ALLISON MD 3060 ELECTRONIC TRANSMISSION
Corrosion found in Vehicle Interface Module
The Vehicle Interface Module or VIM is a self contained pre-wired control box that simplifies the connections between the Electronic Control Unit [ECU] and the vehicle electrical system.
The operator experienced a high transmission temperature with no high idle and exhaust brake. The fault codes indicated a power interruption between the battery and ECU.
The VIM {pictured above} showed signs of corrosion at the connector and inside the unit, the VIM must be replaced.
Corrosion inside the VIM
This unit is located along the frame above the front axle. Freightliner {Now the Thomas Bus dealer} knows about this problem and is making improvements. MD 3060 transmissions do not like any kind of moisture since the components are electronic.
Our company has 6 2003 model year HDXes (mercedes 906/md3060) with the same issues on the VIM box corrosion. Thomas has been no help to us on any of the myriad of issues we've had with them. I solved the problem with the VIM box corrosion though. The VIM was originally designed to be placed in the dash fuse panel area, the box is therefore non-water resistant. But since they went and put it in the stupid mid-front-axle box, it receives massive amounts of salt spray from the front wheels. To correct this, take a brand new VIM box, and a can of permatex instant gasket or other RTV sealant (I like the permatex because it skins fast). Fill ALL the underside vents with a nice fat bead of it. Let dry. When you install the boxt to the bus panel by the front axle, dont forget to also fill the 4 bolt holes with some RTV as well, since the bolt holes go from INSIDE the box, to the outside environment. The connectors themselves are well sealed, but I still pack them with 3m silicone grease. Good luck! -Daniel
ReplyDeleteJohn,
ReplyDeleteI'm installing a MD3060(2001 WTEC 3)in a '95 international 4900. I have everything figured out with the exception of the VIM wiring. It is a 4 plug like the one shown above. The only wiring diagram offered by allison is for a 2 plug vim. Do you have access to the diagram for the 4 plug.