KKRT

After swapping the Allison in my truck for a manual and reprogramming the truck, speedo blanks out (dashes) and speed dial stops working between 25-30 MPH. I was told that the wiring from speed sensor to ECM is different because the Allison has a TCM. I have been told to compare wiring diagrams and do some rewiring from speed sensor to ECM. Does anyone know this for sure, and can someone provide both wiring diagrams? 

Yes Jojo. Everything is working now. I'll update when I start pulling some hills next week.

I'll later summarize my process for folks who may be interested. Since the gray engines went away in 2007 with start of the CTP,  there are hundreds of red engines out there (MP7 and MP8). We all have to be creative with our red engines, if we want to do some different things (just one guy's opinion,  Jojo).

As mentioned, I started the truck yesterday with the key buy running a straight wire from the ignition ground wire directly to the starter solenoid, after trying unsuccessfully to react the starter relay buried somewhere inside the dash.

10-4 Jojo 

Thanks Jojo.

Thanks Jojo. Not trying to start a food fight, but some floaters out there talk about double-clutchers who cant float ... 🙂

Fathers Day weekend and laying under trucks don't go very well together; the family won that weekend battle by a landslide so, I didn't get to work on starting trying to start my truck over the weekend.

However, with the help of a friend who likes playing around with wires, I was able to start the truck with the key today. I'll post some pictures tomorrow. We bypassed the ignition switch ground straight to the starter solenoid and the truck started.

Mackpro and others may confirm this, but my buddy explained that Mack puts a relay inside the dashboard on GUs (on the firewall on older Macks). We took almost the entire dashboard and panels apart, but could not get to the relay which sits somewhere below the fuse box in the middle of the dashboard. So we ran a wire straight from the ignition switch ground wire to the starter solenoid. Hope this does not cause any problems however, please chime in. 

Thanks, DCV/Jojo, and others out there who share the same feeling. I was getting a bit worried over the Father's Day weekend when I was not getting any love from the crew on my project.  🙂

Torque converters, electric and electronic shifters are all great technology however, some of us like DCV's (his name says it all), can't give up double-clutching and floating ....

They definitely don't build them like they used to ....

We all love Macks, so I know many people following this may be wondering, “Why did this guy do this project?”. We know there is one camp that will always say, “…sell the Allison and buy a GU with a stick/manual”. Main reason I did it because it’s my personal truck I drive daily, my 2 drivers drive my other trucks; after 4 years of city work, I now do highway work, I feel manual works better on highway with hills (personal opinion only); plus, I wanted to see how easily this could be done.

Concerning replacing the Allison with another personal truck; my 2 options were $200K for a new one or buy another used one. I don’t have new truck money, so it would have been another used GU. However, after cleaning up all the ‘bugs’ on my truck in the last 4 years, I didn’t want to repeat the process with another used truck (engine harness, 6 pack injectors, VGT, radiator, coolant reservoir, water pump, fan clutch, power steering/fuel pump, TCM reprogramming, DEF issues, etc etc).  

Mackpro, see the bottom of the reprogramming sheet. It shows they removed the 505 and added the 455. 

Reprogram.pdf

Mackpro, I thought it was the other way around myself, that the Allison had the 455 program and the manual and MDrive had 505. However, the printout the tech gave me from the EService and the programming stated they removed the 505 and installed the 455. Not sure why, I asked the tech and he said he could not explain that.

Concerning the transmission, I checked with the dealer before I started the project, and EService they received from corporate said the could only support the Eaton FRO transmission. I had initially wanted to put in an Eaton RTLO (18 spd) transmission, but Mack said no. Maybe, that could only be specific to that year GU. I don't know, but I learn something new on this everyday.

Mackpro, thanks for your efforts and great info. Truck still will not start with the key, but I am happy to inform the team that I achieved a partial victory today; this concerns the manual transmission harness. I made sure to discuss every info you provided with the senior tech assigned to my truck today (fuse 42, solenoid, transmission harness, etc.).  He installed and second transmission harness (PN 21902987) and the truck now shows the speed on the dashboard, the engine revs past 2000 rpm, backup lights and buzzer works, so does the PTO. 

So, with the speedo working and the engine not stuck at 1400, I jumped the starter and took the truck from the dealer to my yard this afternoon (mainly to avoid the ringing cash register). I told them I'll try to figure out the starting situation myself; we'll use the info you provided in the last message, or install a starter button for now.

Something interesting I discovered; the new program corporate sent to reprogram my truck for the Eaton 13spd is 'Mack 455HP Maxidyne'. My original program I had with the Allison was 'Mack 505HP MaxiCruise'. Not sure why I lost 50HP in that deal (to be a little humorous, not sure why anyone will pay money to lose horsepower); I may not see a power loss with the Eaton 13spd when loaded at 70,000. I'll keep you posted.

Doubleclutchinweasel, your guesses are as good as mine (pinched wire, computer, open, open circuit); we'll search this weekend. 

Thanks Mackpro. Great info.

My truck is an MP8.

Thanks Mackpro. Great info.

My truck is an MP8.

I took out an auto and replaced it with a 13 spd manual.

Thanks, Mackpro. This info is very helpful, it gives me a baseline for discussion when I talk to the techs today. I thought my local dealership guys knew their way around their machinery since that's all they do; and not to mention their healthy hourly rates. I thought the physical swap which I did in my yard was going to be the hardest part; well?

I'll appreciate any pictures you can send so that I can show it to them.

Highway work with rolling hills, 300 - 350 miles a day 

Joey, 2014 Dump truck. The Allison with 4.50 rears will do 80 mph. Doing dump truck work in DC (Washington) with the Allison was great. However, now I do 300+ miles on the highway with some rollong hills every day, so the 13 spd is better.

Thanks Mackpro. I appreciate the info. We'll check the crank sensor tomorrow.

Concerning wiring harness, are you talking about changing the main engine harness, or are you talking about a transmission harness?

Thanks Joey. Good advice; if I can somehow figure out the issue with the engine not revving past 1400, I'll install the remote starter button.

Does anybody know if the limited speed (the 1400 rpm) is controlled thru the ECM or VECU (I can try to get the ECM or VECU privately reprogrammed)? Any feedback will help.

Joey, fuse 71 removed from EPDM, still no solution.

Bob and Joey, Mack instructed them to jump the Neutral Safety Switch, but they still couldn't start the truck with the key. 

Yes, I can jump the relay on the starter to start the truck. As mentioned in the first post, I can actually start the truck when I jump the relay on the starter. Truck will start, idle and drive slowly (1400 rpm, 14 mph). Truck is currently at the dealer, and they are not sure what to do next; I'll speak to the tech about fuse 71 to see what happens.