Allison transmission trouble

[Capt. Rich]

Hello all, Just ran 1300 miles. The Allison tranny in my 2008 Seneca started acting up. It seemed to slip out of overdrive. Next it started acting up in 3rd and 4th, shifting erratic. The speedo would drop to almost zero with every erratic shift. At one stop it would not shift into any forward gear for awhile. I checked the fluid and it is clear and did not smell burned. I shot the bell housing and it was about 130 degrees. The transmission warning light( open end wrench and trans icon) started blipping on and off but did not stay on. The rig has 36,000 miles on it. I have tried some forum troubleshooting and it sounds more like an electrical gremlin than mechanical. Any thoughts would be truly appreciated.
Thanks, Capt. Rich
P.S And a Merry Christmas to all.

[Grumpy]

Originally Posted by Capt. Rich

Hello all, Just ran 1300 miles. The Allison tranny in my 2008 Seneca started acting up. It seemed to slip out of overdrive. Next it started acting up in 3rd and 4th, shifting erratic. The speedo would drop to almost zero with every erratic shift. At one stop it would not shift into any forward gear for awhile. I checked the fluid and it is clear and did not smell burned. I shot the bell housing and it was about 130 degrees. The transmission warning light( open end wrench and trans icon) started blipping on and off but did not stay on. The rig has 36,000 miles on it. I have tried some forum troubleshooting and it sounds more like an electrical gremlin than mechanical. Any thoughts would be truly appreciated.
Thanks, Capt. Rich
P.S And a Merry Christmas to all.

Join this group on Yahoo and ask you question lots of KODIAK owners there

https://groups.yahoo.com/neo/groups/SuperCrvgroup

[Dustdevil]

I agree that it does sound more likely to be electrical than mechanical. Wouldn't have a clue where to start, though. There are diagnostics built into the sophisticated code reading equipment usually present at the larger medium duty truck dealers. Unfortunately, they are also quite proud of their services.

[abarkl]

It could be as simple as a comm failure between a sensor connected to the Allison and the TCM. Or just disconnecting and reconnecting the main bus may also prove to be the solution.

The Allison transmissions are known to be rock solid mechanically and of the 3 we've had of different generations and sizes, not a problem one.
We did think we had a problem with the 3000 in our diesel pusher but it turned out the bucking and lunging was dirty fuel filters on the Cummins engine.

The Seneca has the Allison 1000.

Let us know what you find is the problem.

[jasum]

I do NOT have a motor home, but my truck did that type of thing one time. It turned out to be some kind of sensor needed replaced.

Good Luck

[Capt. Rich]

Hello All,
I replaced the speed sensor to no avail. Now the trans won't shift into any gear. It shifts and then when you go to accelerate it goes into neutral. I am having her towed to a Chevy dealer tonight. Is there anything I should do in particular before it goes on the hook?

[Grumpy]

Originally Posted by Capt. Rich

I am having her towed to a Chevy dealer tonight. Is there anything I should do in particular before it goes on the hook?

Go directly to ALLISON. When we had our SENECA I was told Chev couldn't work on it, had to go to ALLISON.

[Capt. Rich]

Towed the rig to an Allison shop. He did a diagnostic on the TCM and it showed no power. He disconnected it and bingo everything shifted and no service trans light. I told him I did that the day before and nothing happened. He said it could be an ignition lead, battery lead and one other I can't remember. He thought the problem could be fixed but gave no assurance. He said the Duramax wiring is the weak link. The trans itself is fantastic. He did not charge anything which was good and bad because he did not think he resolved the problem.
We started south at 3:00 today. Made it 20 miles and the trans started to do the same thing. We limped in to a Chevy dealer and the tech said this is sort of a common problem with the Kodiak Topkick. He confirmed what the Allison tech said about the poor wiring harnesses. They will look at it tomorrow.
Adventures in RVing. to be continued!!!

[Grumpy]

Originally Posted by Capt. Rich

Towed the rig to an Allison shop. He did a diagnostic on the TCM and it showed no power. He disconnected it and bingo everything shifted and no service trans light. I told him I did that the day before and nothing happened. He said it could be an ignition lead, battery lead and one other I can't remember. He thought the problem could be fixed but gave no assurance. He said the Duramax wiring is the weak link. The trans itself is fantastic. He did not charge anything which was good and bad because he did not think he resolved the problem.
We started south at 3:00 today. Made it 20 miles and the trans started to do the same thing. We limped in to a Chevy dealer and the tech said this is sort of a common problem with the Kodiak Topkick. He confirmed what the Allison tech said about the poor wiring harnesses. They will look at it tomorrow.
Adventures in RVing. to be continued!!!

Their comment has me really wondering. Having owned a 2008 SENECA, that I put 55,000 miles on, as well as knowing over 50 other owners with all year KODIAK DURAMAX Super "C"s no one else ever mentioned that problem, or wiring issues in general.Also when I had my unit in for service at a medium duty dealer they always talked about how " bullet proof" the 5500 was. That comment was also echoed at the allison shop when they serviced the trany.

[abarkl]

Originally Posted by Capt. Rich

Towed the rig to an Allison shop. He did a diagnostic on the TCM and it showed no power. He disconnected it and bingo everything shifted and no service trans light. I told him I did that the day before and nothing happened. He said it could be an ignition lead, battery lead and one other I can't remember. He thought the problem could be fixed but gave no assurance. He said the Duramax wiring is the weak link. The trans itself is fantastic. He did not charge anything which was good and bad because he did not think he resolved the problem.
We started south at 3:00 today. Made it 20 miles and the trans started to do the same thing. We limped in to a Chevy dealer and the tech said this is sort of a common problem with the Kodiak Topkick. He confirmed what the Allison tech said about the poor wiring harnesses. They will look at it tomorrow.
Adventures in RVing. to be continued!!!

Hang in there and thanks for the update Capt. Rich!

[Capt. Rich]

The Allison tech said the International has less frequent problems with harnesses than the Kodiak. The Chevy tech mentioned harness abrasion and movement that causes problems. I can see first hand the abrasion on the main braid where it has wore away the finish on the inside of the engine hood. The Chevy tech has also seen battery cables in need of replacement due to abrasion from the chassis.
Once again, adventures in RVing

[Capt. Rich]

After reading "Christmas crash" obviously I don't have much of a problem. Thank God they are all safe.

[abarkl]

Originally Posted by Capt. Rich

After reading "Christmas crash" obviously I don't have much of a problem. Thank God they are all safe.

Being "upright" is alright in my book too!

[repacs0103]

I don't have a MH but do have an 03 GMC 4500 Duramax/Allison 1000 and a couple other GM Duramax/Allison trucks at work. On the 4500/5500 chassis there is a main harness leading from the ECM/TCM down to the trans. Goes from the passenger side firewall down past the removable fender liner and on down to the bellhousing. GM had a known abrasion issue with that section of the harness. I've repaired it on ours once myself and my dealer has done it another 2 times. All 3 times it has caused shifting/no shift issues and multiple trans codes. Another very common failure point is the park/neutral switch mounted directly on the trans at the shifter pin. It's a common issue on all GM automatics largely due to poor sealing and proximity to road spray. When it fails it can also result in abnormal or no shift issues and is typically accompanied by a malfunctioning "PRNDL" display on the dash.

In general these were pretty poorly built cabs by GM. The chassis, engine, transmission, axles, etc. are stout but the cabs and associated harnesses/parts hailed from the dark days of GM. We are moving away from all the 4500-8500 series chassis we have in favor of Ford and International because the GM stuff just doesn't hold up, at least in commercial use.

[Capt. Rich]

Just left the Chevy dealer. They found some green wires(corroded) in the harness and fixed that. When trying to download the information from the TCM it appeared to be "faulty".They have to order the new TCM from an Allison dealer and send my old one back to have the proper sim information downloaded into the new TCM. I called the Allison Global Headquarters and was told this is correct. Only an Allison dealer can do this process. I questioned the reliability of their trans. He told me the trans itself is quite durable but they had issues with the electronics and wiring. He gave me the part # for their updated TCM, that he said had alot of the bugs ironed out. No matter the problem, if the vehicle is dead in the water the reliability is suspect. There is the age factor-2008- but the rig has been gently used with only 35K for mileage. The time frame now is over 2 weeks and I am not sure of the cost. We have rented an Enterprise car and leaving for Florida tonight. I will drive back up when its done.
Adventures in RVing-to be continued.
P.S. Does what I described sound familiar and correct?

[abarkl]

Thanks for the follow up Capt Rich.
Our '07 chassis has 30K on it now so we will look for any signs of what you have mentioned.

[Grumpy]

Originally Posted by Capt. Rich

No matter the problem, if the vehicle is dead in the water the reliability is suspect. There is the age factor-2008- but the rig has been gently used with only 35K for mileage. The time frame now is over 2 weeks and I am not sure of the cost. We have rented an Enterprise car and leaving for Florida tonight. I will drive back up when its done.
Adventures in RVing-to be continued.
P.S. Does what I described sound familiar and correct?

As I mentioned earlier you seem to be the "Lone Ranger" with this issue. The people I know with similar units range in age from 05 and up and mileage in the 50-80 k range or higher and none have had a similar problem. ????

[Capt. Rich]

llstate can go blank themselves.

[Capt. Rich]

Hello All. I drove the rental car back up north on Jan, 17th. I went to Christiansen Chevrolet and talked to the mechanic. He showed me the 10 pin harness and the 3 female connections that were green corrosion. He said this probably short circuited the TCM and caused the trans to fail. They replaced the 10 pin harness and an updated TCM as advised by Allison. They also replaced the fuel filter and #4 glo plug as it was detected on a diagnostic test. $1700.00 and change later the rig ran flawlessly. 1350 miles back home and the trans shifted smoothly and went thru the Cumberland Gap at a sustained 50 MPH. Christiansen Chevrolet in Highland Ind. could not have been more gracious. They left us spend the first night camped out in their parking lot. The work took awhile because they had to order the TCM. The next road trip is over to Naples, Fl. towing a 20Ft. auto hauler, about 350 miles roud trip. I will report back after the cruise.

[abarkl]

We are glad to hear you were able to get it resolved.
Thanks for the followup.
Happy travels!