A0, A1, A1R and TM's

[Third From Texas]

C7's can have black or yellow valve covers according to my sources. Mine is black.

Serpentine modification kit NSN's:

2815-01-533-1324
2815-01-533-1308

No idea how common it was to install these. But they existed at one point.

I had to look. I needed to raise the cab today anyway. LOL

Mine is black

 

[GENX]

Mine is black too.

 

[fuzzytoaster]

I had to look. I needed to raise the cab today anyway. LOL

Mine is black

View attachment 872094

FML - LMTV
FMM - MTV

"Fun" tid-bit of info on these serials. They're produced under "military/emergency services" serial range which causes CAT dealerships some trouble. HOLT CAT here in Texas has multiple licenses and their departments don't intertwine. When my first A1 had a failed ECM, their truck division was logically my first choice. They didn't have the legal ability to program an ECM due to the serial range. I was directed to their Power Services division (gensets, pumps, etc) and they could program it but didn't want to as it was a vehicle . I had to stir the pot some and eventually Power Services came through which their labor rates and etc were cheaper too. Oh the fun we have with these trucks.

 

[Third From Texas]

Here’s the gauge panel.

If you look on GP (you can search sold items as well) you can see the three variants of the dash (A0, A1, A1R). They are each unique to the variant.

 

[GeneralDisorder]

https://www.mouser.com/ProductDetail/Honeywell/NSCSSNN150PDUNV?qs=C%2F0tY%2F%2FqZe9ewEwKCB2V2A%3D%3D

This seems to be the replacement recommended by Honeywell for that deprecated pressure sensor. From what I can ascertain from the DataSheets, looks to be compatible?

Yeah I've looked at those exact pages..... The SX150D operates at 12v. That replacement operates at 5v and I had thought that would make them not compatible but upon looking at the data sheet it appears the replacement will operate at nominal 5v but up a max of 12v so yeah I think this could work! I'm going to order a few to fix my extra MMDC's! Thanks for the prod to look at the data sheets closer!

 

[GeneralDisorder]

Yea, those look like the digital gauges, look for the MMDC box under the drivers dash, about eye level while standing on the ground when you open the door. Like In Generals pics, has 2 small airlines running to it. I suspect your power panel has 4 black modular relay/fuse boxes inside it. A1 variants notwithstanding, I believe you now posses what most would consider an A1R… R stands for Race, or “R” your pockets deep enough… Congratulations

It is not an A1R. That is the WTEC 3 transmission control and he stated it has the 100A alternator. The A1R would have the 260A alternator and the WTEC 4 transmission.

GENX - you have a late model A1...... A1R schematics are incorrect for your model..... you have something that's a hybrid of sorts. A1 with the C7, WTEC 3, MMDC..... what's your truck serial number?

 

[Johno176]

You installed a BRAND NEW MMDC? Or a "good" used one? I have not experienced what you describe. I would swap the air lines and see if the other gauge acts similarly to rule out some kind of supply pressure issue to the unit. If it stays with the same gauge after swapping the air lines front to back I would say you have a second bad MMDC. Every unit I have bought "surplus" has exhibited the same transducer failure issue. One of them legitimately had 35 miles on it and already had a bad transducer. These trucks sit and the air systems don't get drained leading to rust and moisture and any of that gets into the transducers and it kills them. Very poor design IMO that didn't account for the conditions these trucks experience in the real world.

It was a brand new MMDC unit. Right after I installed it I had the same random read outs on the same tank gauge. It would either read normal or show a reduced pressure reading. I will try swapping the air lines to see if it shows up in the other gauge.

 

[Ronmar]

GenX, What does the power panel look like? Got a pic of the front shock absorbers?

General, what exactly does a wtec4 control head look like?

 

[GeneralDisorder]

GenX, What does the power panel look like? Got a pic of the front shock absorbers?

General, what exactly does a wtec4 control head look like?

Here's a PDF that goes over the different generations of WTEC. The "3" has a single digit display, while the "4" has a double-digit display. The "5" (which is not seen on FMTV's AFAIK) has a double digit display with a wrench icon between them.....

https://assets.wellertruck.com/reference-materials/owners-manuals/fourthgenshift-selector-manual.pdf

Page 13 details the WTEC 4.

Page 19 details the WTEC 3.

A true A1R would have the 4.

 

[GENX]

Serial
A-T101564BGFR

The dash has 4 black boxes containing relays and breakers. (I think 4….From memory, I have cab tilted now.)

Front Shock

 

[Ronmar]

Well the MMDC and the 4 relay boxes indicates an R’s wiring but that unsprung shock does not indicate an R chassis, so you do appear to have a tween truck. Based on the 4 box PP I suspect the R wiring diagram does apply to you though…

 

[Ronmar]

Here's a PDF that goes over the different generations of WTEC. The "3" has a single digit display, while the "4" has a double-digit display. The "5" (which is not seen on FMTV's AFAIK) has a double digit display with a wrench icon between them.....

https://assets.wellertruck.com/reference-materials/owners-manuals/fourthgenshift-selector-manual.pdf

Page 13 details the WTEC 4.

Page 19 details the WTEC 3.

A true A1R would have the 4.

I have a friend who has an R(coil springs and all) and his has a 3 control panel. They were kind of sloppy with their version changes weren’t they

 

[GENX]

So it appears this upgrade is out on my chassis:

Upgraded Air Spring Cab Suspension Kit For LMTV & MTV

Shop the Upgraded Air Spring Cab Suspension Kit for LMTV & MTV at Midwest Military Equipment. Direct replacement with a higher load rating and easy installation. Made in the USA.

midwestmilitaryequipment.com

 

[GeneralDisorder]

You do not have the air ride cab? You should..... I wouldn't think they ever produced a non air ride without coil spring shocks..... The coil springs were to support the armored cab upgrade and that's also when they deleted air ride.

 

[coachgeo]

So it appears this upgrade is out on my chassis:

Upgraded Air Spring Cab Suspension Kit For LMTV & MTV

Shop the Upgraded Air Spring Cab Suspension Kit for LMTV & MTV at Midwest Military Equipment. Direct replacement with a higher load rating and easy installation. Made in the USA.

midwestmilitaryequipment.com

maybe you can get the parts form one of the parts strippers to convert it to air ride. A0 hoop and cab latch system.... granted the A1 cab latch may be able to re-used. Might even be an upgrade? Hydraulic hoses etc to go to it along with fittings to go to manifold if your A1 is different fittings (or fab in a mechanical release instead of hydraulic??)

 

[GENX]

See pics.

 

[Third From Texas]

Yeah, that's a later A1 . The A1R would have the giant coil-over front shocks and no air ride. So you're sort of in-between models there. Score on the C7 though.

I bet it rides well w/o air ride. The only thing that makes the A1R's a bit stiffer is the coil over. Air ride is OK but lots of things to to wrong and they squeak like all hell. I've often wondered what my truck would run like with normal shocks replacing the coil overs.

 

[Third From Texas]

So it appears this upgrade is out on my chassis:

Upgraded Air Spring Cab Suspension Kit For LMTV & MTV

Shop the Upgraded Air Spring Cab Suspension Kit for LMTV & MTV at Midwest Military Equipment. Direct replacement with a higher load rating and easy installation. Made in the USA.

midwestmilitaryequipment.com

As Geo said, that's just the airbag replacement. There's a TON of other bits that make up the system. You'll spend thousands to make it a squeaky cab. LOL

 

[Third From Texas]

You do not have the air ride cab? You should..... I wouldn't think they ever produced a non air ride without coil spring shocks..... The coil springs were to support the armored cab upgrade and that's also when they deleted air ride.

That is curiously cool, huh.

It it sort of makes sense. The cab was never intended to be up-armored so the coil overs are totally unnecessary until you reach the P2.

Never seen this configuration before.

I like it.....

 

[Third From Texas]

dbl post