M1078 model year changes

[redman333]

What are some of the major or even minor changes that happened to these from year to year. Ive been trying to narrow down a range of years I'm looking for but have had problems finding out what years had what equipment and what changes.

1.It looks like in 2000 they went from a mechanical motor to the 3126 electronic engine.
2.in 05-06 they went to the C7
3. in 07 they changed the trans control unit so not sure if the trans is different
4. At some point they made a change to the fuse panel

Anything else that you can think of. Also they if you know what the change on the trans was, that would be helpful also.

Here you can see the trans display double digits like the earlier wtec1 I believe it was.


It looks like this could be it, says its for a wtec 2


This is the fuse panel

 

[Rebuilder]

Lots of info here.... https://en.wikipedia.org/wiki/Family_of_Medium_Tactical_Vehicles

 

[redman333]

Lots of info here.... https://en.wikipedia.org/wiki/Family_of_Medium_Tactical_Vehicles

Been there, from what I can tell the engine info is correct based on the site at least but I cant find any info on the trans. Or any other changes.

 

[NDT]

1997 is WTEC 2, 1998 is WTEC 3.

 

[branr1]

At some point there was a change to the rear differential, I believe that the rear differential is now the same as the intermediate axle on the MTVs. This has greatly reduced the drive line angle.

 

[wandering neurons]

Rear air brake chambers changed in 1997 into 1998.

 

[BKubu]

The door hinges were changed on the A1s, but I don't recall what year. The A1s have additional grab handles on the outside of the cab, which are nice. The A1s (at least my 2007...not sure what year they started it) have different bumpers.

 

[wandering neurons]

Oh yeah! The door handles and locks. Also the interior door panels to match.

 

[scottmandu]

C7 was installed 2004 to present.
3126 was 1999 through 2003.
up 10 1998 was 3116
WTEC 2 was installed through 1997, but earlier trucks could have been updated
WTEC 3 was 1998 to sometime in the middle of 2005
Gen IV was mid 2005 to present

2007 model year saw the different rear axle. Either in 2006 or 2007 the lower part of the front bumper was changed from a steel plate to fiberglass.

The exterior grab handles were added with the C7 and the door handles were changed at the same time. However since doors are easily swapped you may see different handles on earlier trucks.

The cab airbags were deleted with the C7. The door handles were flipped sometime in the 2000 model year. In mid 2002 the battery disconnect switch was added.

 

[fuzzytoaster]

C7 was installed 2004 to present.
3126 was 1999 through 2003.
up 10 1998 was 3116

Though the 3126 was made until 2003 it did end up in 2004 produced A1 units (I've got one). Otherwise your info is on point.

 

[frank8003]

1997 is WTEC 2, 1998 is WTEC 3.

Allison explained
http://blog.diesellaptops.com/2016/10/06/allison-transmission-generation-models-explained/

 

[scottmandu]

Though the 3126 was made until 2003 it did end up in 2004 produced A1 units (I've got one). Otherwise your info is on point.

It could be a running model year change or production difference for the various models, I've seen a couple 2004's with the C7 but didn't pay much attention to the serial numbers.

 

[redman333]

C7 was installed 2004 to present.
3126 was 1999 through 2003.
up 10 1998 was 3116
WTEC 2 was installed through 1997, but earlier trucks could have been updated
WTEC 3 was 1998 to sometime in the middle of 2005
Gen IV was mid 2005 to present

2007 model year saw the different rear axle. Either in 2006 or 2007 the lower part of the front bumper was changed from a steel plate to fiberglass.

The exterior grab handles were added with the C7 and the door handles were changed at the same time. However since doors are easily swapped you may see different handles on earlier trucks.

The cab airbags were deleted with the C7. The door handles were flipped sometime in the 2000 model year. In mid 2002 the battery disconnect switch was added.

So it looks like if I wanted the most updated truck is be looking for a 2007 or newer. I don't really care about the change in the bumper much so then 2005 and up for me. I'd like to have the general 4 trans and maybe the C7 cat. I haven't decided whether I want the 3126 or the C7. If I decided I want the C7 I will pretty much be getting all the other upgrades as well.

Question though. Can the cab air bags be added easily to the models with the C7 in them. Seems strange they would remove them.


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[scottmandu]

Question though. Can the cab air bags be added easily to the models with the C7 in them. Seems strange they would remove them.

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I believe it is possible to retrofit the bags but have not done it. The bags were deleted as a cost savings measure and the acert C7 runs quite a bit quieter and smoother than the 3126 and the 3116.

 

[redman333]

I believe it is possible to retrofit the bags but have not done it. The bags were deleted as a cost savings measure and the acert C7 runs quite a bit quieter and smoother than the 3126 and the 3116.

That would make sense. That's good to know that the C7 is quieter then it's predecessors. For that bit of info alone I may Target those models.


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[319cssb]

One of the major differences is the fact that early cabs and truckbeds were not galvanized. These trucks had holes from rust whilst they were sitting at the Sealey plant waiting to be installed. The DoD made Stewart&Stevenson give a 10 year warranty on the cabs and fix damages. Most were patched with panels where they rusted through. mainly under the steering column and the roof line. That went on until in 1997 all trucks have finally been all galvanized. That's one of the major differences I know...

 

[fuzzytoaster]

So it looks like if I wanted the most updated truck is be looking for a 2007 or newer. I don't really care about the change in the bumper much so then 2005 and up for me. I'd like to have the general 4 trans and maybe the C7 cat. I haven't decided whether I want the 3126 or the C7. If I decided I want the C7 I will pretty much be getting all the other upgrades as well.
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As a general rule of thumb yes but later production A1's are few and far between. The 1081A1 that was basically brand new from the factory with all the trimmings and was a non-runner sold for 20K + fees at auction. You'll find an earlier A1 much easier though still uncommon compared to the "A0" trucks.

...acert C7 runs quite a bit quieter and smoother than the 3126 and the 3116.

Having dealt with Holt Cat a bunch recently on my 3126 I picked the shop supervisor's mind about this topic. He says the 3116 is ok but parts and service is getting harder to find. Once they have fuel system issues then they go down quickly usually resulting in the need for new injectors (they tend to blow seals and back pressure the fuel system). The 3126 is supposed to be hardy and less maintenance intensive to the 3116 but it's at the top of its hp rating for the injectors installed. The C7 is the same block with different injectors etc.. for more hp but more emission compliant. I agree with you they are a smoother engine but the supervisor said they have a higher rate of injection pump failure forcing metal bits into the engine and it's all down hill from there.

 

[redman333]

As a general rule of thumb yes but later production A1's are few and far between. The 1081A1 that was basically brand new from the factory with all the trimmings and was a non-runner sold for 20K + fees at auction. You'll find an earlier A1 much easier though still uncommon compared to the "A0" trucks.


Having dealt with Holt Cat a bunch recently on my 3126 I picked the shop supervisor's mind about this topic. He says the 3116 is ok but parts and service is getting harder to find. Once they have fuel system issues then they go down quickly usually resulting in the need for new injectors (they tend to blow seals and back pressure the fuel system). The 3126 is supposed to be hardy and less maintenance intensive to the 3116 but it's at the top of its hp rating for the injectors installed. The C7 is the same block with different injectors etc.. for more hp but more emission compliant. I agree with you they are a smoother engine but the supervisor said they have a higher rate of injection pump failure forcing metal bits into the engine and it's all down hill from there.

Almost all heui systems are bad for this. Oil changes and extra precautions pertaining to keeping the oil system clean will go a long way in keeping the fuel system good. Also on the C7 cat issued a later revised doc that has an update that adds a oil filter to the oil supply line to the heui pump to catch any last bits of debris that might get in. I've heard a lot of bad things about the C7 and almost all the complaints are due to the fuel system and while I don't know a huge amount I do know if you keep the oil clean the pump lasts a long time. I've seen it personally on customers vehicles.


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[redman333]

As a general rule of thumb yes but later production A1's are few and far between. The 1081A1 that was basically brand new from the factory with all the trimmings and was a non-runner sold for 20K + fees at auction. You'll find an earlier A1 much easier though still uncommon compared to the "A0" trucks.


Having dealt with Holt Cat a bunch recently on my 3126 I picked the shop supervisor's mind about this topic. He says the 3116 is ok but parts and service is getting harder to find. Once they have fuel system issues then they go down quickly usually resulting in the need for new injectors (they tend to blow seals and back pressure the fuel system). The 3126 is supposed to be hardy and less maintenance intensive to the 3116 but it's at the top of its hp rating for the injectors installed. The C7 is the same block with different injectors etc.. for more hp but more emission compliant. I agree with you they are a smoother engine but the supervisor said they have a higher rate of injection pump failure forcing metal bits into the engine and it's all down hill from there.

A1 models being 2000-2004? Correct. Still learning the model designations.


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[coachgeo]

If you want the CATs meow at a logical price (pardon the pun)..... buy the newist A0 you can get. Remove engine and replace with engine of your choice. Keep in mind you might need to go mechanical /non computer engine so you don't have to figure out how to get engine computer to talk to the Allison's computer. The A0's 3116 with no engine computer, does not talk to the Allison's computer so less software/hardware headaches for engine swapping in an A0.

For all I know though some computer engines can be fitted in a way to not talk to a tranny computer.... I've no experience in this.