The upgrade variants of the M916 NTC400 trucks

[simp5782]

I have a WTEC5 with 1335 miles. It's a beautiful truck. Its been sitting for many years because of the wrong tcm being in it and no power to the controller. I replaced the tcm with on from ALlison and they "said" it was programmed right. It's not. The truck starts, runs, the tcm and controller power up. It will go into all forward gears and shift up and down. It will not go into reverse and when you try it will throw P0122d1 and sometimes P0123d1 error codes. I clear the codes, shut it, off and turn it back on and no codes are active until I switch it into reverse and then it will throw one of the above mentions codes. P0122d1 is low voltage detected at TPS. P0123d1 is high voltage detected at the TPS. The volts to the TPS are correct. It has a new TPS on it. Allison is stumped and lets face it......they charge quite a bit of money just to guess. They have reprogrammed a new TCM and that didnt work either. Ive talked to a couple other owners who tell me the TCM is falsely reading the TPS and causing the problems due to being improperly programmed with a bunch of added "upgrades" that confuse the TCM. CAn anyone give me some assistance in getting my M916A0E1 Wtec5 in reverse? WHo can program the above code into my TCM. Who can clone their TCM for me? Thanks in advance.

@fuzzytoaster

 

[fuzzytoaster]

@fuzzytoaster

Ive been working with him on it. Another SS member has agreed to clone his TCM in a few weeks in hopes to purge this truck's demon.

 

[afc2324]

@fuzzytoaster has been awesome and so is the other person he introduced me to. Im exploring all possibles. I gained some ground today and then lost the same ground. This is such a great truck that Im excited to own and im really looking forward to having it operational.

 

[afc2324]

Has anyone had success with taking their TCM anywhere and getting it reprogrammed with WTEC 5 TCM reprogram code : 4C0010M1007C ? Where did you get it programmed if it did work? Mine throws P0123d1 codes when I try to shift into reverse. I can clear the code but it comes back when I attempt to shift into reverse. My local Allison (Stewart Stevenson) shop is no help but loves to charge by the hour with no solution. It has a new TPS.

 

[afc2324]

Does anyone have a TCM from one of these trucks programmed correctly that they will sell me?

 

[afc2324]

I have a beautiful M916a0e1 but am having trouble locating an A53 Allison transmission control module for it. I have bought two from a TCM place and neither would take the program code and threw hard errors. Does anyone have a tcm for this truck that will work for this they can sell me? Can anyone point me in the right direction to get one? Thank you!

 

[M923A2]

I'm needing some help.
@simp5782

I purchased an Allison 4700SP from Eastern Surplus that they pulled out of an upgraded M916A0. My plan is to upgrade my M915A1 (remove the Allison HT750CRD and replace it with the 4700SP)

Unfortunately, ES lost the TCU and did not pull the throttle position sensor with the trans and torched some wires/cooling hoses in the removal process. This is increasing the challenge of the swap...

Since RRAD installed this trans as an upgrade, the harness is mostly stand alone.

I've hit a few roadblocks and I need some help.

• I have not been able to find any TM's that have the parts list or wiring diagram for the upgrade. Did RRAD publish any TM's for the M916A0? As such, I'm struggling with identifying all the connectors and wires and missing components.
• Next, the TCU got lost... so I need to identify a replacement, but since I’ve been unable to find the TM’s that have the part numbers, I asked EC to send me a pic of another one of their M916's, and it has an Allison A53 TCU. I believe this is a Gen 4, not the Gen 5 you mentioned above that should be in these trucks? Should I be sourcing an A53 Gen 4 or an A59 Gen 5 TCU? What TCU is compatible with the WTEC 5 TCM reprogram code : 4C0010M1007C
• Throttle position sensor. What Part number TPS works with this trans?
• I’ve also attached a pic of the wiring harness and the connectors/wires that I’m not sure what they go to… any help would be greatly appreciated.

Thanks!

 

[fuzzytoaster]

I'm needing some help.
@simp5782

I purchased an Allison 4700SP from Eastern Surplus that they pulled out of an upgraded M916A0. My plan is to upgrade my M915A1 (remove the Allison HT750CRD and replace it with the 4700SP)

Unfortunately, ES lost the TCU and did not pull the throttle position sensor with the trans and torched some wires/cooling hoses in the removal process. This is increasing the challenge of the swap...

Since RRAD installed this trans as an upgrade, the harness is mostly stand alone.

I've hit a few roadblocks and I need some help.

• I have not been able to find any TM's that have the parts list or wiring diagram for the upgrade. Did RRAD publish any TM's for the M916A0? As such, I'm struggling with identifying all the connectors and wires and missing components.
• Next, the TCU got lost... so I need to identify a replacement, but since I’ve been unable to find the TM’s that have the part numbers, I asked EC to send me a pic of another one of their M916's, and it has an Allison A53 TCU. I believe this is a Gen 4, not the Gen 5 you mentioned above that should be in these trucks? Should I be sourcing an A53 Gen 4 or an A59 Gen 5 TCU? What TCU is compatible with the WTEC 5 TCM reprogram code : 4C0010M1007C
• Throttle position sensor. What Part number TPS works with this trans?
• I’ve also attached a pic of the wiring harness and the connectors/wires that I’m not sure what they go to… any help would be greatly appreciated.

Thanks!

I can help answer your questions as Simp and I corroborated on these "M916A0E1" so we call them.

• I have not been able to find any TM's that have the parts list or wiring diagram for the upgrade. Did RRAD publish any TM's for the M916A0? As such, I'm struggling with identifying all the connectors and wires and missing components.
• There are no TM's for this specific truck. The TM's for the older M916 family of truck are still good for all other parts of the truck EXCEPT transmission, front driveline, and minor electrical changes. Fortunately the Allison harness is almost completely independent of the rest of the truck so that simplifies it as you said.

• Next, the TCU got lost... so I need to identify a replacement, but since I’ve been unable to find the TM’s that have the part numbers, I asked EC to send me a pic of another one of their M916's, and it has an Allison A53 TCU. I believe this is a Gen 4, not the Gen 5 you mentioned above that should be in these trucks? Should I be sourcing an A53 Gen 4 or an A59 Gen 5 TCU? What TCU is compatible with the WTEC 5 TCM reprogram code : 4C0010M1007C
• ES owes you the matching TCM for that setup otherwise we are all guessing. Some trucks were WTEC3 but the majority are WTEC4. None are WTEC5 that we know of. I can assure you that buying a newer model TCM will cause you misery and wasted money. I've had several of these trucks and coached 2 other owners though missing or failed TCMs. The end result has been the same; you must have the correct generation TCM and clone an existing TCM to make it work. An Allison dealer will ask for the transmission serial and line you up for it to be programmed and it will be wrong. TCM timing out, no reverse gear, immediate false temp spikes, and no gear selection are the most common symptoms of their attempts.

• Throttle position sensor. What Part number TPS works with this trans?
• I've had success with 29507768. It's listed in the parts TM for the M915A4 as well, they have the BC400 and Allison 4500SP which is the same family as the 4700SP. YMMV.

• I’ve also attached a pic of the wiring harness and the connectors/wires that I’m not sure what they go to… any help would be greatly appreciated.
• You main photo looks correct. Disregard any triangular plugs on the harness near the transmission gear selector that are capped off. That harness is all strung out in the cab of these M916A0E1 trucks with a lot of unused connectors. There is a bulkhead connector in the floorboard of these trucks which is most of your unknown connections/wires in the smaller photo. I can get photos of the truck I have if needed. The install on these trucks was very crude.

 

[M923A2]

Thanks @fuzzytoaster for the info and lessons learned.
I'm not hopeful that ES will find the TCU that went with this trans, I've already been a few rounds with them and I'm not impressed.
As such, it sounds like the TCU configuration will be the biggest challenge.
I'll start doing some homework with Allison's documentation on the 4700SP , A53 TCU, Relay/Power box, TPS, and shift selector wiring, then I'll work on building a wiring schematic for the harness that I have and match it up to Allison's pinouts from their documentation. Hopefully that will help me get ready to tackle the software configuration (by at least knowing what TCU pins are connected to what).

I've never seen any of the 916A0E1 upgrades in person, so any pictures you can provide on the harness routing connector mounting/termination locations would be helpful. Maybe I can get some more lessons learned from your pics and do a better job installing it than RRAD did for their upgrade program.
Thanks again for your help, I'll report back as I make progress.