Big Truck Not everyone should be allowed to wield tools.

greasytshirt

Moderator
Staff member
Mechanic
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greasytshirt

Moderator
Staff member
Mechanic
This Maxxforce 9 ran like dog doo, and had erratic injection control pressure.

Tomorrow I'm gonna open Pandora's box and look at bearings.
 
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greasytshirt

Moderator
Staff member
Mechanic
Well? We're ready to hear about it. :pokepoke:
The rod bearings had some particles imbedded, but nothing terrible. The crank is ok. Parts have been ordered. I'm going to put rod and main bearings in it, the correct oil pickup tube gasket, get it running, THEN I can finally diagnose the reason why it's here in the first place: the Allison transmission shifts harshly.
 

greasytshirt

Moderator
Staff member
Mechanic
The engine is back together, finally. Someone had been in the bottom end before, and some sketchy things were done.

Inexplicably, one main bolt looked like it was dragged down a sidewalk until a quarter of one section of the threads were flattened. The circumference of the head's flange was also raggedly ground away. No one had ever seen that before. The threads in the block had burrs that needed to be cleaned with a thread chaser. It took a few days to locate one in the right thread pitch and length. It torqued up just fine. The customer was not thrilled when he saw those pics!

The truck fired off fine and with stable injection control pressure it's sounding better than Ive ever heard it run.

Now to figure out the harsh 3-4 shift. Allison 3000 series. I imagine I'll have to drop the valve body assembly and test some solenoids. Yay.
 

ttruck

Expert Expediter
Owner/Operator
good morning,gonna start your day any luck on ac problems that you can help with no power to ac clutch have
replaced everthing except compressor which works fine went over entire hose routing there are no leaks, system has been evaced ,dryer,binary,high pres. switch and all plugs changed ive even changed the evap probe which puts power to clutch and coolant fan, all this has been done yesterday,03-14-16 still no power to clutch this all started uesterday I have pulled all my hair out im just shy of putting a bullit in it any help will be appreciated 2006 m2 freightliner
 

tknight

Veteran Expediter
Tt my m2 gave me nothing but ac issues its entire life till it was put to its death! Sorry still a bitter old fuy
 

greasytshirt

Moderator
Staff member
Mechanic
Customer literally can't believe that an injector and out-of-phase driveshaft (idk if he even knows what that means) were causing his symptoms. Overheard a yelling match on the phone.

Just drive the truck, dummy. Its fixed. Gawd.
 
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FlyingVan

Moderator
Staff member
Owner/Operator
What is an out of phase driveshaft? I haven't heard the term before. And how does an injector cause the transmission to shift harshly?

BTW, I am genuinely interested to learn something new.
 

greasytshirt

Moderator
Staff member
Mechanic
What is an out of phase driveshaft? I haven't heard the term before. And how does an injector cause the transmission to shift harshly?

BTW, I am genuinely interested to learn something new.
This video explains angularity and phasing perfectly. Watch the whole thing.

When you have a phasing issue, a massive amount of vibration develops. This actively damages everything. U-joints, the bearings and bushings inside of transmissions, etc. This leads to excessive movement of shafts, and also to the tone rings attached to them. Rpm signals then get distorted, which makes shift calculations inaccurate.

So we've got a bad misfire, which causes the crankshaft speed to oscillate, altering the engine speed signal and input shaft signal. And we've got huge torsional vibrations altering vehicle speed signal detection, and the TCM is trying to make chicken salad out of chicken s***. When the engine was still cold it wouldn't misfire, and the truck shifted pretty well for a minute or two, then the miss started and so did the banging into 2nd, 3rd, and 4th.
 

FlyingVan

Moderator
Staff member
Owner/Operator
That is a cool video. So, with a driveshaft you have to make sure that 2 things are correct. The transmission shaft and the rear end shaft must be parallel, and the u-joints must be in phase. Learned something new. Thanks.
 
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