RPM's when towing

[Mabrown]

I'm wondering how others tow. I tow a 9,000 lb fifth wheel with my 2002, 2500 auto with 3. 54 gears. I usually tow at 60 to 70 or so mph on the freeway in OD which is about 1600 to 1900 rpm's. At slower speeds or in hills or around town I turn off OD and run from 1900 to 2500 rpm's going about 50 to 65 mph. My question is is it good to tow for long distances at 2300 to 2500 rpm's?

 

[Shooter]

Your transmission will last a lot longer at up to 3k rpm in direct than lugging in OD. You should not tow in OD and if you do keep the rpm's above 2k.

Yes that means 75 mph or higher.

The CTD will pull all day at the governor, although it might be a little loud it won't hurt.

 

[Steve Campbell]

I agree....

<2000 not good..... >2000 Ok

 

[Snow man]

I agree with the others,keep it in drive,and let it wind out,no harm will be done. In fact your trans will last mucj longer,the only downsides are the noise,and fuel economy. As you are finding out the 3. 54 gears are not good for towing over 7K with an auto. OD is to tall,and it lugs,drive winds out a lot.

 

[Crazy Horse]

I agree w/ shooter. I did over 20,000 miles last year w/ a 2000 3500 CTD and auto trans. The truck was over GVW (12,000 lbs axle weight) the entire trip. The trans worked flawlessly!

 

[tarussell]

I have 4. 10's and I tow around 2800 RPM's all day long with no worry's. I do tow in O. D. but I never let the RPM's get below 2200.

 

[FAllen]

RPM

I understood from previous recommendations that <1700 was enough to provide sufficient line pressure in OD??



I'm sure that <2000 would be even better of course.



Fred

 

[RADdodge]

As I understand it, the magic number is peak torque which is a little over 1700 rpm on my ETC. On the newer trucks, the peak toque starts at about 1600. Under this and you're lugging it on a grade.

 

[RBSOB]

Around 2000

To some extent different trucks have different "sweet spots" but my auto with 3. 54s has OD off in really hilly or mountainous areas. Taller tires make "drive" towing much quieter [lower rpms] and pleasant Jim G.

 

[cwsoules]

The first time I went across the USA on I-40 I towed with OD off with my 4. 10 rear end we were at 2800 RPM much of the time. I tow at up to 62 mph. After my DTT modifications I now tow in OD above 57 mph (1700rpm) up to 62 mph my upper limit for towing. My DTT smart box down shifts out of OD at 57 mph.

 

[Steve M]

On the enterstate we tow in O/D 68-70mph at 1750-1850~rpm. If we're just easing along on flat ground I'll use O/D down to 45mph and 1250 rpm. If there's any work to be done such as a slight incline or time to accelerate, I'll lock out O/D. If we're towing in the hills and the speed limit is 55mph, I lock out O/D and run along at about 2250 rpm.

2500rpm all day long at full load is ok for the stock Cummins. I just don't care for the noise ten hours at a time. I had a '98 5spd/4. 10 and 70mph was 2500 rpm in 5th. It pulled great but man was it noisy! All day long... for days at a time...

 

[pwr2tow]

If your worried about line pressure, just put on a pressure lock from bd-power and once the transmission locks up you have full line pressures at any throttle setting, 3rd direct or overdrive.



Ron

 

[Prostock]

I tow a 3500lb car on an open trailer. If I am going 60mph and lock out my overdrive, the RMP's go up and it's like throwing an anchor out.



I don't understand how you guys do it at 2300rpm. My truck has lost it's power peak long before that.



Mine is a stock 94 auto, and I have 235/85/16 tires.

 

[Boldt's Wagon]

Prostock: Piers 3000 rpm governor spring kit will fix your problem.

 

[Barry]

Auto+4:10s+265/75/16s or 235/85/16s is 65 mph @ 2,000 rpm. Purrfect! If you have to have an auto, and you are running full size tires(265s on 2500s or 235s on 3500s) the 4:10s are just right for towing. DC finally came to their senses and dropped the 3:54/55s and the 3:73s are now standard. Not trying to start a forest fire but I have lots of customers driving both. I bought my Dad a '97 with auto and 4:10s and I installed 265s on his truck. It is an absolute delight to drive.

 

[Snow man]

I love my 4. 10's,and 285 tires,they are perfect for towing,we tow at 67-70 mph,which is 2000-2100,the motor sounds happiest when its at 2000+,when there's a trailer behind it.

 

[DIESELMAN]

Originally posted by Barry

Auto+4:10s+265/75/16s or 235/85/16s is 65 mph @ 2,000 rpm. Purrfect! If you have to have an auto, and you are running full size tires(265s on 2500s or 235s on 3500s) the 4:10s are just right for towing. DC finally came to their senses and dropped the 3:54/55s and the 3:73s are now standard. Not trying to start a forest fire but I have lots of customers driving both. I bought my Dad a '97 with auto and 4:10s and I installed 265s on his truck. It is an absolute delight to drive.

With those 3. 73's and new standard 265-70R16/235-85R16 the speed at 65 in an auto rises from 1700 RPM to 1800, and on a 5spd/6spd to about 1900 RPM.



The Auto is now at 73 mph @ 2000 and the 5/6 top gear is 70.



It seems a bit tall for towing and short for scud running on the freeway, but a certainly a better compromise than leaving the 3. 54's, the tires are not any taller than before.



Do you think this 100 rpm is enough to make difference?Oo.

 

[BLee]

My engine is stock. 3. 53 diff. See below for transmission mods. I towed my 13,700# fiver this weekend on OK & AR hills, mostly freeway/tollroads. Direct Drive (3rd) with the T/C locked up, 2500 RPM's, 64 MPH on cruise control uphill and downhill. 9. 9 mpg calculated. Pulled it almost 300 miles, and it acted like it was willing to go on forever. There's one really steep hill approching the campground, right after a stop sign. Put in in low gear, get up to 18 - 20 mph, lock the T/C in first, and just climb that hill! Felt like straight up! Sure is nice to lock 1st and 2nd when needed, not to mention the PacBrake. I got home with no brakedust on my front wheels. My son-in-law towed his smaller trailer and had red front wheels on his 1/2 ton F-150

 

[barkerdl]

How tough is it (or costly?) to change to 4. 10 gears on a 1992 model with auto and 2wd? Sounds like I might get a lot more service from an expensive transmission that way.



Dennis

 

[SlyBones]

I am with Steve M. Tow in OD on the interstate while its fairly level, maybe small inclines. Grades, hills, and curves all get OD locked out. -- Personally I dont see how people can stand the noise of 2500 rpms all day long.



Now that I have installed a DTT smartcontroller, there are a few other options available. I set it to downshift from 4th to 3rd at 55mph. Depending on the hill I just ease off the throttle let the speed drop, the SC does the downshift, I cruise the hill at 55. Once at the top I pick up the speed and back into OD it goes, automatically.



Another thing is I have gotten to like is towing with the PDR valet switch in valet mode. Does not have quite the top end power I would like ( gonna fix that ). I like the valet mode because it means really pressing down on the throttle. 1/2 and Full throttle to go up the inclines. I like this because with the smartcontroller's TC saver feature I can let in run it 4th unlocked. Depends on the incline of course, but sometimes I just put the foot to the floor and let the TC saver kick it out of lockup. The added increase in RPMs is just the right boost, and the efficient DTT TC seems to take it all in stride. This is a nice mode for smaller inclines. -- Larger inclines, long grades, hilly sections, lots of curves, get the OD lockout button and possible activation of full power mode.