Towing a dead M1083 with M1079

[JRKJeeper]

I’m having an inoperable 1083 dropped off about 3 blocks away in a dead mall parking lot so we can get it off the lowboy. I have to pull it with my 1079 back to my property. In the TM under towing disabled vehicle it still says turn it on and hit neutral. But this thing is an actual disabled vehicle. So it can’t be turned on or run. Does the trans need air to shift to neutral? Or can I hook up my slave cable and see if it powers up enough to hit N. I have the cables and hoses to connect the two with the towbar. But I can keep the brakes caged if the back truck won’t hold air pressure. I figured there would be such a procedure for an actual dead truck and not just one that doesn’t start.

 

[chucky]

Youve got to have air lines from 1079 back to 1083 to air up its system and release brakes or you have to cage the parking brakes and hopefully you have a towbar ment for these trucks if its only 3 blocks and you dont get over 15 20 mph i dont beleave you will mess anything up but only cause its so close to home if not either pull the axles out with 3/8 threaded bolt and mark which one went where to go back the rite way or drop the u joints at the front diff and the middle dif front of chunk and tie the drive shafts up to frame real good ! And dont worry about lights just have someone to follow the trucks home to sheild the idiots !

 

[Ronmar]

Neutral engages the C5 clutch in the transmission. I have not specifically determined what the C5 clutch does for you in neutral… now I do know that Allison does not like to switch more than one solenoid pair at a time. IE: using pulse width modulation, they roll off one, while simultaneously rolling on another to help maintain stable pressure During a shift. C5 is in the mid transmission group, and it is used in both D and R. Putting it on in Neutral would be an obvious step to prepare to shift into D or R and you would only be engaging one other solenoid valve to shift into 2 or R… with the exception of shifting down into first, all of the other shifts only effect one of the 2 solenoids currently engaged to shift from one gear to another. C5 is only used in the 2 and R gears.

if the engine is not running however, there is no hydraulic pressure available for the C5 solenoid to effect its clutch…

 

[Keith Knight]

Aren’t they in neutral when everything is off? Mine will roll if I’m parked on a slop and I disengage the parking brake. Meaning it’s in neutral. I didn’t think they had a transmission park position like standard vehicle.

 

[chucky]

Aren’t they in neutral when everything is off? Mine will roll if I’m parked on a slop and I disengage the parking brake. Meaning it’s in neutral. I didn’t think they had a transmission park position like standard vehicle.

@Third From Texas was telling me a while back that there was something on the a1r trucks about something holding them but i cant remember the details

 

[GeneralDisorder]

You must cage the brakes if you don't want to hookup air.

And remove the front and rear driveshafts. You don't want the wheels turning the transmission without fluid pressure to provide lubrication. Technically you can do it for short distances under a specified MPH but I wouldn't risk it. Who knows how long it's been since it was driven and how dry all the components inside the transmission are.

That's how the military does it. They don't screw the with axle shafts. Cage brakes, remove driveshafts, tow vehicle.

 

[Guyfang]

What TM are you quoting? TM 9-2320-392-10-1?

 

[GeneralDisorder]

@Third From Texas was telling me a while back that there was something on the a1r trucks about something holding them but i cant remember the details

Nope. I have the same truck as he does and mine will gladly roll away on you if you air up the front glad hand.

 

[GeneralDisorder]

What TM are you quoting? TM 9-2320-392-10-1?

TM 9-2320-365-10 (M1078 manual - M1083 will be the same in this regard):

 

[Ronmar]

The Allison 3000 series does not employ any locking/park pawl in its design. It will roll any time that the engine is not running(no hydraulic pressure to lock clutches) and a gear is not selected…

The lube level is below the turbine assembly, so no possibility of natural splash in the main trans housing. When towing, the transfer is flooded, so all that is lubed ok, and the only thing spinning in the upper is the output shaft into the last planetary carrier In the main transmission. That is what will run dry, hence the speed and distance restriction for a coupled-in flat tow. If you don’t know for sure when this thing was last driven normally, probably best to drop the shafts and cage as needed if it won’t accept towing air from your running vehicle…

 

[MarkM]

You must cage the brakes if you don't want to hookup air.

And remove the front and rear driveshafts. You don't want the wheels turning the transmission without fluid pressure to provide lubrication. Technically you can do it for short distances under a specified MPH but I wouldn't risk it. Who knows how long it's been since it was driven and how dry all the components inside the transmission are.

That's how the military does it. They don't screw the with axle shafts. Cage brakes, remove driveshafts, tow vehicle.

I concur

Mark

 

[Guyfang]

This is the procedure straight out of the operators TM for your truck.

 

[JRKJeeper]

Neutral engages the C5 clutch in the transmission. I have not specifically determined what the C5 clutch does for you in neutral… now I do know that Allison does not like to switch more than one solenoid pair at a time. IE: using pulse width modulation, they roll off one, while simultaneously rolling on another to help maintain stable pressure During a shift. C5 is in the mid transmission group, and it is used in both D and R. Putting it on in Neutral would be an obvious step to prepare to shift into D or R and you would only be engaging one other solenoid valve to shift into 2 or R… with the exception of shifting down into first, all of the other shifts only effect one of the 2 solenoids currently engaged to shift from one gear to another. C5 is only used in the 2 and R gears.

if the engine is not running however, there is no hydraulic pressure available for the C5 solenoid to effect its clutch…

Thank you. I was ruling out the possibility of damage if someone drove it to its resting spot in gear and just shut if off. So I appreciate that

 

[Third From Texas]

Nope. I have the same truck as he does and mine will gladly roll away on you if you air up the front glad hand.

He's talking about the trans.

For those that don't know, the A1R trucks have an odd sort of "park" feature in that model Alison. My truck sits on an inclined driveway (typically backed in). With the ignition on or the truck running, I can put it in neutral and release the brakes and the truck will just sit there on an incline as if in "park". I do NOT count on this feature to secure the truck, but I can release the air brakes and the truck will not roll as long as it's running (or the ignition is on).

I damned near killed myself one time as a result of this "feature". I was moving the truck over to make room in the driveway (I was parked facing down hill). I backed it up hill and set the brakes. I got out to check and it wasn't over far enough, so I moved it again and set the brakes. It required several attempts before it was in the right spot. Satisficed with where it sat, I reached up from the ground and shut the ignition off. Yeah, well it turned out that I had inadvertently not set the parking brake that last time. As soon as I flipped the ignition off, the truck started rolling down hill (with me standing in front of the front tire). Fortunately, I was able to grab the steering wheel and yank myself up and into the cab. I stopped the truck, but not before it had rolled out 20 feet into the street.

So yes, the A1R trucks have a sort of "park" feature in the transmission. And it disengages when the ignition power is shut off or the truck is put into gear. But it will actually hold the truck in place on an incline.

 

[Keith Knight]

So according to the manual as long as you drive less than 100 miles and stay under 35 mph, just cage the brakes and pull it. Personally I couldn’t imagine pulling it any faster than 10 mph.

 

[aw113sgte]

He's talking about the trans.

For those that don't know, the A1R trucks have an odd sort of "park" feature in that model Alison. My truck sits on an inclined driveway (typically backed in). With the ignition on or the truck running, I can put it in neutral and release the brakes and the truck will just sit there on an incline as if in "park". I do NOT count on this feature to secure the truck, but I can release the air brakes and the truck will not roll as long as it's running (or the ignition is on).

I damned near killed myself one time as a result of this "feature". I was moving the truck over to make room in the driveway (I was parked facing down hill). I backed it up hill and set the brakes. I got out to check and it wasn't over far enough, so I moved it again and set the brakes. It required several attempts before it was in the right spot. Satisficed with where it sat, I reached up from the ground and shut the ignition off. Yeah, well it turned out that I had inadvertently not set the parking brake that last time. As soon as I flipped the ignition off, the truck started rolling down hill (with me standing in front of the front tire). Fortunately, I was able to grab the steering wheel and yank myself up and into the cab. I stopped the truck, but not before it had rolled out 20 feet into the street.

So yes, the A1R trucks have a sort of "park" feature in the transmission. And it disengages when the ignition power is shut off or the truck is put into gear. But it will actually hold the truck in place on an incline.

That doesn't jive with my experience, same situation mine will roll down my driveway in neutral and engine running. I do have some drag but I think it's from a sticky brake.

 

[Third From Texas]

That doesn't jive with my experience, same situation mine will roll down my driveway in neutral and engine running. I do have some drag but I think it's from a sticky brake.

I just assumed it was a thing with the upgraded trans.

I'll take a video after the holidays.

 

[Ronmar]

So according to the manual as long as you drive less than 100 miles and stay under 35 mph, just cage the brakes and pull it. Personally I couldn’t imagine pulling it any faster than 10 mph.

As long as it was driven normally to the point where you are starting the tow from then everything inside the trans would have been normally lubricated, and you should be OK for up to a 100 mile flat tow at low speed.

 

[98G]

I've done *this* for a couple of miles. I'd think you could get away with essentially anything for a few blocks.

 

[GeneralDisorder]

I just assumed it was a thing with the upgraded trans.

I'll take a video after the holidays.

I confirmed this morning that my truck does NOT do this. Engine running in neutral - truck rolls easily down my slightly sloped driveway when the parking brake is disengaged. I have ZERO drag. My driveway is only very mildly sloped.