Help! Truck acting up!

[t444ebusser]

Hey guys, I was driving my 1998 T444E yesterday on my trash route and need some help diagnosing some issues. Occaisionally over the past few months - as in like once or twice per 100 stops - when i would go to set the parking brake to service a can, the truck would start lugging. On two instances the truck died. It did start right back up no problem. Yesterday, when I would pull up to a stop to service a can, about a second or two after setting the hand brake, the engine would lug- it would skip sort of and drop lower in tone. It never died but made my heart drop just about every time. This may be a seperate or related issue, but halfway through the route, after servicing a can, i shifted into drive and released the handbrake and the truck would not go into gear. i coasted down a slight hill and pulled off the road. i shut the truck off and started it back up and it went into drive fine. finished out the day driving another 100 miles and never had a shift issue. The batteries are pretty old and I had been trickle charging them every night with a warming pad under them - have three stuffed into the battery box. Any idea what might be going on or how to diagnose? I was thinking maybe the bad batteries, voltage regulator and a trans fluid change but would like to diag instead of throwing parts at it- though all three of these are very likely overdue. thanks in advance!

 

[t444ebusser]

the truck lugging at stops would happen if i left it in drive or if i put in neutral - but only happened when i set parking brake. never on a single occurrence has this issue occurred at a red light or other stop having not set hand brake for example.

 

[t444ebusser]

spoke with a repair shop. they suggested starting with batteries. we were unable to explain how bad batteries could make the engine lug - but only when park brake hand lever was engaged. he did let me know that engaging the parking brake while on a hill in drive - something i do as added precaution - places wear on torque converter. i'm thinking the clutch material clogged a shift solenoid yesterday in the event when it did not want to go into drive.

 

[ewo1]

Your not giving enough information for anyone to fully understand what is going on. you talk about the symptoms and that about it....

so you don't have a bus, you got a garbage truck?

What size is the truck, make and model ?

you only mention that you own a T444E.

I guess you assuming your problem can only be an engine problem ???

well from what I read, your issue only happens when you apply the parking brake ??
Not at a red light or stop sign ???

Not knowing how your garbage truck is built/wired, in this case I have to mention or better yet, ask.... what tranny do you have in your garbage truck.

I am going out on a limb and say you have an Allison ???
Allison TCM 's can be programmed for accessories such as a PTO which in turn would power the hydraulics for your garbage truck.

Think about a bus and a wheel chair lift, how the messaging between the door latch, brake circuit and yes even idle speed are connected.

Perfect example of this might be a fire truck, idle goes up when pumps are turned on...I'm sure the parking brake circuit would also be tied into this "Fire Truck" example I mention...

since this issue only happens when you apply the parking brake I am assuming that the PTO is engaging at the same time ?

for me, the tell tale sign, where to begin looking, is the parking brake circuit and what, if any, other actions are related to apply the parking brake during "stop n go" operations.

If so then I would first look into electrical, maybe a loose wire - connection that when you activate it, it goes bonkers and affects engine idle ???

 

[Mr P]

Wanna know about how a T444E operates? Try Diesel Tech Ron on YouTube. Just call it a "7.3". Fantastic diagnostic info.

 

[ewo1]

To give you a better understanding of what I wrote about earlier, here are 2 pages from the Allison 4th Gen troubleshooting manual which speaks directly to the trans TCM and PTO operation/wiring.

 

[ewo1]

Here is another work page from the manual.
This one depicts automatic neutral when work brake is applied.

 

[ewo1]

And the one that might answer your questions, from the service manual
Automatic Neutral when PARKING BRAKE applied.

You got some studying to do my friend!