Cummins Diesel Forum banner

Truck has trouble towing 7000 pound trailer?

8K views 27 replies 13 participants last post by  Mopar1973Man 
#1 ·
Hello all,

I have a 1999 Ram 2500. I also have a 26ft camper that with all our stuff weighs about 7000 pounds. On flat roads this truck pulls it just fine, but whenever we encounter a slight grade of any kind we either have to speed up before we get there and try it while slowly slowing down or turn overdrive off and trudge up the hill at 2,800rpm. Considering the manual says this truck can pull upwards of 12,000 pounds I'm having a hard time understanding why I'm having this issue.

Thanks.
 
#3 ·
Are you sure the camper only weighs 7000 pounds and not 17k?

7K is a small trailer.


You didn't mention what type of camper it was so figured I'd toss that in... Just trying to help!
Thanks but yea it's just a travel trailer(no slides unfortunately). I believe before adding water to tanks or propane or anything the trailer weighs 5500 pounds. Then with liquids and all our stuff it's about 7k.
 
#4 ·
OK 1st, you aren't supposed to tow a camper in overdrive.

2nd, 2800 rpm would be lugging a gas engine and in comercial applications these same engines run at 2400 rpm allll daaay looong. Offshore boat turn them up to 5000 rpms.

How fast will it pull that grade if you do pull it at 2800 rpm?
 
#7 ·
I don't know why your mentioning gas engines b/c that's pretty irrelevant here. 2. If you do any research online it's perfectly fine for diesels to be in overdrive when cruising, maybe not so much for gas, but for diesels yes. If I remember correctly with overdrive off at 2800 it's at about 55-60(on interstate with 70mph speed limit.
 
#5 ·
Back up...do you have any gauges ?
What is your boost psi ?
What are you egt's ?

Even unloaded, i have seen some grades that i had to hold a steady rpm to ascend.
 
#6 ·
OK 1st, you aren't supposed to tow a camper in overdrive.
Why not? I do all the time without an issue (5th gear 0.75:1 ratio). I pull an 31' foot RV in the mountains of Idaho with no issues at all. As for my setup I've done quite a bit of modifications to my truck power wise. Here is what I'm towing... These truck will pull a good sized trailer with little issues if setup right.



OP could you fill in your signature so we know what we are dealing with truck wise.
 
#8 ·
If I remember correctly with overdrive off at 2800 it's at about 55-60(on interstate with 70mph speed limit.
Automatics (Overdrive OFF) is the same as 4th gear on NV4500 or 5th Gear on NV5600 they are all Direct Drive (1:1 Ratio). So that being said at 55 MPH with 3.55 gears, stock 265's tires you'll be right around 2,100 on the tach. In overdrive Its .68 for auto, .75 for NV4500 and .73 for NV5600. Very little difference but it will drop down to about 1,600 at 55 MPH. As for towing I will use direct gear for climbing grades because puts more torque to the ground. Then once back on the flat ground I'm using 5th gear.
 
#10 ·
What size tires ?

A stock truck with a stock automatic/convertor and 3.55 gears is pretty doggy. If bigger then stock size tires just makes it even worse.

In stock form with an automatic 4.10 makes a big difference.
 
#11 ·
Really, none of us can answer you unless you give more information.
If your truck is 100% stock, then being a slow dog is normal.
If you do a few relatively simple things to it, and one really expensive one (a real transmission), it'll pull gangbusters.
Or at least it should. If you set it up properly and it still doesn't pull, then troubleshooting can begin.

But like I said, if it's dead stock, then of course it's slow!
 
#12 ·
Truck is completely and utterly stock. Don't really like the idea of changing things(and spending money) given the age of the truck. My point is that for towing a relatively small load for this truck it's acting sluggish. I mean if I keep it in overdrive going 65mph over a small hill and it can't keep up, then I have to completely floor the truck in order for it to downshift to go up the hill.

And like I said everyone I haven't taken this up any mountains, these roads I'm talking about are just small general hills down in the southern USA.
 
#13 ·
Is this truck new to you? IE has this truck ever towed like you think it "should"?

Sounds to me like you have a stock 2nd gen trying to tow in OD.


Boost levels when this happens?
egts?
Fuel pressure?

any codes?

All key pieces of information we need.
 
#14 ·
Well then that's the problem.
These things aren't tuned for much power dead stock. The engine can handle lots more. The automatic transmission, in stock form, cannot.

Everyone will tell you, there's pretty much a standard to-do list to make decent pulling power, reliability and mileage.
First, a few gauges so you know what's going on. Fuel pressure is the first one I'd get. The other standards are boost, pyrometer, and trans temp. Lack of adequate fuel pressure will kill your injector pump. You need to know if you've got enough. The stock pumps are notoriously bad.

A mild tuner such as an Edge EZ will really wake it up, without being too crazy.
However, the stock automatic is the big weak link. Your truck NEEDS to be slow and sluggish so as not to wipe out the stock torque converter and trans.

That's just how it is.
 
#15 ·
Remember these trucks were built before today's speed limits. You might just be disappointed in the downshift from OD. From time to time, you are going to have to drop it out of OD when pulling, even with only 7k lbs. When it drops back a gear the RPM's can be startling, but consider that it's because speed limits are higher than they were in the late 90's. We tend to drive 'em faster than the transmissions were set up for. The newer 6-speed automatics actually have 2 overdrive ratios but our transmissions only have one.

Running RPM's in the mid to high 2000's isn't going to hurt anything in my opinion. It sounds radical with our noisy engines but it's not that hard on them. I have a manual tranny (NV4500) and I drop out of 5th when pulling grades just to protect the weak 5th gear in that particular transmission. I typically slow down to keep the 4th-gear RPM's around 2500 if it's a long grade.

Also consider the effect of altitude (you didn't mention if you are pulling at altitude). If you are pulling at altitudes above 5,000 feet, the turbo has to build a bit more boost and the engine can seem like it's working a little harder.

Now... If you drop out of overdrive and it's still having trouble pulling 7k lbs at 55mph, you might have a problem.
 
#17 ·
That's true about the speed limits thing. Truck does tow fine when not in over drive, just sounds like it's screaming like you mentioned. If you look at my other post you'll see that I'm in southern USA. The areas I've pulled with this truck haven't gone over 500ft alt. so that's not a factor.

I just don't understand why I have to absolutely floor the truck in order for it to drop out of overdrive if I haven't already disengaged it.
 
#18 ·
Go to orielly/autozone and borrow an oil pressure gauge. Test your fuel pressure and report back, it needs to be at least 10 psi at all times according to dodge, but we like to see above 14psi to keep fuel flowing through the overflow valve.

Check for boost leaks, I am sure the truck has them if you have never checked before. Fix them.



HOWEVER the truck only has 235 hp 15 years ago...ie 180 hp now days. It will take revs to keep it moving while towing. your revs NEED to stay above 1800 rpm when towing, likely 2200, min, is where you will have to keep the revs in order to tow. OD + towing +stock != good things.
 
#26 ·
HOWEVER the truck only has 235 hp 15 years ago...ie 180 hp now days. It will take revs to keep it moving while towing. your revs NEED to stay above 1800 rpm when towing, likely 2200, min, is where you will have to keep the revs in order to tow. OD + towing +stock != good things.
This is true.. I asked the very same question a couple weeks ago. Rpms need to be up in the 2000+ range to maintain speed climbing. But for me.. with 285s that means traveling at a speed of ~75mph to do so... which is above the speed spec of the travel trailer tires.
 
#19 ·
I have plenty of power with a small BD Van Aken chip, somewhere 50 to 90 hp upgrade. It does not hurt the automatic. What hurts automatics is too much power and lead foot launches and not using gears properly. Over 250k on clutches and 500k on hard parts before only stripping an output spline on a hard take off after hard core 4x4.
 
#20 ·
Don't let these guys scare yo from using OD. I ran over 263k miles before transmission broke in my 02 Dodge 2500 Ram (Cummins). Don't let every one freak you out about OD. I never had a problem with towing using OD (5th gear NV4500). I live in the mountains of Idaho and tow lots and lots of mountain grades most highways are 6-7% most forestry grades can be 12-16% grades. As for Automatics yes they are weak but most of it can be upgraded. A good aftermarket valve body and good torque converter can make a world of difference in towing. I've got a 96 Dodge 1500 Ram with a 46RE and use it for towing as well as using OD. Again smart use of gear will get the mileage out of the transmission. As for the 96 it wore the OEM torque converter out at 162k miles at that point I had Dynamic rebuilt the transmission and that is one strong transmission now and tows wonderful even on OD.
 
#24 ·
Don't let these guys scare yo from using OD. I ran over 263k miles before transmission broke in my 02 Dodge 2500 Ram (Cummins). Don't let every one freak you out about OD. I never had a problem with towing using OD (5th gear NV4500). I live in the mountains of Idaho and tow lots and lots of mountain grades most highways are 6-7% most forestry grades can be 12-16% grades.
FYI, I broke 5th gear in my nv4500, sheared two teeth off. The trans had been rebuilt when I bought the truck (at unknown mileage) and I ran the truck for 80k miles before it broke. Pulling 12k foot passes in the Colorado Rockies, but with no more than 4,000 lbs in tow. Now I don't know if it was due to strain or due to worn out bearings, I've heard bearing wear can cause gear breakage. But I've been gentle on 5th ever since.
 
#21 ·
"if I keep it in overdrive going 65mph over a small hill and it can't keep up, then I have to completely floor the truck in order for it to downshift" indicates this isn't a manual, it's an auto.
 
#22 ·
Towing heavier in OD with an automatic is not going to be the same as towing with a manual. Different experience and results. Nonetheless, it kinda sounds like to me that the TV cable may need to be re-adjusted because I dont believe mashing all the way to WOT shouldn't be necessary for the transmission to drop out of OD. :thumbsup:
 
#23 ·
I dont believe mashing all the way to WOT shouldn't be necessary for the transmission to drop out of OD.
As for TV cable adjustment they should move together at the same time from resting position. Using a flashlight you should be able to see the TV arm and move thebellcrank for the throttle and see if it pull at the same time. If not readjust the cable taking out the excess slack. Some add just a touch of pull to it to cause it to downshift earlier.
 
#25 ·
Making the engine crank more power is easy.
The ugly-truth answer is there's no inexpensive way to get an automatic '99 to tow strong and live to tell about it.
If you're going to remember to drive it like the transmission is the weak link you can probably get by on just a decent single disc converter and a better valve body and save a bunch of $$ over a fully built trans.

When turbo diesel pickups first became popular in the '80s and early '90s they had no power. The big-block gas trucks ran circles around them. (Well except for the Dodges because Chrysler had stopped making 440s). The automatic transmission's biggest problem in a diesel was ever getting going from an uphill stop. More than once I had to back down the wrong way on a busy street with a trailer because the old Ford 6.9/auto just wouldn't make enough oomph to pick itself back up.
Then they started cranking up the power. Everyone I knew who had one, and all our trucks at work, started blowing out auto transmissions. These things weren't originally set up to take 600+ ft/lbs.

I'm a little new to owning Dodge trucks, I'm an old Ford and Chevy guy who has worked with trucks for 30 years. It doesn't matter what brand, this same issue affected all of them.
I'm sayin', until beefing up the trans is in the works, just keep that truck slow if you don't want to spend a bunch of money.
 
#27 ·
These engines are just too small to ask it to tow anything decent in size/weight under 2000 RPM. You can move along a flat freeway pretty easily if the weight and wind resistance is low enough, but anything other than flat and the drivetrain is taking a beating and usually EGT's start to skyrocket.
 
  • Like
Reactions: Mopar1973Man
#28 · (Edited)
with 285s that means traveling at a speed of ~75mph to do so
If you tow often, oversized tires are not your engine and transmission friend... They add a lot of rolling resistance and enhance the beating that the transmission will take. This is not point at dodgedieselnewbie per say but just a point of reference. Drag and loads (rolling resistance and rotational mass) have to be consider highly for trucks that are planning on towing often.
 
  • Like
Reactions: dodgedieselnewbie
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top