M1088 project, no start. Not even trying!

[FloridaAKM]

You gotta love those trucks from Ft Bragg. They treat them so well, always service them correctly, change out broken parts & assemblies. Then when they are sent to DERMO, it like getting a vehicle that was previously owned by a little old guy down the street who loved his vehicle.

Not.

Good luck with your truck as you go thru it & fix what ails her. Lots of info & experience on what to do here if you read & ask.

 

[snowtrac nome]

The throttle cable may need some adjustment. Alot of trans issues are low voltage either weak batts or the alt is not charging. It wont let you downshift into a gear that would cause over rev while moving. Sometimes you just need to run it hard to get the trans going again. Post a pic of where you think something is missing.

sounds like its stuck in limp home mode get some one with Allison doc to plug into it and pull codes. also look at data funny thing I had an engine in protection mode the other day it also had the Allison locked in limp mode.

 

[f8617]

...another missing component. It came off of the rear air tank and looks like there is a 2 prong wire terminal that goes to it. It was right above the regulator that comes out of the bottom of the same tank.

sounds like you're describing the wet tank pressure switch for CTIS...but connector is 3-prone w/ 2 wires.

 

[thetruckguy]

Ha ha ha FloridaAKM! exactly! they robbed this thing blind of parts!

Here is the pic of the missing part. It screws into the elbow and the wire plugs into it. I'm guessing a pressure sensor, but not sure what it controls.

I will check into the limp home mode, but the display showed normal operation. When it first started, it shifted firmly into gear, both drive and reverse. But after warming up, it didn't want to go right into gear. At the time, the foot brake was acting up though too. I know most trucks with Allison transmissions have a safety feature that won't let it go into gear without pressure on the foot break. Maybe that had something to do with it, or maybe that sensor is required for the Allison to work properly.

In a minute I will add the pic for the transmission id plate I found. looking it up as we speak to see what I can learn.

definitely though, Suprman, that emergency glad hand check valve is definitely one of the problems, so I am going to fix that first.

 

[thetruckguy]

 

[thetruckguy]

really hard to read

 

[Suprman]

The part is ctis pressure switch. I have one.

 

[thetruckguy]

No kidding? That must be why my CTIS box has all the lights steady on. How much you want for it?

 

[NDT]

You do not have to press the brake to shift the Allison. Did you have any codes showing on the WTEC?

 

[thetruckguy]

No, no codes.

 

[Suprman]

You need to run the snot out of that truck and it should start shifting ok. Make sure you are getting full gas pedal travel. Take it up on the highway and run it wide open to 57 for a few miles. Make sure your fluids are right before doing this.

 

[thetruckguy]

I fired it up today, and checked the voltage, had 14 and 28. Brakes seemed to work a little better, and I was able to start out in 1st gear. I guess the default starting gear is 2nd or 3rd, but I manually turned it down to 1st before I started moving. It inspected kinda hard doing it manually, but it went all the way up to 7th. Made a weird noise at 7th, and I ran out of runway. As I turned around to head back it jumped from 1st to 3rd and would not sift again. I kept trying for the mile back to the shop, and finally it shifted again as I was ready to pull in. So I decided to floor it any keep going. Manually shifted it up to 7th again, and back down to 1st, turned around and repeated it for a couple miles. In high 6th and 7th it made a weird noise like a tire with really deep lugs.

 

[Suprman]

First is low range. Keep it out of mode and low unless you are off road. You should be able to put it in drive and give it full throttle to run from 2-7. The 2-3 shift is a wide ratio.

 

[thetruckguy]

That must be why it jumped out of 1st when I was turning hard on hard packed millings. Good to know. I have to figure out why the fuel is loosing prime after I shut it off. I don't want to keep using either to start it. I believe it is the primer bulb. Also, right now I am jumping the auxiliary starter solenoid. It starts fine that way, but it is a pain in the butt. The starter button works but there is a short I think. It acts like I am repeatedly tapping the starter button as fast as I can. I don't want to ruin the starter.

 

[Suprman]

Replace the hand primer filter head they go bad

 

[thetruckguy]

Also, I tried doing the Allison self diagnostic, and when I pushed both arrows it flashed D13312. I did it with the engine running, in neutral.

 

[Suprman]

I think thats sump oil temp sensor. Dont think it would cause bad shifting but you never know. Is the speedo smooth or jumpy?

 

[thetruckguy]

Speeds is smooth

 

[Suprman]

You need to adjust the throttle cable so you get full throttle. There is a threaded rod where the cable meets the fuel pump. Make sure the cable moves smooth. Sometimes you need to disconnect the cable and re route it in the engine bay so there isnt tight bends in it. Then drive it. Especially if its been sitting. Try a good 5 mile drive then see how it shifts around town. The 2-3 is always going to be a bit jerky.

 

[thetruckguy]

OK, I will give it a shot