Allison transmission no go


villelobos

New Member
Help! Looking for info on an allison tranny, 1994 Monaco with a Cummins 250 hp and World 6 speed. Initial symptom was tranny dropped out of 6th gear and lockup, speedometer failed to zero, do not shift light came on and the control panel/ ECU is dead, no LED indication at all. Limped in a few miles in 5th (Ithink), no lockup and parked. At one time on the limp in the speedometer went nuts, read max plus and the odometer was clicking off tenths wildly, then back to zero mph. I have found a relay board on the firewall and removed and checked all relays, they seem fine. Both 15 amp fuses on the board are OK, one has power full time and the other comes hot with ignition on. I haved removed the ECU/ control panel and checked the black wire (appears to be chassis gnd, and is a solid gnd) Unpluged/ reset all ECU and relay panel connections, no good and no change. Looked at the wires heading into the tranny, see no obvious problems. Any input is appreciated, Thanks!
 
G

Guest

Guest
RE: Allison transmission no go

Do u have any ck engine lights on ????
If so pay to have it scanned ,, don't use autozone or advanced..
If it has codes ,, let us know what they are ..
I have seen the instrument clusters fail ,, they are what they call the C-buss system ,, it links the PCM BCM and SCM together at one source ...
It sounds more likely u have a shorted to power or ground ,, speed sensor ,, if can take a really good look at the harness going to the trans ,, cause sometimes a nail wil find a wire and not have a prob ,, till it finally hits bare wire ,, They don't always watch when they build these things ,, they just start shooting nails until it built ,,, please post back on the findings... :)
And welcome to the forum :cool: :)
 

villelobos

New Member
RE: Allison transmission no go

Hi Folks, Problem solved! It was the transmission ECU, or main computor located under the shift pad. Thanks a million to Ted at TKT transmissions in PA. He took all of my info from the computor anf reprogramed me up a used but good replacment for under 1/4 of a new unit! What a deal. The swap was simple, just needed a few torx bits and a little time. Thanks Ted!
 
G

Guest

Guest
RE: Allison transmission no go

Good to hear it is fixed ,, i would have mentioned the ecu in my post ,, but u hardly see them go out ,, it's usally a wring prob ,, but then again at least it's fixed :approve: :)
 
Top