Overload symptoms

[Sregorb]

Let me start with: No, I have not towed overloaded nor do I intend to.



But out of curiousity more than anything, when you take one of our trucks and load it down progressively, what are the symptom(s).



My limited experience tells me that as you increase load in a linear fashion the following happen:

1. EGT's will climb linearly as well until it gets to a melting piston temp. Now hopefully the melting piston temp is significantly above the max tow rating for the vehicle.

2. The boost increases until maxed by limiter, or if bypassed shredding the turbo blades.

3. The truck would settle further down on the rear bump stops and flatten the leaves of the springs until a mount breaks.

4. Transmission slippage increases more and more until torque convertor no longer engages.



If I'm on the right track, and those are right, what else?



Another curiosity question comes up, can a driver tell if his/her overall weight combined with speed is too much? Other than the obvious "go weigh it" answer that is... Is it as simple as watching EGT's and keeping it below, say 1200 degrees pre turbo? How about post turbo, etc?



Brian

Inquiring mind thirsty for knowledge.

 

[Eric_77]

1. temps are aslo dependent on outside temps and how fast you are moving so I would not base load on EGT.



2. don't know



3. had truck sitting on the stops I think axle would break before shackle broke as the shackle is not taking any more weight once on the stops.



4. transmission slippage and engagement are so varied and time detreiotes a transmission with a heavy load so a load of 30k may not slip the transmission at new but then a 15k load may slip the transmission at 100k miles from repeated overloading.

 

[SRadke]

1. EGT's will climb linearly as well until it gets to a melting piston temp. Now hopefully the melting piston temp is significantly above the max tow rating for the vehicle.

2. The boost increases until maxed by limiter, or if bypassed shredding the turbo blades.

3. The truck would settle further down on the rear bump stops and flatten the leaves of the springs until a mount breaks.

4. Transmission slippage increases more and more until torque convertor no longer engages.

Are you serious?



1. ) EGT's do climb with load but not exactly linear and will not get to piston melting temps on a stcok truck. The stock design and program doesn't let them have that much fuel.

2. ) Boost does increased and is somewhat limited by the wastegate but moreso by the amout of fuel. Keep in mind a turbo is dynamic and it take fuel to spool. There are limiters in the program but a stock truck should never touch them.

3. ) With too much load it will settle to the bumpstops. Mine has been there. Beyond that you sould start worrying about your differential and tires.

4. ) A stock engine will not slip a stock transmission or clutch if it's in good shape. They are designed to work together.



The problems you're looking for when loaded overly heavy will come from the law. You're truck will hate you for it and prematurely wear but not like you've described above.







-Scott

 

[klenger]

Define "overloaded". That can mean anything from 1 lb over the GVWR to 3000 lbs over GVWR. You can overload the GVWR and still be significantly under the GCWR, which is the load the engine sees.

 

[AfterBurner]

you will overload your truck LONG before you overload the cummins to the point that you're talking about. you're truck will settle and become extremely hard to steer and handle. almost feels like the front tires are only touching the ground intermittently. if you pick up much speed it can get real scary! If you're overloaded and doing highway miles, your tires will get HOT and you will have a high likely hood of a blowout (more so, for those running 285+ D-load range tires). a transmission/ clutch assembly in good shape, that is built to the engines power will not slip. You might have to slip the clutch to get going though.

An overloaded truck can make for a really long trip.

 

[Sregorb]

This is just an exercise in theory to answer a few curiosity questions, kinda a "what if" brainstorm.



Scott may have just answered one for me which is whether or not you can seriously "damage" a stock truck with a load (up to GCWR) by trying to push it too hard. It sounds like the answer is no, it has safeguards in place to prevent damage beyond the increased wear to be expected with ANY load.



Modify the truck though... all bets are off (more fuel=hotter temps=more damage)



So now we covered up to GCWR but what if the load keeps increasing (like sled pulls I suppose) does it keep going until the acceleration can no longer overcome the load and then reverse (ie. the load decelerates the truck until it stops)? Kind of like if you try to pull too much of a stump from the ground and the truck makes noise but goes nowhere?



I thought of another item to: the stress of the drive shaft has to be huge if power is applied and the load is reducing speed... .



Brian

 

[SRadke]

Here again, you probably won't get into trouble with a stock truck. I would imagine a 3k holeshot in first gear 4-low on asphalt would break something but what did you expect? The drivetrain components are designed to take the power of a stock truck, you'll run out of power before it becomes a problem. What gets people in trouble being overloaded is usually trying to get all the weight stopped, especially going downhill.



-Scott

 

[Sregorb]

Excellent info Afterburner. That raises another question though. How would a person measure tire temp (beyond touching and saying, "ow that's hot" )

Would there be a cost/benefit justifying getting some sort of a "monitoring system?"



Klenger-Overload in this case would be defined as increased to the point of where the truck is incapable of moving it.

Kind of like hooking a pintle to a cable that's wrapped around a mountain... :-laf

the GVWR will be empty truck plus weight of pintle and 1/2 of cable I suppose but GCWR would be astronomical.



Brian

 

[klenger]

What size mountain? I have a Cummins, don't you know?

 

[JRMora]

Excellent info Afterburner. That raises another question though. How would a person measure tire temp (beyond touching and saying, "ow that's hot" )





Brian

By using an optical pyrometer. I use one in my business for looking at bearing temps on machines. You can get a lesser priced one at any Grainger or McMaster Carr or measurement supply house (Omega?). Probably several on this forum use them. I am planning on buying one for myself when I get a trailer to have handy for measuring my trailer tire temps. Good way to avoid a blow-out!



Juan

 

[Sarge]

Brian, your answer is fairly simple. Overloaded is not determined by how much you can move, it is determined by how much you can STOP. These motors are crazy tough, and it would be hard to load so much that the truck wouldn't move. Brakes my son are what turns a routine trip to the dump, or a short RV trip into the nightmare you wish you never had. I've driven and loaded about every make and size of non-commercial truck produced. They all will get going one way or another. Now stopping them is a different story... ..... Bottom line, use your head and be safe. Hey, it might be me on the road in front of you... . Sarge

 

[jnelson]

When your trailer starts to "bow" in the middle.

Your reciever hitch hits the strret when you pull out of the driveway.

You have to get up to 2000 rpm in your auto transmission to get the load moving.

You blow all your wheel seals.

Your brakes dont work cause their oil soaked.



Now your overloaded.



That was 12 pallets of ceramic floor (36,000 lbs) tile on my 36ft gn. Never again.

 

[GaryCarter]

When your trailer starts to "bow" in the middle.

Your reciever hitch hits the strret when you pull out of the driveway.

You have to get up to 2000 rpm in your auto transmission to get the load moving.

You blow all your wheel seals.

Your brakes dont work cause their oil soaked.



Now your overloaded.



That was 12 pallets of ceramic floor (36,000 lbs) tile on my 36ft gn. Never again.

You are talking about the 1500 here, right? :-laf

Mike

 

[LesStallings]

Radio Shack has a cheap IR thermometer. I check my tires at every fuel stop when towing.



When my truck was stock, it WAS possible to exceed EGT recommendations under load in 5th gear. My belief is that it is possible to hurt a stock truck.

 

[snapshot]

Tire temps

They do make a gadget that will monitor your tire temps while underway. It consists of tiny sensors with transmitters that are epoxied inside the wheel/tire. They have a motion switch that turns them on when you are moving and then sends the readings to a receiver on your dash every few seconds. The batteries will long outlast your tires so that is not a problem. When a tire starts to heat up you know it right now. The unit is a little spendy but then what price safety? I expect the best application would be on a heavy RV trailer.

 

[amillstream]

When you bend axles and snap trailer leaf springs, your overloaded. Not that I'd know anything about that.