Mackpro

We finally cut up one of the expansion tanks that the low coolant sensor pushes into . The sensor pushes up into a pocket with coolant around it but the pocket is sealed and no coolant actually touches the sensor. There is a floating plastic ring with a metal washer inside it that floats up and down over the pocket that holds the sensor.  To test we pulled the sensor out of the expansion tank but still plugged in to the harness. With key on , the low coolant alarm went off. We slid  a metal washer over the top of the sensor and the low coolant alarm went off as long as the washer was near the top of the sensor. Slide the washer to the bottom and the alarm cones on. 

Front drive axle hubs 11QJ4222 (25131406) and the rear drive axle hubs are 11QJ4222P2 (25131407). Old and updated parts numbers shown . Only difference is one has the tone wheel for the ABS sensor to read. No stock at any of the Mack parts warehouses . 

With out a VIN it’s impossible to guess. To many axle combination possibilities. A local guy here ordered 7 CTP’s with the spoked Dayton style hubs front and rear to match his older trucks. 

The bell housing is pretty much sealed from engine  oil so it point to the rear main seal. They update the rear main seal a few years back . The new one goes in what looks like backwards best I remember. We put a couple in and they leaked worse. We found out that we put them in backwards. Check your transmission fluid If you have a Mack manual transmission, the oil pump for the trans cooling is inside the transmission bell housing . We have replaced the piping and hoses and o-rings inside the bell housing multiple times on our manual trans trucks due to leaking into the clutch area. There was updated parts fir this as well. In one extreme case I saw a bull gear go down and eat through the rear engine timing cover/bell housing. 

The older ones had the part numbers right on them . 17QF***P*** would usually be the number. The numbers after the P were  the important ones. This was the variation or length number. 

On 9/23/2022 at 10:05 AM, fjh said:

I doubt Mack will not let you have the Xt program not enough cooling will be the excuse or a non Mack drive line will be another excuse!

The good thing about VMAC 3  ECM Programing ( ETECH, CCRS and ASET) is there are ways around asking corporate for permission for HP upgrades. With dealer access you can program as many ETECH engine ECM’s as you want with the XT file. Now finding a dealership that knows how to do it and that will do it is the problem. 

Most all ETECH’s will only turn 1950 in the last/top gear. However 2100  or 2150 ( I can’t remember) in all the lower gears is normal. I think the ASET AI with AMI engine data files  ( AMI 370 for example) would go higher in the last gear. There might have been a few other specialty data files that would go higher as well. 

There is a dimmer switch for the dash lights. I have replaced a few that were bad. Not sure if there is a fuse just for the dimmer it’s self . 

As Vmac3 mentioned, there are very specific sealing procedures when putting a head back on a MP engine.  On the upper rear timing gear cover. The early ones were aluminum and were good. Just change the rubber gasket and all is good. The newer covers are plastic and junk. I replaced the whole cover every time because they warp and leak. Also using the hood down tool that pushes the cover down while you tight the screws is a must 

46 minutes ago, Joey Mack said:

MP, do think the starter button will cause any issues.  I know the '09 that I did, worked fine..  

it’s worth a shot. 

This is really a hard one as all the start relays go back to the trans ECM that is no longer there . Somewhere there is a Relay #20 ( Mack doesn’t say where) start enable relay. It doesn’t show up on any of my fuse box diagrams. There is also a relay usually mounted on the outside firewall labeled MEIIR, I was hoping jumping this relay would work but it won’t as it goes back Trans ECM.  The trans ecm powers up 2 relays sorta in line , the hidden relay 20  and the regular start relay #36 that in the fuse box by the clutch pedal. The main goal is to get 12 volts on wire CB28A  at the VECU connector B pin 28. You also have to put 12volts on the CB28B wire at relay 20 which will feed back and engage the regular start relay 36 . Be very careful with relay 36 it can be turned and inserted 90 and it will never start . 

I’ll see in the wiring diagrams for a 2012 Auto shift if it’s a simple jumper harness added in like the older CXN and CHN’s 

The engine ecm controls the ground for that small solinoid on the starter. The engine ecm looks for the start signal from the VECU, which is looking for a neutral signal from the  now missing trans ecu . The VECU can be reflashed from the dealership to a manual trans. Years ago Mack would not this on the 2008 and up trucks but a couple  years ago they said they would. Removing the Auto shifts and Ultra Shifts in the older grey engine trucks was easy to by pass all the wiring . Not so sure on these MP equipped trucks 

There was a software update for the EGR cooler efficiency code  some years back . You can remove the hose and elbow on the front of the cooler and blow it out with blow gun .  Wear a mask because black soot will fly everywhere. Then replace the EGR temp sensor and clear code . I’ve had decent luck doing that when  replacing the EGr Cooler wasn’t option due to parts availability 

Mack really does not recommend this but you can have the axle bent to get the camber right . A local heavy duty alignment shop here does it. 

As in exhaust flow abs pressure through cooler ? 

Your engine software is a Step 5 and Vehicle software is step 12b so your in good shape there . That’s the newest you can get . 

11 hours ago, Jlam said:

No codes, it did this before I blocked the egr. Thought blocking it would help but then found this on my boost issue from a stop. Lmk what you guys think I can do 

What’s the model and last 6 of Vin and I can have my guy see what software levels are in it 

If you got that high of exhaust temps then possible boost pressure leak. While the AI engine is fairly reliable, 4.3 MPG was the usual average of all my buddies CV713’s . I always drove them with throttle pedal to the floor, loaded or unloaded. Does it have a turbo boost/manifold pressure guage in the upper left corner of the dash?

Unusual code . Check the 3 connectors on the back of the dash cluster for pins pushed out .  Has the cluster been replaced? This code is commonly seen inactive after doing software update on the cluster. Cluster possibly out of another truck/wrong part number. Unhook any Qualcomm or data loggers that are on any of the data lines. 

1 hour ago, Vmac3 said:

Nox sensors have been an ongoing issue with the vehicles. I have found that if one has failed the other will surely follow. Just wondering, do the one box systems plug up with dried DEF still like the older 2 piece style?

V

The very first one box systems had a few issues but they changed the DEF doser gasket/insulator and that seemed to solve the issue.  Had a few DPF filters crack in the early ones too. Our oldest one box system truck is a 2017 with 400,000 miles and just replaced both NOX sensors this week for fault codes. However now it has codes for pumping injectors/ camshaft lob slip. Which might be the cause of the NOX codes. All one box system trucks are common rail engines 

That’s awesome!  We always try to do a 45 minute test drive at highway speeds on SCR issues. After 45 minutes, plug back up and check codes . Just because lights are not on the dash doesn’t always mean there are no codes pending 

I believe the PPID 270 is inlet nox sensor code. The PSID 46 I’m not sure on .What’s model and last 6 of vin 

The minimum efficiency is 80% , it logs the last 5 efficiencies test . If the last 5 are below 80% then it’s a ongoing problem 

You getting the dreaded P20EE code?