I am having transmission problems. Yesterday, while taking off, the transmission was causing the coach to jerk and jump. The gear numbers were flashing. I checked the codes, oil was ok, the D1 showed code 3500, D2-5 didn't show any codes. I manually shifted to second gear and shifted manually to the campground, I didn't use first gear.
Code 3500 shows to check:
*ECM connections are tight clean and undamaged
*VIM same as above
*wiring has correct power and ground connections
Where are the ECM and VIM boxes located on the coach and connections on the transmission?
Another problem I have had was the retarder switch didn't light up but retarder worked normally. I checked bulbs and changed relays and didn't fix it. With this new problem the retarder doesn't work.
Thanks for all the help
Ron
Ron,
I don't know where the Allison ECU (or the VIM?) is located on your coach, but perhaps the document linked below might help your trouble shooting efforts:
Transmission - Allison MD 3060 Troubleshooting Manual [Page 7] | ManualsLib (https://www.manualslib.com/manual/1354071/Allison-Md-3060.html?page=7#manual)
Here's where the ECM is on a 97 and the connection point on the transmission end. Don't know what a VIM is.
jor
ECM: You'll likely have to remove a carpeted plywood cover that is velcro'd on.
Transmission: It's on the driver side.
jor
If all else fails....American Shifty Corporation | North Little Rock, AR (http://www.americanshifty.com/)
They are in Little Rock. I am told they know all there is to know about the /Allison trans.
If you take it to a shop Ron you have American Shifty on Broadway North Little Rock and United engines at 9401 I 30. Both are Allison dealerships but I've used neither for Allison. I would talk to both and make a decision. I've used them both for semi gears with no negative results. Good luck.
Your ECM should be at the top of the water pump compartment.
Thanks for all the replies and info. The Forum is top notch. I am open to any more info anyone has.
Thanks again.
Ron
If it was/is jerking and jumping I would make sure the bearing in back of the transmission harmonic balancer is not loose,it can be checked with a pry bar.
UPDATE:
I have a metal plate with a couple of solenoids and three relays and a 30 amp resettable breaker that powers the ECU on the forward wall under the bed. I found a couple of corroded connections on the solenoid and breaker was rusted. I replaced the breaker and cleaned up the connections, including the ground cable, and put dielectric grease on all connections.
The voltage from post to ground was 13.2 volts but when I checked from the wire lug to ground was 9.8 volts after repair voltage was 13.2 both places.
For future reference always check voltage or continuity on the wires not posts.
I want to thank everyone that responded and thanks for your help.
ECM was behind the 12 volt air compressor covered by a carpeted cover then a several bundles of wires. I hope this helps others.
Ron
Congrats on the trouble shooting and finding a fix!
The 12 volt "automotive" wiring diagram (B-2126) in your owners manual should show that 30 amp circuit breaker. If it does, make a hand written notation on the diagram indicating the fact that it powers the ECU. Might be a help to some future owner of your coach, or even to YOU if your memory is anything like mine (IE selective...)
What an excellent point. Thanks for sharing.
Richard
Please post photos if not too inconvenient. Someday someone will be searching for help with a similar or identical issue and a photo of the relays and breaker might prove to be the key that gets them smoothly down the road. ^.^d
Don
Good post to bookmark.
Don
here is the pictures as you requested for my update. Look close behind the terminal with blue zip tie at the corrosion and the 30 amp breaker that is rusted between the blue and yellow zip ties.
Thanks for the follow through. I redid that electrical component panel a few years back. I did this as part of a larger charging system project. Here is a link to the topic (with pictures including those below) which may be of some use to you as you decode what does what on that panel.
Charging System project (http://www.foreforums.com/index.php?topic=34545.0)
Don
Don
Thanks for the Charging System project link and for the labeled pictures. They are greatly appreciated.
Ron