Towing in overdrive

[cplanner]

Joined recently and still feeling my way around this TBR site. I read where some tow with overdrive engaged and then I read to always take it out when towing as does the owners manual. I tow a 5er and have always turned OD off. Confused? Need advice.

I have a 2002-2500 GC, Stock engine, 139"WB,47RE Auto, 4. 10 Ratio:

 

[DMcGalliard]

Always tow in OD

Hi Cplanner,

I have a 98/24v/3500/with auto and 4. 1 and mods to engine and tran. I don't see how you get any where in 3rd with a 4. 1 I have pulled a 14k 5th wheel 50000 miles most of it in OD. No lugging, usually get up to 50-55 before letting the tran shift into OD. Can pull most hills on the East Coast except Black Mountain on I40 in NC. Pull at 65-72mph, try for 2200rpm is about 68mph. I found that the stock defuels in 3rd gear. stock OD is stronger than 3rd.

Try OD.

Davem

 

[kluther]

i keep overdrive off until 55-60 mph. even a little higher towing a 5-ver. then leave it until you drop down under 55 and take it back out of o/d. so far so good ken PS it's TDR

 

[cwsoules]

The first trip to the East Coast from California on I-40 I towed with OD off. The truck was stock then. On the way home I tried to tow in OD on flat land and would lock out OD when the transmission shifted out. After finding this site I tried to keep OD off until I got up to 57 mph where rpm was over 1700.



I wanted an exhaust brake as I found that on down grades over 6% the entire rig would accelerate, cruise control would disengage the transmission and all I would have is brakes to slow the rig.



I got the DTT modifications and now have good control up and down mountains.

 

[Steve M]

I use O/D when there's no headwinds or hills. If it'll pull in O/D with at least a little power to spare, you should be ok. If you're running with your foot to the floor and not accelerating but just maintaining speed, you're lugging which can lead to burned pistions or valve seats. Installing a device to increase fuel so you can tow at a low rpm that you couldn't run at stock is forcing the motor beyond it's designed rating and will increase your chances of doing damage. I only have two choices with my auto/3. 54 towing on the interstate at 65mph. O/D at 1750rpm or 3rd at 2500rpm. If it'll pull in O/D with some reserve power I use O/D. If not, 3rd has alot of reserve power at 2500-2700rpm at peak horse power. If your automatic transmission is downshifting too much it's trying to make a decision for you. It's time to lock out O/D and enjoy the power of a Cummins at peak HP.

Hot rodders don't take offence. I love to see a Dodge Cummins light up the tires and outruns 5. 0 Mustangs. The fact is, the more power you turn out the more likely something is going to break. That's not rocket science, just the simple facts of high performance. I can easily afford some performance mods. I just can't afford the possible consequences.

 

[Blakers]

I pulled my 5500 lb. travel trailer through the mountains of West Virginia on a recent trip to Tennessee at 65-70 mph with the cruise on. Most of the time I hardly knew the camper was there. Only a few times did I have to either back off the throttle a little or take it out of OD to keep the EGTs below 1200 deg. It has 3. 54 gears and runs about 1800 rpm at 70 in OD.

 

[CPG]

Hi Planner,

The amount of weight that You haul or tow & the terrain dictates the use of overdrive. Our trucks vary so much its hard to state just what is the best for all of Us. Out here in the west We have lots of mountain terrain. My truck is a "93" first gen. and I pull a 8500 lb. 5vr. I usually use O. D. on the flats at 1700 RPM. When I get to a grade as soon as the tach needle starts to drop, I lock it out of O. D. Its mostly a case of common sense and watching Your tach. You can feel Your truck if its lugging. I do not let it drop under 1700, but the newer trucks with more HP can do better. Wind factors also determine a lot on Your selection here. Your 4. 10 axle ratio is an advantage in the mountain driving. Hope this helps.





Chuck Goode

 

[cwsoules]

I also watch my EGT, Turbo Output Pressure, and transmission termperature. You can detect the increase in load on your transmission in OD by looking for a rise in transmission temperature. I will also shift out of OD early when I see the load increasing.

 

[Big-D]

I also have 3. 54 gears and run without being in OD. I've found that setting the cruise control to 2450 RPM's in 3rd gear locked up with DTT upgrades has provided consistently satisfactory mileage and cool temperatures. Even though I am a few MPH under the posted speed limit I've found using the cruise control relaxing and a lot less stressful. I don't have to worry about my speed and the engine doesn't vary going up grades either.



My choice of using OD occurs with trailwinds, flat ground and speeds above 70 when towing. Otherwise, 3rd gear purrs all day long.

Dave