Medium duty engine/tranny?

[Flashman]

Who/what/how is this rating awarded?

[ShinerBock]

Bionic Man wrote:

And, as said, to the best of my knowledge, all the engines in medium duties are de-rated vs their less commercial cousins.

Yes, they are, but it is mainly to meet emissions certificates rather than heavier duty cycles like most think.

[Bionic_Man]

I am not an expert on this (nor do I care if something is labeled as "medium duty), but I am under the impression that the definition has to do with duty cycle. If that is the case, then just because an engine/transmission is used in a "medium duty" truck, that does not necessarily mean that it is a medium powertrain.

And, as said, to the best of my knowledge, all the engines in medium duties are de-rated vs their less commercial cousins.

I do find it humorous (although not surprising) that many that throw that term around are unable to clearly articulate what it means.....

[ShinerBock]

Flashman wrote:
Being the Op - let me rephrase the question.

Which engine/tranny combos offered in our puny little pickups can be considered medium duty.

I do not care if they are used in other applications.

Also where did the average engine overhaul at a certain mileage come from??

All three engine/trans are available in medium duty(class 4-6) vehicles. The Aisin/Cummins is found in the Ram 4500/5500, the Allison/Duramax is found in the GMC 4500 cutaway Van, and the Torqshift/Powerstoke is found in Ford F450-750 trucks. If someone tries to say that only their's is then they are just showing their ignorant bias just so they can feel special about their pickup.

Although technically the F750 is not a medium duty truck and is actually a heavy duty truck based on its max GVWR of 37,000 . So technically the only trans/engine combo available in pickups that is heavy duty is the Torqshift/Powerstroke combo. The Torqshift/Cummins used to fill that role.

[6_6_Oilburner]

Flashman wrote:
Being the Op - let me rephrase the question.

Which engine/tranny combos offered in our puny little pickups can be considered medium duty.

I do not care if they are used in other applications.

Also where did the average engine overhaul at a certain mileage come from??

The answer is none. Lesser horse versions of the engines were/are used in Medium duty Apps. If you want to blur the lines. Every engine found in a diesel pickup from 2001 up was used in medium duty applications in some variation.

[Cummins12V98]

Flashman wrote:
Being the Op - let me rephrase the question.

Which engine/tranny combos offered in our puny little pickups can be considered medium duty.

I do not care if they are used in other applications.

Also where did the average engine overhaul at a certain mileage come from??

Cummins/Aisin.

[Cummins12V98]

4X4Dodger

In Columbus the 6.7 either gets black paint or red paint! Red is for Freightliner's and black is for ALL RAM's from 2500's thru 5500's.

The Cummins 6.7 "IS" a true Medium duty engine.

[Flashman]

Being the Op - let me rephrase the question.

Which engine/tranny combos offered in our puny little pickups can be considered medium duty.

I do not care if they are used in other applications.

Also where did the average engine overhaul at a certain mileage come from??

[blt2ski]

That classification system and trucks involved is not totally.correct at least from a GM standpoint. If the 5500 is older std cab, that giver went from 19,500-26000. SAME as the 6500. The 4500 was the.class 4 and 5 rig with giver from 14000-19500.

The Allison trans, the 1000 is good to 19500 giver and iirc 30000for gear. The 2000 series.in.Two.different gearing options, with or with out a parking pall, went from 19500-26000 giver with the pall, to 33000 without a pall. Gear was 30k with, 40k or so with out. These two options GM wise wee only.in the 25-55 series. The 6500 and higher had the 3000 series trannies. That series.got you.up into.The 60-100k gvw range. Higher hi p.and torque.input.rating too.
One will find this with all the manufactures.
Engine wise, the 5.9 uric had around a.dozen or so 😛 options from 160-300 :-P. Two emergency service options to 360 hp or so. Some manufacture had low hp with higher torque options, and 20 or so hp/torque options, depending if you are powering a rig for giver, or for the.potential gcw it may.run down the.road. or if it will be.A.city.or hwy rig.
Way more to.This than medium, heavy.or.light.duty rated.

Marty

[4X4Dodger]

zb39 wrote:
I believe the RAM 6.7 is, I know the 5.9 was. Check at the TDR web site.

The above are NOT Medium Duty Trucks. The Engines/Transmissions may be used across categories but if they are in a light duty truck it is still considered light duty. See Below: Source Wikipedia.

"In the United States, commercial truck classification is determined based on the vehicle's gross vehicle weight rating (GVWR). The classes range from 1–8. Trucks are also classified more broadly by the Department of Transportation's Federal Highway Administration (FHWA), which groups classes 1–3 as light duty, 4–6 as medium duty, and 7–8 as heavy duty. The United States Environmental Protection Agency has a separate system of emissions classifications for trucks"

Medium duty
Class 4

The Class 4 truck gross vehicle weight rating (GVWR) ranges from 14001–16000 lb (6351–7257 kg). Examples of vehicles in this class include the Ford E-450, Ford F-450, Dodge Ram 4500, and the GMC 4500.

Class 5

The Class 5 truck gross vehicle weight rating (GVWR) ranges from 16001–19500 lb (7258–8845 kg). Examples of trucks in this class include the International TerraStar, GMC 5500. Dodge Ram 5500, and the Ford F-550
Class 6

The Class 6 truck gross vehicle weight rating (GVWR) ranges from 19501–26000 lb (8846–11793 kg). Examples of trucks in this class include the International Durastar, Chevrolet Kodiak/GMC TopKick C6500. and the Ford F-650

[JustLabs]

Flashman wrote:
I was under the impression that the 6 speed manual tranny in my Dodge was medium duty ??

In Europe,the G56 is used in trucks up to 60K GVWR

[Flashman]

I was under the impression that the 6 speed manual tranny in my Dodge was medium duty ??

[Bedlam]

I'll even through another wrench at these guys that claim to running MDT power trains in their LDT's: The tuning is different. The 6.7 PSD is tuned to 300 hp for MDT applications and the 6.7 CTD is tuned for 325 hp. Those are specifications if plan to work your engine its entire life and still get reasonable life out of it. The cranked up tunes in the pickups are great for bragging rights, but bad for longevity.

[rjstractor]

Like others have said, virtually all of the big 3's diesel engines have been used in medium duty applications, and many for vehicles of over 26K. There is obviously the Cummins B engine, but the International versions of the 7.3,6.0 (yes even that motor) and 6.4 engines have also been used in medium duty and bus applications of up to around 32K GVWR. The 6.6 Duramax used to be in the "light" medium duty Kodiak trucks but I'm not aware of any MD applications that motor is in now.

[Cummins12V98]

Cummins in Columbus, IN builds the 6.7 for RAM and Freightliner on the same assembly line. The only real difference is the adapter that mounts to the back of the engine that the trans will mount to. Oh and the Freightliner engines are painted red.

The Aisin is used by other manufactures in Medium Duty applications.

Ford uses their trans in the 650/750's now. The Allison they used to use was NOT the same trans as in the GM trucks. The 6.7 Cummins they used to use was the same as the RAM Cummins.

Someone can correct me but I have a fiend with a Kodiak and he says his Allison is different then the ones offered in the pickups. Other Allison applications like motorhomes can be different also.

[blt2ski]

To be a bit more specific, some also has to do with how long a motor will last before a complete rebuild. IE 400-600K miles vs 200K. BUT, still that is suspect in my mind, as Navistar had V8 diesel motors with equal mileage before rebuild as GM/Ford had the BB gas rigs back in the 90s, all had a 100K mile useage's. IE the IDI6.9/7.3 motors Navistar in mdt rigs, and Ford used in pickups and the SD350, before the current 450 chassis came out. My idi7.3 has 20 years and 140K, its on its last legs, but still usable. If one wanted a higher miles before rebuild, one went with a DT360/466/530 which had 400K lifetime expectancy if used city driving, 600K if more on the freeway. The T444E and subsequent 6.0, 6.4 V8's had 400K mile useages as the B5.9 and DT360 had. But lighter in weight, approx same hp for like useage.

But, I would agree with bedlam and some others, that it is not used as it should be per say by some forum members.

Marty