school me on towing

[DFranks]

TV 06 2500, rebuilt transmission, with billet single TC/billet piston. cutom VB with Gm Solenoid, TS shiftmaster control. I run a smarty S06 on 60hp to tune only.

CAI,Big exhaust for breathing. 285 70R17E tires



OK, Question is , when I pull my TT 34. 5' 9000lb TT in the rockies, I notice that my transmission (in T/H) will hold OD even under 1500RPM, is this ok? or should I manually shift to keep above this. I have heard anything under 1500rpm for these 5. 9's is a no no, but to try and keep as close to 2k as possible. Yes, it does feel like it is lugging... . If I turn the smarty down to #1 it seems worse because it doesn't have the power #3 with TM does.

I have even contemplated going back to the 265's that came on the truck, maybe that would put the 373's back to 373 ratio.



My Egt's have never seen above 1400F while towing.

Just want to make this the best TV I can have for this setup.



thanks for any and all input.

 

[Bob4x4]

Neither your fuel milage or transmission will be happy towing that load on a grade at 1500 rpm. Let it run in it's comfort zone

 

[CKelley1]

it is not good for the engine. it shows up in beating out the bottom half of the rod bearing. i can not stand a auto but i can tell you how to drive it. when loaded you select the gear,never let the auto do it the sweet spot on your 06 is 2000 rpm at highway speed try to stay about 1800 rpm when you approach a grade shift to a lower gear to give you about 2200 to 2400 rpm if it starts to pull down from this drop down another gear. when you desend a hill drop to a gear that you can keep about 2700 rpm with out touching the brakes. if you do not have an exhaust brake get a bd. this will help emensley.

 

[HBarlow]

A Cummins published book titled: "Operation and Maintenance Manual ISB Engine" I bought in '01 when I bought my first Cummins-powered Dodge instructs drivers to approach a steep grade at full throttle in top gear and allow the engine rpm to fall to but never below maximum torque rpm which should be 1600 rpm with your engine.

If you observe that your engine doesn't have adequate power to maintain 1600 rpm back off the throttle and manually shift down to third/direct or even second gear if required then put your foot back in it.

 

[Ram4Sam]

A Cummins published book titled: "Operation and Maintenance Manual ISB Engine" I bought in '01 when I bought my first Cummins-powered Dodge instructs drivers to approach a steep grade at full throttle in top gear and allow the engine rpm to fall to but never below maximum torque rpm which should be 1600 rpm with your engine.



If you observe that your engine doesn't have adequate power to maintain 1600 rpm back off the throttle and manually shift down to third/direct or even second gear if required then put your foot back in it.

Interesting quote/info. This is pretty much how I tow my 5er (10,000 lbs+/-) whether in the Sierras or up and down the flatlands in Ca. This gets me the best mileage, performance and egt control.



Sam

 

[HBarlow]

Interesting quote/info. This is pretty much how I tow my 5er (10,000 lbs+/-) whether in the Sierras or up and down the flatlands in Ca. This gets me the best mileage, performance and egt control.

Sam

Yep, you apparently have a good feel for the capability of your Cummins engine and figured it out on your own. The Cummins book was published to provide guidance for the reasons you stated.

Downshifting and revving the Cummins engine before starting up a grade generates higher horsepower, allows faster ascent, but burns more fuel. Higher rpm probably is easier on our light duty transmissions.

 

[EricBu12]

a 9000# trailer is not too heavy. . that is why you are able to hold 1500. . yet it should shift down one. this will allow you to speed up uphill and get over the hill faster.

I have the 68RFE and I let the engine lug down to 1600-1700 then shift. for my 36' 15K trailer this does pretty well. . I have gone down to 4th gear revving up to 2400 rpm.

A rule of thumb for climbing is if you push the throttle and it don't accelerate at all, shift down. A rule for going downhill is descend the hill in the same gear you climbed up it. . Same steepness. .

 

[DFranks]

Thanks for the responses!



I will make the transmission shift, from now on.

 

[RonD]

Try this the next time you tow, when you expect a grade will cause the engine to RPM down to 1500, take it out of Tow Haul prior to the climb, then when it gets below 1650 RPM's hit the TH button, it will drop into 3rd, or maybe 2nd, mine likes 1700-2200 the most, low RPM's are not great for the engine under a load.

 

[DFranks]

Try this the next time you tow, when you expect a grade will cause the engine to RPM down to 1500, take it out of Tow Haul prior to the climb, then when it gets below 1650 RPM's hit the TH button, it will drop into 3rd, or maybe 2nd, mine likes 1700-2200 the most, low RPM's are not great for the engine under a load.

That's a great idea, I am heading out this weekend I will try that too.

thanks

 

[Skydiver]

My on view of why I never LUG an engine. Just as a water skier can skim on top of water, our main crankshaft bearings ride on a thin layer of oil. Take away the speed and the water skier sinks, just as the crankshaft will. When a crankshaft falls out of its layer of oil it meets the main bearing.
Never lug an engine. More rpm, more oil pressure. Our engines turn slow enough already.

 

[DFranks]

Thanks, I never thought of it that way. That Makes complete sense,