KKRT Posted June 16, 2023 Author Share Posted June 16, 2023 Thanks Mackpro. Great info. My truck is an MP8. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 16, 2023 Author Share Posted June 16, 2023 Thanks Mackpro. Great info. My truck is an MP8. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 16, 2023 Share Posted June 16, 2023 There are 2 different part numbers for manual trans harness . 21902988 or a 21902987. The possibility the first is for Mack and the second for Eatons . As some newer Eatons have different reverse light switches and speedometer connectors that the Mack and older eatons . Still looking for more info Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 16, 2023 Share Posted June 16, 2023 The biggest issue I see is why it won’t crank with the key. Quote Link to comment Share on other sites More sharing options...
doubleclutchinweasel Posted June 16, 2023 Share Posted June 16, 2023 3 minutes ago, Mackpro said: The biggest issue I see is why it won’t crank with the key. Any circuits that the automatic had to "close" that are being left "open" by having the new box in it? Or was it all in the 'puter? Or could it be as simple as a wire pinched off during the swap? These blasted new-fangled gadgets... 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
Mackpro Posted June 16, 2023 Share Posted June 16, 2023 On the MP8’s. The VECU (vechicle electronic control unit) and the EMS (engine ECM ) both have to agree to start/crank the starter. When you turn the key to start/crank , 12 volts goes to the VECU A connector pin 6. If everything looks good to the VECU it sends 12v out of the VECU connector B pin 28 which goes to the little start relay in the fuse panel by the clutch pedal. This in turns sends 12 volts to the small silver starter solenoid. However the ground wire on this small solenoid goes to the EMS engine ECM bottom connector pin 29. The EMS has final say by internally grounding the solenoid ground wire allowing the solenoid to crank the engine. So everything has to be perfect in the eyes of the VECU and EMS. Make sure the green PTO light is not on . It will not crank if the VECU thinks the PTO is engaged. 2 Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 16, 2023 Author Share Posted June 16, 2023 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. 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 17, 2023 Share Posted June 17, 2023 You Go Boy !! Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 17, 2023 Share Posted June 17, 2023 3 hours ago, KKRT said: 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. That’s weird that your GU with an Allison had the 505 HP program in it . Biggest we could get with an Allison in the GU was 455M like you got now. If you had a Mack manual or M-drive or the higher torque rated Eaton you could get the 505. Engineering told us the radiator in the GU wouldn’t keep the Allison and 505 cool enough. What’s the model number of the Fuller you used? Glad your making progress. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 17, 2023 Author Share Posted June 17, 2023 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. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 18, 2023 Author Share Posted June 18, 2023 Mackpro, see the bottom of the reprogramming sheet. It shows they removed the 505 and added the 455. Reprogram.pdf Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 18, 2023 Author Share Posted June 18, 2023 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). 2 Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 18, 2023 Author Share Posted June 18, 2023 They definitely don't build them like they used to .... Quote Link to comment Share on other sites More sharing options...
doubleclutchinweasel Posted June 19, 2023 Share Posted June 19, 2023 On 6/18/2023 at 10:54 AM, KKRT said: 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). Don't have to convince me of why you took out an automatic and put in a manual. Made perfect sense to me! 1 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
Joey Mack Posted June 19, 2023 Share Posted June 19, 2023 KKRT, I agree with DCW... I would love to see more guys ditch the M-Drive and put a real trans. In the truck.. I know you had an Allison.. I'm proud of you. For what it's worth.. :). Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 19, 2023 Author Share Posted June 19, 2023 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 .... 2 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 20, 2023 Share Posted June 20, 2023 yeah.... i'm a double clutcher myself.. I can float and I do at times, but when I was a full time mechanic, I would double clutch because I didnt know the truck i was driving.. and it worked well with my troubleshooting.. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 20, 2023 Author Share Posted June 20, 2023 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. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 20, 2023 Author Share Posted June 20, 2023 Thanks Jojo. Not trying to start a food fight, but some floaters out there talk about double-clutchers who cant float ... 🙂 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 20, 2023 Share Posted June 20, 2023 he was talking about CV's.. Yours is a Volvo.. What you did will work... Not professional, but............ at this point who cares???? put the truck to work and ... Git-R-Done.. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 20, 2023 Author Share Posted June 20, 2023 Thanks Jojo. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 20, 2023 Share Posted June 20, 2023 All Good... For many many many years I told drivers who would have clutch issue's, you need to use low or 1st, and ask, do you double clutch?? hell No!!! I'm a Real Driver... I don't need the clutch..... Of course when i ask one of them to help me pull the tranny to do a clutch or figure out why the tranny is popping out of gear and such,,,, Cricket's... its all good... There are plenty of drivers who dont use the clutch and they are smooth as silk.. to each his own.. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 20, 2023 Author Share Posted June 20, 2023 10-4 Jojo Quote Link to comment Share on other sites More sharing options...
doubleclutchinweasel Posted June 20, 2023 Share Posted June 20, 2023 13 hours ago, Joey Mack said: All Good... For many many many years I told drivers who would have clutch issue's, you need to use low or 1st, and ask, do you double clutch?? hell No!!! I'm a Real Driver... I don't need the clutch..... Of course when i ask one of them to help me pull the tranny to do a clutch or figure out why the tranny is popping out of gear and such,,,, Cricket's... its all good... There are plenty of drivers who dont use the clutch and they are smooth as silk.. to each his own.. I believe in both...depending n the situation. Let the truck tell you what it wants. 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
KKRT Posted June 21, 2023 Author Share Posted June 21, 2023 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. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.