So my fire dept has a '92 Freightliner with an Allison MD3060. Has really low hours and miles on it (this is just an FYI). The transmission has a push button control head. Coming up with Cat's Eyes on the control head. Tried plugging into it with the Allison software using Nexiq USB II bluetooth and the 12 pin GM connector that was the thing back in the 'day'. Not connecting. Pushing the Arrow keys (up and down simultanously) doesn't come up with codes either. SO.......anyone had any experience with said problem?? And, here's the fun part; Allison discontinued this model back in 2002 and let their parts deplete over time (heavy sigh). I am leaning towards the computer, since the control head isn't talking with the ECM and I can't come up with any codes. So turning on the master switch and then the key switch it flashes quickly from 'NN' on the display to CAT EYES and 16 quick beeps. Cycling the key switch it just goes right to CAT EYES and the 16 beeps. I've tried using the 1903 and 1708 (I think that's what they are) protocols on the software, still not talking. So any help would be appreciated, Thank you!!
I just got done working on a Gen 5 allison with the cateyes. Mine turn out to be the 80 pin connector at the TCM. I would double and triple check your connector. Mine looked like new as the truck hasn't got 100k miles yet. Turns out they have a perfect fit between the male/female pins in the connectors. They even went so far as to make a tool to check pin drag. Allison doc would not read my trans. problem either. Find your main connector and have a look. Wiggle the connector, and hold it together with the key on to see if that gets the NN back.
So Monkeywithawrench, I done a little more digging on your tranny and you have two connectors on your Ecu. A and B and they are lettered as such. Unplug them and with the ignition switch in the off position you should have battery power at pins B2 and B11. Make sure its at least 14 volts. Check pins B9 and B18 to make sure they go to ground. If all checks out turn ignition switch on and you should have battery voltage to pin B12. Check this out and report back.
Thanks Grandpa!! I was going to head over to the fire station today and check that out. Yesterday I had taken all the radios and extraneous switches that usually gets scabbed on without thought of their location or how a mechanic is going to access everything under the dash covers these things have been sheet metal screwed too!! "Lets put it there!! That looks like a good spot!!" I had found the TCM and unplugged and plugged the connectors a few times and wiggled them a bit..........no joy. Just didn't have all my tools with me since those were at the shop. Also found the big round multi pin on the firewall and unplugged, inspected, wiggled, and plugged it back in. No joy. I did find a link for trouble shooting the MD3060 with WTECII at transmission Instruments which showed pinouts and tests. https://www.transmissioninstruments.com/wtecii/ I'll let you know what I find out.
I copied and pasted the info from Transmission Instruments for the Allison MD3060/WTECII troubleshooting. Hope this helps somebody else in the future. https://www.transmissioninstruments.com/wtecii/ WTECII Instructions for WTECII system (two digits on Your shift selector) Recommended tools : For 1992, 1993, 1994, and early 1995 models if experiencing erratic or no display; especially when there is cold weather or have retrieved any trouble codes. Have you seen code 69-32 already? Stop troubleshooting = 100% defective ECU! Assemble 12V/15-25W light bulb (spare brake lamp bulb or similar – #1156, #1073 etc.) with 20 gauge solid copper wire (ordinary hookup or “bell wire”). Strip 1/2″ on test side. When you check ECU connectors, the lamp must glow bright white light. A dim light will indicate a bad connection somewhere; likely due to oxidization. A voltmeter will not indicate bad connections. An ordinary voltmeter or VOM isn’t reliable for this test. However you will need one to check the lower voltage systems. After assembly, check lamp directly on your battery terminals. Caution lamp will become HOT! Always disconnect the battery or turn off the battery switch (Power Train Battery) prior to disconnecting or reconnecting ECU connectors! Locate the ECU (in most RV’s the ECU is mounted directly to the shift pad). If remote shift selector is used, ECU may be nearby, close to VIM Module or mostly on trucks is mounted close to the transmission (just follow bundle of wires from transmission). Disconnect the battery first, then unplug the two oval shape ECU connectors and reconnect the battery. Check the B connector with black plastic rear side for the numbers (the other side backing A connector is either white or blue). Only 8 numbers from 34 are imprinted (both sides of the row). Insert test lamp leads into corresponding B connector sockets: 9 and 2 then 18 and 11. Next turn “ON” Ignition switch and insert test leads to 9 and 12. #9; #18 = BATTERY GROUND; #2; #11 = BATTERY POWER; #12 = IGNITION If lamp is bright, the ECU is probably defective unless the display itself is defective. There is no practical method to check display on the vehicle except to swap selector from another vehicle. But, if you do have a remote shift selector, you can check the display using ordinary 9V battery and hookup wire. Remove the two 10 amp fuses from the Vehicle Interface Module (2950986) and connect the 9V battery using bell wire slightly bent on ends; so they can hold inside connector sockets. Negative 9 volt terminal to B connector #9 and 9 volt positive terminal to B connector #2 and A connector #8. After a few seconds remote shift selector should start beeping and show on display “cat eyes “. Just be sure that you have a good connection with wires and sockets. If display comes “ON”, ECU is defective.
If it turns out to be the Tcm, don't give up hope. You can have it rebuilt or go thru an exchange on it. A good Allison dealer with have that exchange. You could also take your Tcm and have them test it and if it turns out bad, have them program you another when your there... Good Luck
No, not giving up hope. Fortunately, this truck isn't a front line piece..........BUT it is setup for chimney fires, and since it was 0F last night YOU KNOW the fire places and woodstoves are working overtime. I HATE HAVING FIRE TRUCK DOWN!! But, I guess that's what mutual aid is for. I will report back later on my findings.
Went out today and tested power and grounds. All good. Pulled TCM and remote push button control and sending them out to Transmission Instruments tomorrow. I'm going to overnight down to Texas. I've read some good things about this company on different RV forums. He's pretty good with the MD3060 transmissions. He said he could have it back to me in a day or 2.
Thanks for the update....keep us posted.
So I overnighted the Transmission Control Unit and the shift pad down to John in Texas. Sent them out Tuesday 2/2/21. He got them Wednesday. Started working on them that afternoon. Finished them Thursday, shipped them out, I got them Friday and back in the truck they went. Address: Transmission Instruments 6101 Long Prairie Road, Ste 744-185 Flower Mound, TX 75028 Phone: +1-(972) 353-8286 Email: [email protected] I asked him specifically what component had failed and he stated their were a few capacaitors that were bad. What he said he does is go through the entire unit, replaces all the capacitors because they do leak over time (I can validate this from experience), checks the board and resistors, tests them, and off they go. I've read reviews back as far as 2014 so he's been doing this for a while. And he gives a 2 year warranty!!(Better than Allison!!) When I plugged in Allison DOC, their was a left over code of 69-33 (or 32)....can't remember for no communication with control module. Cleared that out, cycled the ignition and master switch a few times.......no codes. Checked data bus traffic......all good. Road tested the truck and it performed just as it should. I kept watching the shift pad.........the transmission would only go up to 5th gear (which is what its programmed for) and thought to myself 'Hhhhmmmm, maybe I should have had him unlock 6th gear...........WAIT...it's a fire truck. They don't need to be going 70mph.' So the rebuild for WTEC II TCM was $550 The remote shifter was $159 Shipping was about $90 overnight UPS. Prompt, no extra charge for 'rush'. So John gets my future work with Allison electronic systems. Hope this helps someone else in the future!!
Thanks for sharing !
Yes, thanks for responding and am glad you got it back in service.