KKRT Posted June 15, 2023 Share Posted June 15, 2023 Teammates, I just swapped out my Allison with a 13 speed in my 2014 GU713 and I can't start the truck with the key. When I jump the starter, the truck will start and idle and will even drive very slowly. However, the speed gauge shows dashes, engine will not rev past 1400 RPM and truck won't go faster than 14MPH. I took the truck to my local Mack dealer a week ago for reprogramming. They sent an eService to Mack for a new program and instructions. Mack sent them a new program for the ECM and VECU, however truck still won't start with the key and the speedo still shows dashes. Mack instructed them to jump the “Neutral Safety Switch’ with a wire, they called me today and said truck is still not starting with the key. I don't think these guys at my dealership know what they are doing; and of course they keep running up my hourly bill. I NEED HELP. Quote Link to comment Share on other sites More sharing options...
BOBWhite Posted June 15, 2023 Share Posted June 15, 2023 Is the TCM still on the vehicle or did it get removed? How are you hooking up the speed sensor into the 13 speed? I'm not a computer or swapping expert but I've heard about people leaving the transmission control module in the vehicle when they swap in a manual and just tricking the computer into thinking that it still has an automatic. It only revving to 1400 kinda sounds like this might be the case if the computer thinks it's in neutral it may not let the RPM's go over 1400. Best of Luck Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 15, 2023 Author Share Posted June 15, 2023 Thanks Bob. I removed the TCM and the Allison selection pad from the truck. We hooked the 13 spd sensor to the wire that the went to the Allison sensor. Concerning the 1400 top rpm, I will check with the mechanics who helped me with the swap, about the computer potentially thinking truck is in neutral. One main thing is that the speedometer shows dashes, and even after the dealer installed the new program, it still shows dashes. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 15, 2023 Share Posted June 15, 2023 Pull fuse 71 out of the EPDM and see what happens.. that is the Allison fuse.. can you jump the little relay on the starter to turn it over? 1 Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 15, 2023 Author Share Posted June 15, 2023 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. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 15, 2023 Author Share Posted June 15, 2023 Bob and Joey, Mack instructed them to jump the Neutral Safety Switch, but they still couldn't start the truck with the key. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 15, 2023 Author Share Posted June 15, 2023 Joey, fuse 71 removed from EPDM, still no solution. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 15, 2023 Share Posted June 15, 2023 Sorry Bud... Thats all I got... if the engine would run above 1400,on up to gov. speed I would say install starter button until you find the issue.. I had a deleted MP-7 that gave trouble in many ways, and the ignition didnt start the truck. I put a starter button in it and it worked fine. It was a homemade dump truck that a crop farmer had.. his was a manual trans. though.. I wish I could help.. Jojo Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 15, 2023 Author Share Posted June 15, 2023 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. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 15, 2023 Share Posted June 15, 2023 well, at least with the 13 spd. you can get up to about 60+ MPH.. Is it a dump truck or roll off, ?? tractor?? Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 15, 2023 Share Posted June 15, 2023 The 1400 rpm is the default max RPM when there is a “Speed Error” . I always set this to 2150 in the Parameters when setting up a truck. Mack never really explained which speed error. I always assumed it was crank or cam sensor. When the flywheel was changed it’s possible the crank sensor could have been damaged as it reads off the notches on the flywheel. The truck should still start. There is a different wiring harness for manual transmission trucks . Don’t use the Allison harness 1 Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 15, 2023 Author Share Posted June 15, 2023 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? Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 15, 2023 Author Share Posted June 15, 2023 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. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 15, 2023 Author Share Posted June 15, 2023 Highway work with rolling hills, 300 - 350 miles a day Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 16, 2023 Share Posted June 16, 2023 (edited) 4 hours ago, KKRT said: 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? It’s a separate harness that plugs into the chassis harness on top of driver side frame rail. I’ll see if I can get some pics in the morning. I’m thinking the Allison harness is separate and goes directly through the firewall with it’s own harness. Edited June 16, 2023 by Mackpro Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 16, 2023 Share Posted June 16, 2023 As far as Corporate helping dealers with issues like this ( change overs as they call them) it’s non-existing. They will set up the data files and if you lucky they will give the dealerships a Vin of a very similar truck as yours but with a manual transmission. Then it’s up to the dealership to go through each page of the parts look up and compare what’s different, from fuses, breakers , relays and harnesses. Been through similar situations with them years ago. They don’t make a parts list or how-to on things like this. Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 16, 2023 Author Share Posted June 16, 2023 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. Quote Link to comment Share on other sites More sharing options...
fjh Posted June 16, 2023 Share Posted June 16, 2023 So i am confused you took out an auto and are replacing with an auto? or took out a standard ? Just mentioning a clutch switch jumper if the standard was removed! Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 16, 2023 Share Posted June 16, 2023 Auto to stick... Quote Link to comment Share on other sites More sharing options...
KKRT Posted June 16, 2023 Author Share Posted June 16, 2023 I took out an auto and replaced it with a 13 spd manual. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 16, 2023 Share Posted June 16, 2023 First make sure 20 amp fuse/breaker is installed at fuse 42 in fuse box by clutch pedal. More info to come Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 16, 2023 Share Posted June 16, 2023 There is a 12 wire connector/harness that plugs into the chassis harness under cab . This is the manual transmission harness. It’s for the speedo sensor, reverse light switch , transmission temp sensor and PTO. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 16, 2023 Share Posted June 16, 2023 Looking to get you a part number here shortly Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 16, 2023 Share Posted June 16, 2023 Also is this a MP7 or MP8? Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 16, 2023 Share Posted June 16, 2023 Also make sure the start relay is installed correctly. If turned 90 degrees it won’t start. People pull theM out to check them and put them in wrong. More info to come Quote Link to comment Share on other sites More sharing options...
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