls like a frieght train running 70 mph in 6th gear but I really dont care to run that fast. i would rather run 60-65 but find the truck seems to struggle more at those speeds. i usaully shift to 5th at 60 or below. The larger mountains out west are a whole nother story. I have posted this same topic on here and got varying opinions. So I have come to the conclusion that I either need to go to 4:10's or throw my warrenty out the window and do a full delete/programmer. IMO I think the 4:10's with this 6 speed auto would be the best setup for larger trailer weights,This is My Opinion though I have not pulled with this combo. Thanks Steve

 

[RustyJC]

IMO I think the 4:10's with this 6 speed auto would be the best setup for larger trailer weights,This is My Opinion though I have not pulled with this combo. Thanks Steve

We pull a 16K 5th wheel and, as stated earlier in this thread, think the 4. 10s are a great choice for our application, and the tall double overdrive 6th gear makes the 4. 10s easy to live with when we're not towing.



We routinely find ourselves running I-10 between Houston and San Antonio on our RVing trips. When the truck was new, it would get about 9. 5 MPG towing at 65 MPH with the cruise control on and drop to 5th on some of the rolling hills closer to San Antonio. Now that the truck has 6300 miles on it, on our last run back to Houston a couple of weekends ago, it got 10. 2 MPG on this stretch and never dropped out of 6th gear.





Rusty