Building a Tandem Axle Farm Truck?

[Cdnfireman]

This is good info.

Do you find they spend a reasonable amount of time in the intermediate gears?

I have an older Allison 6 speed.

They seem to want to get to 6th gear real fast.

I would say they spend little time in 6th and most of the time in 3-4-5 either accelerating or jaking to slow down. Realistically, most response speeds are between 65 to 85km/h. They can be programmed to shift differently as they hold gears longer if the jake is turned on. If the jake is off and the truck is just cruising, they shift in a similar fashion to a pickup in that they shift up fairly quickly.

 

[skegpro]

I would say they spend little time in 6th and most of the time in 3-4-5 either accelerating or jaking to slow down. Realistically, most response speeds are between 65 to 85km/h. They can be programmed to shift differently as they hold gears longer if the jake is turned on. If the jake is off and the truck is just cruising, they shift in a similar fashion to a pickup in that they shift up fairly quickly.

Thanks I'll have to test drive a properly setup one.

 

[lilduke]

Maybe you should wait and get a Tesla Electric semi. They haul ass compared to a diesel.

Just need a lil bit of a lift for around the farm.

 

[Cdnfireman]

Thanks I'll have to test drive a properly setup one.

Plus, on the keypad on the dash there’s a button for a different shift strategy and another to lock out 6th gear. I’m not sure what rear end ratio they have but they’re definitely geared for acceleration as they are governed to about 112km/h.

 

[arff]

FWIW, all our fire apparatus use the Allison automatics. The ladder trucks all weigh in at over 70k and rarely are there any transmission problems. And the trucks are not driven nicely at all. Full throttle starts, hard brake applications then hard on the throttle again. I’m amazed the transmissions stand up as well as they do.

Yes we abuse ours every shift. They are really tough.

 

[arff]

Plus, on the keypad on the dash there’s a button for a different shift strategy and another to lock out 6th gear. I’m not sure what rear end ratio they have but they’re definitely geared for acceleration as they are governed to about 112km/h.

I think the Mode button turns 6th gear on and off. I know on the qe2 we push it for the last upshift.

 

[007sevens]

So what would be the main benefit of having an 18 vs 13?

Other than being able to split the lower gears?

My 06 Pete runs 550 HP and 1850lbs torque 355 gears and an 18 double over 22.5 rubber. My 98 Kenworth runs 500 hp 1750 ins torque 395 gears and a 13 speed 24.5 rubber and quite often I wish I could spit the bottom. We pull super B's with them and quite often at harvest will have a good jag on leaving the fields. We dont however drive much further the just in the gate. While in bow low you have a **** tonne of torque, enough that wrecking the transmission is not my concern. I run light diffs because I'M THE ONE DRIVING IT. I won't abuse it. However if I was building truck for people to drive that dont/wont care about the truck I would run 46000lb diffs and your bullet proof in my mind. I'm no Pro with automatics and personally will not drive one, but I did witness a loaded fert truck flip after taking a corner to fast. I was told the jake didn't work as well with the auto. Not sure if this is true or not.

profesional claimer is that I hauled oversized farm equipment out of the states for 5 years.

 

[Trukker]

My 06 Pete runs 550 HP and 1850lbs torque 355 gears and an 18 double over 22.5 rubber. My 98 Kenworth runs 500 hp 1750 ins torque 395 gears and a 13 speed 24.5 rubber and quite often I wish I could spit the bottom. We pull super B's with them and quite often at harvest will have a good jag on leaving the fields. We dont however drive much further the just in the gate. While in bow low you have a **** tonne of torque, enough that wrecking the transmission is not my concern. I run light diffs because I'M THE ONE DRIVING IT. I won't abuse it. However if I was building truck for people to drive that dont/wont care about the truck I would run 46000lb diffs and your bullet proof in my mind. I'm no Pro with automatics and personally will not drive one, but I did witness a loaded fert truck flip after taking a corner to fast. I was told the jake didn't work as well with the auto. Not sure if this is true or not.

profesional claimer is that I hauled oversized farm equipment out of the states for 5 years.

Love love love splitten the bottom gear with 6NZ

 

[007sevens]

Love love love splitten the bottom gear with 6NZ

The Kittys are nice. This Truck has the ISX. When its works its alright, but there are issues with them.

 

[007sevens]

The ISX derates if you try to drive the bag off it with high revs. It encourages low rpm shifting and has more ponies down around 1000rpm then up at 1700. Im told the computer does a lot of thinking which is good if the computer hasn't been looking at porn and is full of malware.

 

[Stompin Tom]

What rear end ratios are guys running?

Got quoted a 4.11 and a 4.56.......

475 HP 1750 ft-lb at 1100 RPM

From what I gather reading inline I want to be able to cruise at 120km/hr at 1100-1200 rpm in 18th.......

My other concern is that I drive a metric **** tone of gravel rodes at 80 km/hr Soni also wanna be able to cruise that speed at the proper rpm.

I am thinking some of my concerns would be addressed with an 18 speed?

If you plan on only running a body job and will never tow anything then the Allison is fine, if your going to pull anything go with the eaton ultrashift. The Allison only has 6 gears, the Ultrashift has 18 so your much better off with a load.

Next, you NEVER want to cruise at 120 kmh at only 1100-1200 RPM, your will kill your motor, depending on the motor you choose. In a real world scenario you want your truck to run around 1400 rpm at 100 kmh. You will be able to bring it up to 120 kmh at about 1700 rpm. No reason to ever go faster than that. Gravel and lower speeds are no big deal, just a lower gear.

Depending on tire size, if your using 11R22.5 tires I would go 3.55 to 3.73 gears, and with 11R24.5 3.90 would be a good choice.

 

[Stompin Tom]

The ISX derates if you try to drive the bag off it with high revs. It encourages low rpm shifting and has more ponies down around 1000rpm then up at 1700. Im told the computer does a lot of thinking which is good if the computer hasn't been looking at porn and is full of malware.

I have run ISX and cummins pretty much since about 2003, I have no idea what you mean by "derates if you try to drive the bag off it with high revs" but frankly you dont drive any commercial diesel with "high" revs. If your running an ISX no reason to ever go over 1700 rpm even if they are governed at 2000-2100. The peak torque range is 1250 to 1600 rpm and peak torque right in the 1250 range and peak horsepower at 1600-1700 with a severe drop off after that.

 

[the_real_wild1]

I have run ISX and cummins pretty much since about 2003, I have no idea what you mean by "derates if you try to drive the bag off it with high revs" but frankly you dont drive any commercial diesel with "high" revs. If your running an ISX no reason to ever go over 1700 rpm even if they are governed at 2000-2100. The peak torque range is 1250 to 1600 rpm and peak torque right in the 1250 range and peak horsepower at 1600-1700 with a severe drop off after that.

I think he is talking about programming. It can be adjusted so when you hit 1500 or really whatever number you enter the engine will fall flat. Three of the international lease returns I am cleaning up have it programmed in. They came out of the east. They can be a pain to drive if you like to rev them higher.

 

[007sevens]

I have run ISX and cummins pretty much since about 2003, I have no idea what you mean by "derates if you try to drive the bag off it with high revs" but frankly you dont drive any commercial diesel with "high" revs. If your running an ISX no reason to ever go over 1700 rpm even if they are governed at 2000-2100. The peak torque range is 1250 to 1600 rpm and peak torque right in the 1250 range and peak horsepower at 1600-1700 with a severe drop off after that.

I guess derates is a bad choice of words what I was referring to is Load Base Speed Control.

LOAD BASED SPEED CONTROL (LBSC)
The first feature that impacts your driving the ISX is Load Based Speed Control (LBSC). This feature works in gear 1 thru 8 only. It was designed to encourage drivers to shift through the gears quickly, and at low RPMs. Under normal or light demands on the engines, LBSC is designed to limit the engine RPMs to its most efficient range. The ISX engine is most efficient when operating at 1450 RPM. The engine is least efficient when operating at or near 1800 RPM when shifting up through the gears. The ISX is programmed to limit RPMs to 1500 in gears 1 – 7 and 1600 in gear 8 when there is a low power demand on the engine, i.e. when operating on flat terrain or with empty or lightly loaded trailers.
If the engine is demanding high levels of power in these gears, the operating range will be extended to 2000 RPMs. While it is understood that the engine will NOT be operating in its most efficient range, there are situations where drivability would be impacted severely by limiting the operating range to lower RPMs. Examples include entering an interstate highway via a steep on-ramp or climbing steep grades.

 

[007sevens]

I think he is talking about programming. It can be adjusted so when you hit 1500 or really whatever number you enter the engine will fall flat. Three of the international lease returns I am cleaning up have it programmed in. They came out of the east. They can be a pain to drive if you like to rev them higher.

Thats exactly what Im talking about. I think this engine that I have has something programmed into to it. I bought it a couple years back as an x highway tractor. I think it came from the east as well however it looks way to clean for a road salted truck.

Is it much of a problem to clean up the ECM's on these trucks. I deleted mine and have been chasing issues since I bought it. It had a cracked head so did a complete inflame. Found out shortly after the turbo actuator was stuck at 70%. threw a new one on. Then I couldn't get it to hold boost while at 100% load. Found that the Exhaust manifold sensor had a pin rotted off. Pulls like a freight train now but I still feel the jake should be better. I only see about 23lbs boost while braking. not sure what the spec should be. Its defiantly not as strong as my N14 I ave in the other truck.

 

[the_real_wild1]

You can get stuff adjusted but need to find a guy that knows what each setting will do. And even then it takes time as you have to make an adjustment or two then test drive, adjust and driver etc. I haven’t been into a Cummins dealer program in years so not sure what they have access these day. I know I had literally hundreds of adjustments I could make with my laptop at the last dealer I worked for. With the fleet programs I can’t adjust many things. Just the basics.

 

[skegpro]

If you plan on only running a body job and will never tow anything then the Allison is fine, if your going to pull anything go with the eaton ultrashift. The Allison only has 6 gears, the Ultrashift has 18 so your much better off with a load.

Next, you NEVER want to cruise at 120 kmh at only 1100-1200 RPM, your will kill your motor, depending on the motor you choose. In a real world scenario you want your truck to run around 1400 rpm at 100 kmh. You will be able to bring it up to 120 kmh at about 1700 rpm. No reason to ever go faster than that. Gravel and lower speeds are no big deal, just a lower gear.

Depending on tire size, if your using 11R22.5 tires I would go 3.55 to 3.73 gears, and with 11R24.5 3.90 would be a good choice.

Are you running an automated 18 or manual?

I am leaning towards the automated 18 but it scares me.

So the are quoting me a 4.56:1 rear with 11R22.5 tires

That rear end tire combo seems way out to lunch...........

 

[Stompin Tom]

Are you running an automated 18 or manual?

I am leaning towards the automated 18 but it scares me.

So the are quoting me a 4.56:1 rear with 11R22.5 tires

That rear end tire combo seems way out to lunch...........

456's with 11R22.5s? You better find a different dealer! You will have a hard time maintaining 80 kmh with that set up. I run 4.30 with 11R24.5 in an industrial application hauling 63500kgs. With 4.30's I am about 1550 rpm at 100 kmh.

I run a manual 18 speed but know lots of guys with the ultrashift and it has really improved, to the point that I am considering one in my next truck. In your application I wouldnt have any concerns at all. The base tranny it self if by far the best on the market and the ultrashift has the bugs worked out.

 

[Stompin Tom]

Thats exactly what Im talking about. I think this engine that I have has something programmed into to it. I bought it a couple years back as an x highway tractor. I think it came from the east as well however it looks way to clean for a road salted truck.

Is it much of a problem to clean up the ECM's on these trucks. I deleted mine and have been chasing issues since I bought it. It had a cracked head so did a complete inflame. Found out shortly after the turbo actuator was stuck at 70%. threw a new one on. Then I couldn't get it to hold boost while at 100% load. Found that the Exhaust manifold sensor had a pin rotted off. Pulls like a freight train now but I still feel the jake should be better. I only see about 23lbs boost while braking. not sure what the spec should be. Its defiantly not as strong as my N14 I ave in the other truck.

I get around 36-38 lbs of boost with my ISX, 550 hp 2050 tourque. One way to find out if your jake is working properly is to watch your boost guage when you toggle your jake. First leave your jake on stage 1 and you should get no boost while jaking, then set it on stage 2 and you should get 10 lbs or so boost, then try stage 3, you should get over 30 lbs when jaking hard at 1700 or 1800 rpm.

 

[Stompin Tom]

You can get stuff adjusted but need to find a guy that knows what each setting will do. And even then it takes time as you have to make an adjustment or two then test drive, adjust and driver etc. I haven’t been into a Cummins dealer program in years so not sure what they have access these day. I know I had literally hundreds of adjustments I could make with my laptop at the last dealer I worked for. With the fleet programs I can’t adjust many things. Just the basics.

a good programmer can make a world of difference, out local dealer has a couple of guys who are great with the electronics. They will go for a test drive with you with laptop hooked up, watch your driving style, make a few changes and the engines really perform after that.