wheeler73

Both. The vecu monitors the exhaust temp and can shut the engine down or derate it if the exhaust temp is to high. The vecu controls the gauge.

They are a good solid truck. I would like to see the maintenance records and have a good shop or dealer look the truck over. As we know it is a used truck and can't guarantee it will not have any unseen issues.

We have to send ours out to be tested. As far as I know most dealers are like ours and send them out. Some of our customers just have us put in reman injectors and not bother with having them tested. What issues are you having?

The MP engines also use the engine brake combined with the turbo closing off for engine braking.

The only non triple counter shaft trans in Mack production is the M drive.

The system is actually not that bad. Do not clean any DPF or SCR catalyst or filter with water. The most common issue with these are NoX sensors. I change them out all the time. I have only seen a couple of bad DEF pumps.

You will also need a ABS module for trailer brakes installed. Unfortunately there is no cut and dry air schematics for installing the trailer brakes. Have the Mack dealer print out one for the same year and model with trailer brakes.

There is an updated delts seal kit for the unit pumps. Also the bolts must be tightned down evenly or the o-rings will get cut or nicked. Make sure the bores are clean and smooth. Always use new unit pump bolts with a little oil on the threads and torque to 60 ft lbs. Also make sure it is not leaking between the solenoid and the body of the unit pump. If it is there is a seal kit for that but it takes a special torks plus bit to remove the screws.

Which trans is it and what is the issue you are having?

The exhaust leak will not be your issue. The only issue the exhaust leak at the outlet pipe will have is low exhaust temp. It will not cause data link codes.

I have seen quite a few alternators cause this. Check all battery, ground and power connections. Make sure you check the frame ground inside the left frame rail by the engine and the power and ground connections on both sides of the cab pass through by the steering column. I have seen a lot of the above loose and causing voltage fluctuations.

Yes unfortunately you have to remove the turbo and egr cooler. Just be carefull removing the turbo as the bolts do like to sieze up. Rember to use nickel anti-sieze on any exhaust component bolts and nuts.

I agree with farmer52. What are you looking to use the truck for?

No problem just keep us updated.

They are pretty solid. Do not see a lot of issues with them. We just have our regular customers cleaned at around every 4500 hours. What kind does the truck you are looking at have. One on the back of the cab or one behind the passenger steps? The most common issue is the 7th injector. See if it has the air purge kit installed. It will have 2 lines into a tee on the 7th injector. If it does not have an air purge kit on it you will want to have one installed. It helps with the 7th injector issues.

The DEF systems are on US10 emission trucks. There are some 2010 and 2011 trucks without DEF but very few. The biggest issue with US10 emission trucks that I have seen are the NoX sensors. The 09 CHU should be a DPF only truck unless it is a very early US10.

Sounds like you may have burnt injector cups. Could also be other issues but that is the most common. Take to the dealer as they can test for air in the fuel to see if you have possible burnt cups.

Not that I have seen. Stranger things have happened. Has the dpf been cleaned? They are supposed to be cleaned every 4500 hours.

Those are a common issue. How many hours are on the truck?

The trans is a reliable trans if they are maintained properly. Sounds like a possible synchronizer.

What are your temps in the dpf and it sounds like you have a non catalyst dpf. I have seen the atomization modules go bad too. If it is a catalyst dpf the hydrocarbon dosing shut off modules go bad too. There are a lot of things it could be but those are the most common along with temp sensors.

The correct way is to use a flow/pressure tool for the power steering. What is is doing? Does it make any noise when turning the steering wheel and has anything been done recently?

Glad you found it. Always check the easy stuff first.

Check all your grounds and powers. I have found many loose cab pass throughs and ground to the left frame rail by the engine cause lots of issues. Also check the main cab bulkhead connector and the wiring running down from it as I have seen broken wires in the chassis harness where it runs down by the treadle valve.

Also have the calibration codes programmed.