How much weight towed with a 98.5-01 Cummins dually?
 

Long story short, I purchased a 1998.5 24 valve dodge dually with a 5 speed trans to tow my 40ft enclosed. I just moved my car from NY to N.C. and through the hills the truck was a dog. I had to down shift to 3rd to pull some hills at 40mph. Truck runs like a top boost right around 25 lift pump pressure never below 12 when pulling up hill hard. I am guessing my trailer was weighed down pretty heavy, probably about 16k. The truck is stock minus a cold air intake and 5” exhaust.

I feel the truck should have more power. I have talked to some people and they agree with me, I have also talked to some people that say that’s really heavy and I should look into upgrading some hard parts before a tuner ie: intercooler, turbo, injectors.

I am just looking for some real world experience with how much people have towed to find out if I have something going on or that’s the way they are. Anybody with some insight I would greatly appreciate it.

Re: How much weight towed with a 98.5-01 Cummins dually?
 

Check the gear ratio in the rear. My buddy has a 98 and it has a 3.55 gear in the rear. It’s a bit soggy on hills. He pulls a 40 ft goose that is fairly heavy. What size tires on the truck?

Re: How much weight towed with a 98.5-01 Cummins dually?
 

Obnoxious tires from previous owner 285/75/16
Trying to sell them as I type this

I read it was a mix of gear ratios, I’ll have to check. Cruising 70-75 I know the rpms are at about 2100 in 5th gear. I did get 19mpgs empty

Re: How much weight towed with a 98.5-01 Cummins dually?
 

Billy,
I just sold my 2002 3500 last year, a couple differences in my truck it was a 6 speed and had 4.11 gears and was a 2wd, same engine as yours. I had it for 10 years and pulled a heavy 48 ft LQ trailer. One of the first things I installed was an electric fuel pump to increase the lift pump pressure to 24 PSI, and installed a Edge Juice with Attitude tuner and a non restricted exhaust. The tuner in towing mode was like a different truck, and would pull hills without issue. Everything else was bone stock including the air filter. I bought it with 49K and sold it with 119K. Fuel mileage pulling the trailer was 12 MPG, no trailer 19 MPG.

Your lift pump pressure is too low, and if the VP is not damaged it could be. If the turbo is in good shape, I would invest the money in a tuner, before hard parts other than a pump to get the VP happy. I ran a Holley blue pump as the lift pump and adjusted the spring to increase the pressure. I replaced the Holley pump 2 times as it would start leaking fuel at the seal, but worked without issue and served the purpose to get fuel to to the VP.

Sean

Re: How much weight towed with a 98.5-01 Cummins dually?
 

Thank you for the reply sir, the lift pump is aftermarket. It’s a fass lift pump and the vp44 was replace about a year ago I was told. Usually when cruising it’s about 20 from the lift. About 12-15 over big hills. I am looking into a tuner.

But it towed your 48ft pretty good?

Re: How much weight towed with a 98.5-01 Cummins dually?
 

Your welcome!
I never had an issue with pulling grades. Yes it pulled my 48' trailer without issue. I always ran stock size tires too. The tuner was like night and day on power output.

Sean

Re: How much weight towed with a 98.5-01 Cummins dually?
 

Great, I did find out I have 3.55 gears. So I’ll look into swapping them to 4.10s and purchasing a programmer and go from there. Thanks again I appreciate it.

Re: How much weight towed with a 98.5-01 Cummins dually?
 

Depending on which DANA you have there is a a 373 available little more gear than the 355 but not as tall as a 410 you get a little more pulling power but fuel mileage doesn't get totally killed either

Re: How much weight towed with a 98.5-01 Cummins dually?
 

I might be wrong but I think the 3.73 is for the rear end that replaced the Dana in the D3500 turcks. I think the brand is "American".

Re: How much weight towed with a 98.5-01 Cummins dually?
 

You most likely have a Dana 80 rear end. Try contacting a company caked Diesel Power Prodhcts they list many gear ratios for that rear from a 3.55 up to a 5.13 see what they say the r&p prices are around $300 or so depending on the gear you select. Small parts are available to complete the installation --- I have no experience with this company but I'm sure you can find reviews on themFED 387