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-   -   Limp mode only when towing otherwise fine, HELP (https://www.dieselplace.com/forum/57-gm-transmissions/41-allison-oem/975554-limp-mode-only-when-towing-otherwise-fine-help.html)

firedreamer 04-28-2019 03:47 PM

Limp mode only when towing otherwise fine, HELP
 
OK folks need some help. Have owned a 2005 3500 Silverado dully for 3 years without problems. 163000 miles on the completely stock Duramax / Alison 1000 setup. The last month or so it has gone into limp mode but only when I start to tow our 5th wheel. It will reset if i pull over and turn it off for a min or two but I have only let this happen about 3 maybe 4 times. It will drive all day long and hundreds of miles at any speed without towing. All normal shifting, So I had the error codes pulled and get the classic P0700 from the ECM and so I know that means a internal trans error code and the local Alison shop will pull that code for me this coming Tue for $75 versus the Chevy dealers $100.
So here is my question, Is there anything that could possibly be wrong inside the trans like a solenoid or maybe the TCM needing to be re-flashed or replaced or something that could cause this without needing to do a complete rebuild? I just don't have the $ to do a complete rebuild right now, but something short of that , maybe. I don't mind spending the $75 if there's any chance they could find a cheap repair but if there's no chance at all short of rebuild and it's drive it for now without towing or rebuild I would rather not spend the $75 right now. THOUGHTS ?
Thanks for your suggestions

OkDually 04-28-2019 03:51 PM

Quote:

Originally Posted by firedreamer (Post 9816594)
OK folks need some help. Have owned a 2005 3500 Silverado dully for 3 years without problems. 163000 miles on the completely stock Duramax / Alison 1000 setup. The last month or so it has gone into limp mode but only when I start to tow our 5th wheel. It will reset if i pull over and turn it off for a min or two but I have only let this happen about 3 maybe 4 times. It will drive all day long and hundreds of miles at any speed without towing. All normal shifting, So I had the error codes pulled and get the classic P0700 from the ECM and so I know that means a internal trans error code and the local Alison shop will pull that code for me this coming Tue for $75 versus the Chevy dealers $100.
So here is my question, Is there anything that could possibly be wrong inside the trans like a solenoid or maybe the TCM needing to be re-flashed or replaced or something that could cause this without needing to do a complete rebuild? I just don't have the $ to do a complete rebuild right now, but something short of that , maybe. I don't mind spending the $75 if there's any chance they could find a cheap repair but if there's no chance at all short of rebuild and it's drive it for now without towing or rebuild I would rather not spend the $75 right now. THOUGHTS ?
Thanks for your suggestions

I would call and ask your local auto parts stores if they have a scanner that can pull TCM codes.
If they do, then go get the codes pulled for free and post them here

:thumb:

D_R_C 04-28-2019 04:27 PM

My ? would be are you using towhaul when towing ?
If not then start using towhaul when towing, Allison will suggest the same.
And yes, try to get the TCM codes read.
What's actually wrong :confuzeld don't know until you get the code numbers.
And the repair cost, same answer as above.

Ron Nielson 04-29-2019 12:04 AM

What is the total weight if your fifth wheel when you are using it? And where do you live and tow your fifth wheel?

G2GBY 04-29-2019 08:57 AM

P0700 is the TCM requesting a MIL (Malfunction Indicator Light aka: "check engine"). All the 700 code does is tell the ECM "something's wrong" and to illuminate the MIL. There is another code in the TCM that you need to pull that will actually tell you what the malfunction is so.

Like said above I go to a local parts store to have code read for free. If one place can't read it I go to another. Seems like there all stack up in a row by us.

Report back with code.

dmax3500 04-29-2019 09:42 AM

where are you located?


maybe a member has a ''tech2'' scanner and can look at it for you

firedreamer 04-29-2019 01:25 PM

Answers - yes I use the tow mode the rv weight is 14,500 loaded out, we are full times but base is in the PNW but last year we traveled about 15,000 mile down through the south west and over to mid-west areas. I have called 3 parts stores and they all tell me they only have the most basic readers so nobody can read the TCM codes so far but i will make more calls

Ron Nielson 04-29-2019 02:35 PM

Quote:

Originally Posted by firedreamer (Post 9816834)
Answers - yes I use the tow mode the rv weight is 14,500 loaded out, we are full times but base is in the PNW but last year we traveled about 15,000 mile down through the south west and over to mid-west areas. I have called 3 parts stores and they all tell me they only have the most basic readers so nobody can read the TCM codes so far but i will make more calls

Autozone aand OReilly usually have very capable scanners by Bosch.



You are towing pretty heavy and your trans is slipping, meaning the steels and clutches are wearing out. The more this happens, the more often it will become, until you need to rebuild the trans. Kep the throttle pressure light at shift points, let next gear engage before applying more engine power. There are kits that will increase the line pressure to help the clutch packs hold, but once they start to slip on a regular basis, I don't think they help much.

Rvn4me 04-30-2019 08:12 AM

Quote:

Originally Posted by firedreamer (Post 9816834)
I have called 3 parts stores and they all tell me they only have the most basic readers so nobody can read the TCM codes so far but i will make more calls

You must visit if all possible. Most places don’t even know what there units are capable of. Advance auto usually lets me use there Actron Elite AutoScanner Part #CP9690 because there to busy.
Just was pulling our 5er into Hocking Hills Ohio and threw a P0732. You never know what code your going to get pulling. They aren’t the normal codes. First place only could read P0700 second place they didn’t know if the could read a trans code but they did.
Now I need to get it rebuilt.

D_R_C 04-30-2019 11:24 AM

Driving around town possibly waisting fuel and time if the first one or 2 don’t have the tool to read TCM, or just drive to the place that has the scanner that reads TCM.
I don’t think a basic scanner can read TCM, basic OBD2 scanners are what most auto part have, where I live.
Where most shops have the ability to read everything having the proper software, but this comes at a cost, not free.

Allison might wave the fee, if they end up doing the repair.
Something to consider checking out.


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