Allison MD3060 TCM issues

[bb12489]

Hey guys,

I was about to go pickup a partial conversion this weekend (20in roof raise, framing, insulation, appliances included). Basically a screaming deal. It's a 2002 Thomas Safty-liner with the CAT 3126 and MD3060 Allison transmission.

The guy who has it called me today, after talking back and forth for a bout a week, and mentioned that when he went to move the bus, he noticed that the transmission was not shifting smoothly. He did mention that the bus previously ran just fine when he drove it from TN, but that he did have to replace the TCM at one time. He said he found one on ebay to throw in as a replacement. This is when the transmission issues started. It just seems to shift hard now, but shifting manually into gears seem to be fine.

He said he talked to an Allison tech that mentioned the TCM had to be re-programmed to work properly, but only a licensed Allison transmission dealer could do that.

At this point I'm pretty bummed, since we were planning to go pick it up tomorrow, and not this happens. The guy was at least nice and honest to let me know that this is an issue, and that I probably shouldn't bother coming down now. I told him I'd make this post to source some ideas of what the issue could be. He's sending me all the information he has on the TCM models, and what he did. I'll post all that when I get it.

I'd like to not miss out on this amazing deal of a bus, but if there are transmission issues, then that is a whole other story. Should I even bother investigating this issue? Or is this something that could be an easy fix? Could this simply be that the TCM has to re-learn the shifting patterns?

Thanks for all your input. It's much appreciated.

[fo4imtippin]

You need the original CIN or the CIN from same engine and trans. An Allison dealer can program a replacement for typically around $350. PCMPerformance can usually do the same if the dealers are giving the runaround.



If the problem is just TCM, I would ask for $1400 off the price as PCMPerformance will sell you a brand new one with programming for about $1400.


If you do nothing, the TCM will not autocorrect until it's programmed right. It could be setup for a whole different RPM motor and will continue to adapt to that..

[bb12489]

Originally Posted by fo4imtippin

You need the original CIN or the CIN from same engine and trans. An Allison dealer can program a replacement for typically around $350. PCMPerformance can usually do the same if the dealers are giving the runaround.



If the problem is just TCM, I would ask for $1400 off the price as PCMPerformance will sell you a brand new one with programming for about $1400.


If you do nothing, the TCM will not autocorrect until it's programmed right. It could be setup for a whole different RPM motor and will continue to adapt to that..

Thanks for the reply on this. Should I be worried about getting this bus back home? It would be a 190 mile trip. About 3 hours. Should I just shift manually as needed?

Also, where would I get the CIN? Is this on the original TCM? I'm sure he still has that.

[fo4imtippin]

Well you can't really shift manually, it's more of a top gear limit. I would defer to Chris or someone that knows if driving with the wrong programming will be an issue..


I would say, once your in 5th, just try stay in it for all 190 miles so you don't have to worry too much. If it's a big deal, delay your pickup a week until you have a programmed TCM mailed to you..

[bb12489]

Originally Posted by fo4imtippin

Well you can't really shift manually, it's more of a top gear limit. I would defer to Chris or someone that knows if driving with the wrong programming will be an issue..


I would say, once your in 5th, just try stay in it for all 190 miles so you don't have to worry too much. If it's a big deal, delay your pickup a week until you have a programmed TCM mailed to you..

I feel mostly confident that the trip will be alright. I'm going to move the bus around a bit and get a feel for it before we finalize our deal and take off. The replacement/re-programmed TCM is the first thing I'm going to do once we get back home with it.