Towing in OD or Drive for my 5th wheel

[kman522]

I know this conversation has been around forever, but while asking people what to tow my 5th in, I get about a 50/50 split on answers, so I am asking here.I have a 2001 Dodge Cummins, Quad Cab 4x4 with the 3.54 ratio. Only mod's to the motor are the SuperChip set to "tow-safe mode" and a K&N air filter. My 5th weights about #9500 and I dont tow my 5th under 55mph with OD. My problem comes in when I hit the interstate and run 65mph. My motor will scream if I leave it in Drive.What is the correct towing procedure??????

[Wulf]

I know this conversation has been around forever, but while asking people what to tow my 5th in, I get about a 50/50 split on answers, so I am asking here. I have a 2001 Dodge Cummins, Quad Cab 4x4 with the 3.54 ratio. Only mod's to the motor are the SuperChip set to "tow-safe mode" and a K&N air filter. My 5th weights about #9500 and I dont tow my 5th under 55mph with OD. My problem comes in when I hit the interstate and run 65mph. My motor will scream if I leave it in Drive. What is the correct towing procedure??????

I asked at the transmission shop here and he said not to tow in overdrive with my truck which is a 2001 quad cab 4wd sport. He said there is a part in the tranny when overdrive is selected that is stressed while towing.

[mohok]

Funny I should see this post as I was going to post the basically the same question. Quote from 2001 Owners Manual, "When to lock out over drive". "When driving in hilly areas, towing a trailer, carrying a heavy load, or whenever frequent transmission shifting occurs, press the O/D OFF button". I have towed approx 50k miles with my 2001 4 Speed Automatic at or near CGVW maybe a bit over sometimes with the O/D ON. I have 83k miles on the truck at this time. I say this with fingers crossed, I have not had any problems with my transmission at this point. What prompted me to consider doing a post on this question is that I talked with another 2nd Gen 1999 4 Speed owner today that was towing in O/D and had transmission problems around the 75k miles mark. He now tows with the O/D OFF and runs around 2k RPM. He stated that he gets around 10 - 12 MPG towing his 5th wheel with the O/D locked out. When I kick out the O/D my RPMs go from 1.6k to around 2k and it sounds like my engine is racing. I get 10 to 11.5 towing at 65MPHI see a lot of Motor Head talk on this forum and have extended my knowledge considerably concerning various aspects of RAM Truck maintenance and upkeep for which I am thankful. Will be interesting to gets some replies on what everyone else is doing out there with their 2nd Gen 4 Speed Autos while towing. MOHOK

[AH64ID]

I would use a trans temp gauge and pay attention to how often it shifts. If it's in/out a lot then lock it out.

[jlwelding]

I have a 05 with the 48 and am getting a deep trans pan with a temp gauge to be safe. My goose neck empty weights 7k. This is my first auto and dont like it just due to the fact of not knowing.

[Perrysburg Dodgeboy]

Unless the trans is hunting for a lower gear all the time leave it in OD. I tow a 10K TT and unless I'm pulling a steep grade I run in OD. I can climb the Jellico with the TT in OD no problem.Don

[flagmanruss]

I have 4.10 gears & OEM rubber... I know the owners manual says to not tow in OD. I didn't want to but the way I'm set up, the engine was screaming at highway speeds w/o OD. Until recently, when I added a Quadzilla XZT+ (2000 tune), the truck was not happy pulling moderate grades in OD (lugging). If I ran faster, I could get the engine into the power band I make the grades (now I can better pull those grades in OD, & if not I'm ok with dropping the speed a bit & shifting out of OD). Even with the XZT in "economy" mode the truck tows happier... I normally drive in econo mode & it is more peppy than stock (flip of the switch). I can only say what I've decided as a course of action for my own truck... I don't tow in OD on secondary routes with lower speeds. On the Interstates, I'll use OD if the rig seems happy with it. I don't jump on the throttle. I constantly pay attention & am prepared to shift down if it seems prudent.

[Mopar1973Man]

I know I'm a manual 5 speed but here is my 2 cents... I typically tow my 30' Jayco in 5th gear at 55-60 MPH with 3.55 rear end. But as soon as I can't hold 55 MPH I slip back to 4th at 50 MPH to protect the 5th gear nut issue. So now at 45-50 MPH in 4th gear I'm running right around 1800-2000 RPM's. When I leave home I find myself in 4th gear for quite a few miles because of the twisty windy roads around here. Once I make New Meadows Valley it pretty much flat and can pull in 5th for most everything. Why did I jump in the ring? Well 5 speed trans is really close to Auto. 4th Gear Auto 0.69:15th Gear Man 0.75:1 3rd Gear Auto 1:14th Gear Man 1:1 So when you push you OD OFF button you just the same as me in 4th Gear.

[kman522]

I'm like flagmanruss. I never use my cruise towing and I have a very light foot also while towing especially starting out. I use my OD ON/OFF button when going up a steep hill. I dont let my transmission lug either. I always take it out of OD when going through a small town or if the speed limit drops to 45mph for some reason. At about 55mph, I will hit my OD ON/OFF button and let it shift to OD. Any interstate driving, I use OD.

[MnTom]

I have been towing in O/D for about 8 years now with ZERO issues. The way I tow my fiver (CGVW 17k+) is to lock out O/D when I start out, then when I am in DRIVE at about 2250 rpms I reach up and turn on the O/D at the same time I let out of the throttle otherwise the turbo will bark something fierce! I have had to drop out of O/D due to a long (18 mile) hill, but other than that I will allow the rpms to drop to about 1500 PROVIDED it will pick up rpms fairly easily. If not I will go back to drive and the to O/D as described above.

[cajflynn]

I tow in OD with the cruise control on.

[fire176969]

I tow in OD also, although I have a TCC lockup switch to keep mine from trying to downshift. Have to pay attention to the RPM's though cause the trans will still kick down into passing gear even with the TCC locked by the switch. With my larger than stock tires though I am running about 2300 RPM at 65 MPH with the OD off.

[cajflynn]

I tow in OD also, although I have a TCC lockup switch to keep mine from trying to downshift. Have to pay attention to the RPM's though cause the trans will still kick down into passing gear even with the TCC locked by the switch. With my larger than stock tires though I am running about 2300 RPM at 65 MPH with the OD off.

The other problem with the lock switch is high egts when your rpm get too low.

[fire176969]

The other problem with the lock switch is high egts when your rpm get too low.

Yeah I agree. I really need to get gauges put in the truck before I kill something expensive. I normally just lock the TCC with the switch to get up to cruising speed and then turn it off to avoid just stomping on the pedal with it unable to unlock.

[Mopar1973Man]

Well after playing with ISX idea of keeping 2K RPM towing... Well I got to admit it works if you travel like 50-55 MPH drop down to 1:1 (4th gear - NV4500 or Drive - 47RE) the RPM's shot up and float right at 2K roughly but the pyrometer falls another 300*F and tows with better MPG's. I was truely shocked... I even tried it empty and yes it works on a empty truck climbing grades. But for flat ground you can run the top gear.

[cajflynn]

My name is not ISX.

[War Eagle]

Mopar1973Man, I see this post has talked about not only what gear to pull or not to pull in but also the mpg impact of that choice. I am interested in the mpg impact primarily and as I understand it, one of the best things to understand about the engine is the engine performance curves which include the BSFC chart. The brake specific fuel consumption for any specific engine is determined by dyno testing (on the engine only). It basically defines the fuel consumption over the gross operating range of the engine. I have included the performance curve for the gen 2 with VP44 pump. If you look at the BSFC curve you see it looks somewhat like a bath tub. The lowest end of the curve defines the most economical fuel consumption range for this engine. You can see that is is at or slightly above 2000 rpm. If you run above that rpm or below that rpm then you will experience more fuel consumption. Therefore, if you want the best economy you select the gear that will allow your engine rpm to remain close to 2000 rpm. Of course your gear selection along with your axle ratio and your tire size will determine what speed you will be traveling down the road at. As I understand it, even if your axle ratio and tire size allow you to pull in OD you may not be achieving the best mpg if you not at 2000 rpm. So you can shift gears up or down to get your rpm range at 2000 rpm and improve your mileage. So you may go faster or slower and you can improve you mpg. Now of course aerodynamic drag, rolling resistance, etc., will come into play also and it will have a negative impact on your mpg when you go faster (drag increases as the square of velocity) so even if you are pulling something that represents an increase in aerodynamic drag and you go 75 or 80 mph to get the engine turning 2000 rpm your mileage efficiency will likely suffer a heavy blow. In this case slowing down (to lower aerodynamic drag losses) will improve your mileage but as you slow down then your rpm takes you to a higher fuel conspumption point on the BSFC so if you again can select a gear that puts your rpm range back to the 2000 rpm you will again get to or near the optimum operating range of your engine and further improve your mileage albeit you will be going a slower speed. So it is not surprising to me that when you drove in 4th gear and kept your rpm range at 2000 then you saw an improvement in your mpg.

Dodge Ram BSFC Chart.pdf

[cajflynn]

There must be other factors at play because I get better mileage going 63 in overdrive at 1550 to 1600 Rpm's than I do in 3rd at 2000. I have found that I get the best mileage at 12 lbs of boost in OD vs 20 lbs in 3rd to maintain 2000 rpm's. It is also a lot quieter in the truck in OD!! Most of the stuff I tow I would have a hard time getting to 2000 rpm's in OD.

[Mopar1973Man]

My name is not ISX.

Yeah your right but want I was refering to was in another thread with ISX... But yes you've told me too...

There must be other factors at play because I get better mileage going 63 in overdrive at 1550 to 1600 Rpm's than I do in 3rd at 2000. I have found that I get the best mileage at 12 lbs of boost in OD vs 20 lbs in 3rd to maintain 2000 rpm's. It is also a lot quieter in the truck in OD!! Most of the stuff I tow I would have a hard time getting to 2000 rpm's in OD.

Thing is I live in a area where there is very little flat ground its either all uphill or all downhill. I'm battling to squeeze every last ounce of MPG's out of my travels like this is one of my better tanks of fuel in a long time I'm right now at 24.3 MPG I'm trying to beat my 25.3 MPG highmark then go for the big prize and beat ISX's 27 MPG which will be tough... So like going from my house (2,800 ft) to New Meadows, ID (4,000 ft) and McCall, ID (5,200 ft) I've got to climb 35 miles of highway. So if I just the set cruise at 55 MPH in 5th gear I watch my pyrometer float between 800-1000*F the whole way to McCall, ID Same thing from returning from Riggins, ID (1,800 ft) to home (2,800 ft) its a uphill battle with EGT's at about 800-900*F the whole way home. Now as for yesterday I done 2 trips to Riggins, ID (A/C Jobs). On my way down hill I would use 5th gear and set the cruise for 55 MPH EGT's float right about 500*F the whole way giving me roughly 30-32 MPG for that leg of the trip. Then on the way home I leav it in 4th gear and set the cruise at 53 MPH and surprise it dropped the EGT's from 800-900* to 600-650*F and show up home with 23-24 MPG for the return leg. Normally if I left it in 5th coming home it would be more like 19-20 MPG.

[fire176969]

There must be other factors at play because I get better mileage going 63 in overdrive at 1550 to 1600 Rpm's than I do in 3rd at 2000. I have found that I get the best mileage at 12 lbs of boost in OD vs 20 lbs in 3rd to maintain 2000 rpm's. It is also a lot quieter in the truck in OD!! Most of the stuff I tow I would have a hard time getting to 2000 rpm's in OD.

What gears/tire size do you have? In OD at 55 I'm running about 1250 RPM and about 1500 at 65.