Towing Question

[chazj]

My Dodge is a 2002 HO, 3:54 Rearend with a 6 speed manual. I currently tow a 10K trailer. When driving the speed limit in California (55) my RPM in 6th. is just under 1600 (the lower range of peak torque). In 5th. the RPM's jump to around 2200-2300. The latter certainly within the peak torque range of 505 ft. lbs.



While I don't have a sense that driving in OD is a problem with the Cummins, I am curious if there maybe some driveline issues I maybe facing in light of my lower RPM's? The difference in mileage using OD vs 5th. is approximately a Plus 2 mpg. However the fuel savings is not worth it should I be inadvertenly be damaging my drivetrain at the lower RPM's.



Any insight is appreciated.



Charlie

 

[SnoKing]

What I think you need to do is get the Governator to change the speed limit. It is a real pain going that speed. With my rig 2000 RPMs = 63 MPH, so running 55 I am to low in the RPM band. SNOKING

 

[mberry]

The main problem I see with this scenario is that you may be lugging the engine. If that is the case, you are doing more harm to your engine than to your drivetrain. You have two choices:



1. Increase your speed so you are above 1600RPM to avoid lugging the engine.



2. Run the truck in 5th gear. It certainly will not hurt your truck in any way to do that and you may even keep the same mileage or better since the engine is in a more efficient point in the power band.

 

[JKinney]

Charlie;

You just gotta watch the pyro guage. as long as the pyro temp is cool run in 6th but at 55 you need to get the rpms for any incline etc.

 

[HBarlow]

My previous truck was an '01 with drivetrain identical to your '02. All of last year and up until April of this year I pulled RV trailers from Pendleton, OR to the LA area and back north on I-5 in CA. I routinely set the cruise control and ran 59 or 60 mph and sometimes 62 which is my preferred towing speed. I couldn't tell you how many times CHP cars slipped up behind me and then passed or met me going the opposite direction. My impression, not factual information, is that CHP ignores commercial RV haulers and private RV owners unless your equipment or driving grabs their attention. CHP appears to be too busy with big trucks and cars driving 80 mph or faster. I'm not saying a CHP officer could not ticket you, just that they ignored me.



Harvey

 

[RColston]

IMHO the 24v does better at a higher RPM. I get a bit better mileage running around 1900-2000k. I typically tow 60-62 mph in 6th on flat ground or gentle rollers. Down to 5th for most everything else. I typically do not tow under about 1900 rpm. Our trucks are close to the same except I have a 3500 DRW CATCHER ECM, straight pipe and AFE stage 2 air filter.

 

[RustyJC]

My 2002 with NV5600 and 4. 10 rear axle has run many a mile towing our 5th wheel on the Interstate at 70 MPH (2350 RPM) with no ill effects whatsoever. The 4. 10 gears provide an additional 1500 lbs of GCWR, so I'd stick it in 5th and not worry about it.



JM2CW..... :-laf



Rusty

 

[WBlackburn]

I have an 01, 6 speed, with the 353 gears I tow a 34 ft Montana, weighs 14. 5 k all over the place. I generally run as follows:



If I am running a road that requires a speed of 55-59 I run 5th.

If i am running a road that requeirs a speed over that I run 6th, IF I'm not pulling hard.



I run the Edge EZ

 

[DiTrani]

I switched to 32" (235/85-16) tires largely for this reason. Now 55 in 5th is a bit more tolerable. Stock 245/85-16 tires are about 30".

 

[johncameron]

I do the same thing as you towing at those speeds. I haven't had any issues and don't expect any. I can keep my stock charger lit down to 1500 easy without any EGT issues on smaller grades. If I hit 6%+ grades I drop down to 5th to gain some airflow. If you are lugging your engine too low, you will have low boost and extremely high EGT's.



John

My Dodge is a 2002 HO, 3:54 Rearend with a 6 speed manual. I currently tow a 10K trailer. When driving the speed limit in California (55) my RPM in 6th. is just under 1600 (the lower range of peak torque). In 5th. the RPM's jump to around 2200-2300. The latter certainly within the peak torque range of 505 ft. lbs.



While I don't have a sense that driving in OD is a problem with the Cummins, I am curious if there maybe some driveline issues I maybe facing in light of my lower RPM's? The difference in mileage using OD vs 5th. is approximately a Plus 2 mpg. However the fuel savings is not worth it should I be inadvertenly be damaging my drivetrain at the lower RPM's.



Any insight is appreciated.



Charlie

 

[chazj]

I do the same thing as you towing at those speeds. I haven't had any issues and don't expect any. I can keep my stock charger lit down to 1500 easy without any EGT issues on smaller grades. If I hit 6%+ grades I drop down to 5th to gain some airflow. If you are lugging your engine too low, you will have low boost and extremely high EGT's.



John

I generally try to NEVER exceed 1200 degrees Pre-Turbo. When towing my 10K trailer at just under 1600 RPM in OD, my EGT's are around 1000 degrees.

 

[cwsoules]

When towing in California I tow at 62 mph, the speed the trucks use. With my automatic transmission in O/D my rpm is about 1900. I've used this speed when towing our 10K 5er for several years. I usually get 11 mpg.

 

[Andersonville]

Yep. You can run 60-62 mph in CA and the CHP won't bother you and make sure you obey the lane restrictions too. BIG FINES for lane violations.

 

[MLee]

Yep. You can run 60-62 mph in CA and the CHP won't bother you and make sure you obey the lane restrictions too. BIG FINES for lane violations.

The restriction of traffic or driving to slow will get there attention to. so the 58-62 fits better with there movement of traffic. Unless you run across an officer that has had a bad day, then its anybodys call.

It would nice to read a CHP's opinion on this subject, I know there are a few here but they probably won't comment because of the obvious. Just watch your rear if you exceed.

Marv.