Where to have TCM/TCU rebuilt? Or order a new one?
Posted: Tue Mar 09, 2021 7:33 pm
Hey Gents,
Been helping my cousin remotely trouble shoot his rig. As well he’s contacted a local Allison shop he trust. Reaching conclusion his rig’s issue is a temperamental (literally) Transmission Electronic Control Unit. Do you know of a current electronic repair facility, and/or site to order a unit from? He’s checked this business (see pix) but appears they are no longer in business.
By now many of you are full of questions about what has or hasn’t been checked. So I’ll explain, but responses to the initial question are appreciated. At this point I’m thinking some of the large salvage yards for a used unit may be the answer.
Ok, his tranny set up is essentially identical to mine. My rig is a ‘95 Continental, 8.3L, MD3060. Our tranny’s s/n are literally a few digits apart from each other and have the same shift pads. His rig is a ‘94 WB Vectra, 5.9L Cummins (1 Chassis, 2 House batteries.) So the issue at had is a temperature issue. During morning cold, say in 30’s rig will not start. No trans pad lights, no VIM relays latching, nada. Wait till noonish, 15-20 degrees warmer the rig fires right up.
Initial fault this past week, he was at tire shop getting ready to get his 6 year old front tires changed out when the rig would not start, some flashing lights in dash, and rpm gauge bouncing. Story here was he discovered the exciter and the rpm wires had come off of his alternator. He repaired those. But appears these broken wires may have induced other issues. Keep reading please (thanks!)
Using our excellent historical resources here (have read of Mel’s issues and repairs, Brett’s recommendations, Jim and John’s follow up comments in numerous others in the older blogs dealing with this issue.) To date we have verified battery voltages are good/excellent; tested the VIM 6 relays; replaced two dif’t solenoids (both appeared to have been worthwhile replacements as when shook they rattled;) verified two fuse links are good; replaced all 6 VIM relays with new ones; cleaned multiple battery contact terminal lugs; and replaced the ignition switch. Ok, some of these had been a need for and culminated with this issue.
The temperature issue appears to be reality as Groundhog Day has occurred daily for the last 5 days. The Allison shop tech noted he’d experienced a similar issue with his rig and had used his wife’s hairdryer to warm the TCM/TCU unit for several minutes with the positive results of the rig starting. So tomorrow morning my cousin will be verifying once again his rig doesn’t start, then follow the hairdryer steps to warm and see if then starts. Now we are back to my initial question, who repairs, where to buy?
I’d like to also ask if any of you have the schematics to this unit and are aware of what components may actually cause such a problem? I can do electronic component replacement down to the mini-soldering level and as long as we can get our hands in the components and the PCboards are single layer then I should/may be able to do the repairs.
Appreciate y’all taking the time to share your KSA’s.
R/Willie
‘95 Continental, 8.3L (mine since ‘99/‘00)
Been helping my cousin remotely trouble shoot his rig. As well he’s contacted a local Allison shop he trust. Reaching conclusion his rig’s issue is a temperamental (literally) Transmission Electronic Control Unit. Do you know of a current electronic repair facility, and/or site to order a unit from? He’s checked this business (see pix) but appears they are no longer in business.
By now many of you are full of questions about what has or hasn’t been checked. So I’ll explain, but responses to the initial question are appreciated. At this point I’m thinking some of the large salvage yards for a used unit may be the answer.
Ok, his tranny set up is essentially identical to mine. My rig is a ‘95 Continental, 8.3L, MD3060. Our tranny’s s/n are literally a few digits apart from each other and have the same shift pads. His rig is a ‘94 WB Vectra, 5.9L Cummins (1 Chassis, 2 House batteries.) So the issue at had is a temperature issue. During morning cold, say in 30’s rig will not start. No trans pad lights, no VIM relays latching, nada. Wait till noonish, 15-20 degrees warmer the rig fires right up.
Initial fault this past week, he was at tire shop getting ready to get his 6 year old front tires changed out when the rig would not start, some flashing lights in dash, and rpm gauge bouncing. Story here was he discovered the exciter and the rpm wires had come off of his alternator. He repaired those. But appears these broken wires may have induced other issues. Keep reading please (thanks!)
Using our excellent historical resources here (have read of Mel’s issues and repairs, Brett’s recommendations, Jim and John’s follow up comments in numerous others in the older blogs dealing with this issue.) To date we have verified battery voltages are good/excellent; tested the VIM 6 relays; replaced two dif’t solenoids (both appeared to have been worthwhile replacements as when shook they rattled;) verified two fuse links are good; replaced all 6 VIM relays with new ones; cleaned multiple battery contact terminal lugs; and replaced the ignition switch. Ok, some of these had been a need for and culminated with this issue.
The temperature issue appears to be reality as Groundhog Day has occurred daily for the last 5 days. The Allison shop tech noted he’d experienced a similar issue with his rig and had used his wife’s hairdryer to warm the TCM/TCU unit for several minutes with the positive results of the rig starting. So tomorrow morning my cousin will be verifying once again his rig doesn’t start, then follow the hairdryer steps to warm and see if then starts. Now we are back to my initial question, who repairs, where to buy?
I’d like to also ask if any of you have the schematics to this unit and are aware of what components may actually cause such a problem? I can do electronic component replacement down to the mini-soldering level and as long as we can get our hands in the components and the PCboards are single layer then I should/may be able to do the repairs.
Appreciate y’all taking the time to share your KSA’s.
R/Willie
‘95 Continental, 8.3L (mine since ‘99/‘00)