Cruise control and towing heavy - no no

[Cummins12V98]

SnoKing looks like there is another one that needs to be edgumicated on gear ratios!

Remember when I bought my 11 HO Dually and started towing 28-29K combined with 3.42's??? OH MY GOD the sky was falling on this forum! BUT I proved the 3.42's DO have their place towing up to that range. RAM even thinks so just look at the towing chart. ONLY issue was taking off on grade I had to ease into it then hammer down after it got rolling. Now that the AISIN is available with the low starting gears the 3.42's are a WINNER!

Just to prove how well I feel they do I am considering that gears on mu new 19 or 20 and will be towing 33-35K combined at the same RPM just will be in 5th. THEN I will get mUCH better solo mileage.

 

[6V92TA]

Snoking, I suppose if you bought the truck for other duties besides towing, it makes sense.
only reason I have my 3500 DRW is to tow the Fifth wheel. other than that I drive a car because it makes alot more sense to drive a car than to drive a 1 ton pickup for commuting duties.

 

[6V92TA]

!2v, I don't need education on gear ratio's... but my main point is why would you order a truck for heavy pulling and then cripple it by giving it one or two unusable gears for pulling.. ?

 

[kthaxton]

!2v, I don't need education on gear ratio's... but my main point is why would you order a truck for heavy pulling and then cripple it by giving it one or two unusable gears for pulling.. ?

Agreed.

I suspect after towing with the 4.10's then going back to 3.42's with the same weight.....you'll have an "ah ha!" moment followed by a "Damn!" moment.

 

[Cummins2014]

Agreed.

I suspect after towing with the 4.10's then going back to 3.42's with the same weight.....you'll have an "ah ha!" moment followed by a "Damn!" moment.

I know we are going to hear from the OP ,and another for sure ,but I would hate to be towing anything more then what I am at 13,500 with the 3:42's that I have.

 

[SnoKing]

!2v, I don't need education on gear ratio's... but my main point is why would you order a truck for heavy pulling and then cripple it by giving it one or two unusable gears for pulling.. ?

Because it unhooks from the trailer! I only do not use 6th gear will towing. Ron, can tell you that a 4:10 geared truck hardly uses 1st gear and that he does not have a bobtail cruising gear like I do. Differential ratios is only half the story, final gear ratio which includes the transmission gear ratios completes the picture. At 60 MPH the 4.10 truck has a similar final ration in 6th gear as the 3.42 truck has in 5th gear. There is another thread where is posted the final gear ratios. The gains he has with 4.10 is offset by the .63 OD ratio of 6th gear.

 

[SnoKing]

I know we are going to hear from the OP ,and another for sure ,but I would hate to be towing anything more then what I am at 13,500 with the 3:42's that I have.

Do you have a 68RFE or Aisin transmission?

 

[Cummins2014]

Do you have a 68RFE or Aisin transmission?

68RFE, and are they that much different in fifth or sixth then the Aisin . I know the first two gears gets the load moving better then the 68, but after that, what is there.

 

[SnoKing]

68RFE, and are they that much different in fifth or sixth then the Aisin . I know the first two gears gets the load moving better then the 68, but after that, what is there.

The uppers gear ratios are similar. The 68RFE has a lower reverse gear. The Aisin trucks have the higher output HO engine.

Cummins with 68RFE 370/800
Cummins with Aisin 385/930

 

[Cummins2014]

The uppers gear ratios are similar. The 68RFE has a lower reverse gear. The Aisin trucks have the higher output HO engine.

Cummins with 68RFE 370/800
Cummins with Aisin 385/930

Then I guess with the higher output HO engine the 3:42 gears are okay, with your weight. I still would not like anymore weight towing with MY truck.

 

[Cummins12V98]

Agreed.

I suspect after towing with the 4.10's then going back to 3.42's with the same weight.....you'll have an "ah ha!" moment followed by a "Damn!" moment.

I have done the 3.42's with 29K combined they worked GREAT!!! You guys towing that much?

 

[Cummins12V98]

!2v, I don't need education on gear ratio's... but my main point is why would you order a truck for heavy pulling and then cripple it by giving it one or two unusable gears for pulling.. ?

We all got along with 4 gears that were POORLY spaced and if you have 5 that are well spaced that is not an issue to me at all as I have been there and dun that!

What is your combined weight?

 

[Cummins12V98]

I know we are going to hear from the OP ,and another for sure ,but I would hate to be towing anything more then what I am at 13,500 with the 3:42's that I have.

You have an AISIN? I towed 18K with my WRONG 3.42's and they were just fine, AISIN I would still be towing with it at 33-35K.

 

[Cummins2014]

You have an AISIN? I towed 18K with my WRONG 3.42's and they were just fine, AISIN I would still be towing with it at 33-35K.

I have never towed over 13,500 ,so my statement may change if I do. But for now with the 68RFE, and the 13,500 I just wouldn't want to tow much heavier, big thing is getting it moving. Once its moving a bit ,then I can get into it okay.

With the Aisin and lower 1 & 2 I would probably be a bit happier, but getting into that throttle with that 13,500 and that 68RFE, its too much driveline shudder or whatever it is, its actually no different then getting into the throttle with my old 7.3 , it was slower moving ,but the same shudder.

 

[SnoKing]

I have never towed over 13,500 ,so my statement may change if I do. But for now with the 68RFE, and the 13,500 I just wouldn't want to tow much heavier, big thing is getting it moving. Once its moving a bit ,then I can get into it okay.

With the Aisin and lower 1 & 2 I would probably be a bit happier, but getting into that throttle with that 13,500 and that 68RFE, its too much driveline shudder or whatever it is, its actually no different then getting into the throttle with my old 7.3 , it was slower moving ,but the same shudder.

Just remember you can back up a hill much better.....

 

[Cummins2014]

Just remember you can back up a hill much better.....

Well that gives me comfort, why didn't I look at it that way, then just going forward most of the time .

 

[6V92TA]

I always figured 373 was the best compromise.. 342 if you drive the thing for groceries, 410 if you don't give a crap about anything but how it pulls and 373 gives you a bit of both. LOL

I was taught that the best RPM range to operate a diesel engine under load was between torque peak RPM and the point where the Horsepower curve and the Torque curve met. I try to observe that rule of thumb even when I drive an automatic equipped vehicle

 

[kthaxton]

I always figured 373 was the best compromise..

Uh oh.....here we go again.

 

[SnoKing]

Uh oh.....here we go again.

Yep, 3.73's would be the wrong ratio for someone that wants to tow at 60 MPH. You would be lugging in 6th or turning un-need RPMs in 5th. Guess one can slow down and tow and 55 MPH in 5th.

 

[MarkEagleUSA]

Uh oh.....here we go again.

I think we need to know what gear lube and motor oil is used before making an informed decision.