Allison transmission problems

[rwcarroll22]

I have a 2000 Allegro Bay 5.9 cummins with a Allison Transmission. We just bought this and on our first trip two miles from the house the transmission went into shift inhibit mode and will only go into reverse. It was running great just before this. I had it scanned and it showed codes P0722 output speed sensor no signal, P1721 solenoid B controlled clutch not enaged, and P0701 transmission control system performance. I changed out the output speed sensor, did not help. It's on a freightliner chassis. I'm at a loss as to what it could be. Thanks in advance for the help.

[Bigd9]

Sorry it had to be a problem that brought you to the iRV2.

My Allison did something similar except it would go into first gear, but not any higher. I called Allison and a very knowledgeable technician stepped me through the code checking. He gave me a mixed bag of what it could be wrong. He thought it most likely was a internal speed sensor and it would require a transmission dissemble to replace. But luck was on my side. While the tow truck operator removing the driveshaft he noticed the wire going to the external speed sensor, the same one you replaced, was broken. At the Allison dealer the wires had to be cut and splice and all was good with the world again! Simple fix.

Anyway I hope yours is a easy fix.

[Skip426]

Welcome to iRV2.

Sorry your first post is about problems .

Three codes , that could all be about poor connections in the transmission control wiring harness.
Is your transmission a 3000 series ?
Were you able to retrieve your own codes from the shift pad , or do you have a lever shifter ?

[edgray]

Welcome to iRV2. Use the red triangle found below your screen name of your post to request the MODS move your thread to the Allison forum, where you may find expert help. It will help if you can add the model of Allison you have

[gnvrvin]

Ed

First things first:


lots of knowledgeable folks here

And yes posting in the Allison forum may be best.


This is from a Provost forum back in 2010:

michaeldterry
01-15-2010, 06:35 PM
Good news/bad news... bad news first - The mechanic/technician from W.W. Williams called me this afternoon and said he had researched my symptoms and it sounds like I need a new shifter module. His location did not have one in stock and the closest location that does is in Alabama. He's having the part air freighted in to arrive tomorrow and is having it delivered to his home. When it arrives, he will call me and arrange to come to Woodstock and put it in (he is in Atlanta - about 30 miles from me).

Now the good news - he told me that I could try using the blunt end of a writing pen to push hard on the "D" pad and sometimes that would work as a temporary work-around. I grabbed a pen off my desk, headed to the bus, started and warmed her up, then held my breath and used the pen to push the "D". After poking around (literally "poking it with a stick") a bit, it clicked into gear! Yea! To make sure it wasn't a one time fluke, I shifted to Neutral and then poked "D" with the pen again and it eventually went into gear! Success! Now I was feeling brave to I took her to get fuel and then brought her home to load for the trip to Chattanooga tomorrow. We will decide what to do about the W.W. Williams guy coming out tomorrow depending on what time the part arrives. If it arrives in time to still get us on the road before 4:00PM, we can make our commitment in Chattanooga tomorrow night. If the part arrives too late to get us safely on the road in time, I've decided to take my chances with the "pen poke" work around and have the shifter replaced next week after we return.

Something to try perhaps. Try rolling and pressing with a finger firs then if no luck try the pen trick? And I imagine the blunt end of a pen is the type with the press in cap on the none writing end not a clicky pen end

Here is a link to the full thread..good read:
http://forum.prevostownersgroup.com/...hp/t-4293.html

Good luck,
Greg

[rwcarroll22]

Thanks for the response. Unfortunately mine doesn't have the push selector. It's the lever on the dash. I'm trying to figure out how to move this post, but a don't see an orange triangle below my name.

[rwcarroll22]

I had someone scan it and read the codes. It has a lever shifter and I'm not sure how to tell which series trans i have.

[rwcarroll22]

It appears to be a MD3060. At least that's what the paplet i found in the motorhome says.

[rwcarroll22]

Correction, I have a series 1000. I just crawled under it and looked at the plate.

[Skip426]

Originally Posted by rwcarroll22

Correction, I have a series 1000. I just crawled under it and looked at the plate.

Sorry I missed seeing this when you posted , 1000 series , that's odd , if it wasn't a 3060 I'd have expected a 2100/2500 series .
But reading through the PDF I do see a 1000 MH listed .

Anyhow , I only have an operators manual for the 1000/2000 series , and it's pretty shy on diagnostics and repair .
My former neighbor was a mechanic at a GM dealer and I recall they had a bunch of problems ( approx 2004 )with water intrusion into the NSBU ( Neutral Start and Back Up ) module , but that caused a default to second gear.
I hope your not still stuck on road side and here's the PDF just in case it's any help.

[rwcarroll22]

Thank you for the information. Unfortunately it is still in a parking lot there but it is only two miles from my house. I sent my computer off to transmission instruments after calling them to verify they could check and repair the TCM to get a call from them late yesterday afternoon that they didn't work on this model. I was able to find another company close to that one that did. The TCM is being shipped to them and I'm hoping they can get it fixed and shipped back to me next week.

[rwcarroll22]

Well the problem finally got solved, ended up needing a whole transmission. I got a reman Weller with two year parts and labor. 5k later we are back on the road. Thanks for the responses.