Chevy Silverado and GMC Sierra Forum banner
1 - 20 of 25 Posts

· Registered
Joined
·
14 Posts
Discussion Starter · #1 ·
Truck has been at the local Chevy dealer service center for over a month now. Where I live in southern MD is was the only place I thought I could tow the truck to. My problem started with the transmission showing an error on the DIC that I needed to put it in neutral to reset because the selected gear would not engage. There was a flashing line under the gear selected and the truck would not move. Once at the shop they tried to reflash the ECU but it would not hold the code and they put one on order. Now I am told that there are no transmission ECU's in the GM supply system and none being manufactured. They say they are still "looking" but I think I need to come up with another plan. 75000 miles on a beautiful trunk so I hate to let it just go. Any suggestions, or is an example of the new technology age creating an obsolescence issue forcing us to buy a new vehicle every 10 years? Thanks.
 

· TOTM
Joined
·
1,723 Posts
I'm showing 24043955 for GM OE and 24256861 for ACDelco Gold which also crosses over to Cardone 736861F and Dorman 609201, both remans.

You can get them on Ebay, programmed to your VIN. To me they are surprisingly expensive. Used is $2500, new $4800+.

One did show up at GMPartsGiant for under $400 but you ought to call and make sure it is in stock. Use the 24043955 part number and of course, verify with your VIN.
 

· Registered
Joined
·
14 Posts
Discussion Starter · #5 ·
Thanks for the replies. Yes it is a 6 speed coupled to a Duramax Diesel. I need to make some decisions and probably pull the truck from the dealership. I bought the truck because the engine and transmission were supposed to be so good. Crap, another towing fee and an expensive obsolete computer.
 

· TOTM
Joined
·
1,723 Posts
Keep us posted if you don't mind.
 
  • Like
Reactions: Bigredwing

· Registered
Joined
·
14 Posts
Discussion Starter · #7 ·
Update: I checked in at Lexington Park Chevrolet and my truck is still sitting back on death row. They have security so I am not too concerned at this point. I also verified they are looking for part number 24043955 which from all I can find here an elsewhere is that it is obsolete. But, the replacement part number of 24256861 might be available IF they have used that number in their search. That I do not know. I would think that their nationwide search engine would show the alternate part number but I can't verify that. Next week I will check back in with them and find out. I also saw on GMPartsOnline the next higher assembly is the Control Valve Body which includes the TCU if I ready the description correctly. That part number is 24275872 and about $850 plus a core fee. I am going to check on that too. A bit more money but atleast I can get back on the road again. Fingers crossed.
 

· Supr Moderator AutoTech SS-Guru Mbr Extraordinaire
2015 High Country Duramax
Joined
·
19,428 Posts
The valve body does NOT incorporate the TCM.

The TCM on all the duramax trucks is mounted to the fan shroud in the front drivers side of the truck. It is a totally separate module.
 

· TOTM
Joined
·
1,723 Posts
If you don't hear back from them Monday, send me a PM with the last eight of your VIN and I'll ask my guy check.
 

· Supr Moderator AutoTech SS-Guru Mbr Extraordinaire
2015 High Country Duramax
Joined
·
19,428 Posts
Every single duramax ever made has had the tcm in the exact same location. So since 2001 it's always been driver's side fan shroud under the hood.

It's not just the duramax though. Every single Allison 1000 and 2000 series (larger ones too) have external TCMs.
 

· TOTM
Joined
·
1,723 Posts
The 2500/3500 gassers have 6L90 transmissions where the computer is inside the transmission (24275872).

The Allison 1000s have an external computer current listed as GM OE 24043955 and ACDelco Gold/Professional as 24256861.
 

· SilveradoSierra Guru
2004 Sierra 3500 6.0L, auto, extended cab, cab&chassis, upgraded to 4wd
Joined
·
3,118 Posts
It's not really "conflicting", as swathdriver was referring to a non-Allison transmission (the 6l90). You said you have the Allison, so it's not in the transmission.

Edit: the transmission will vary with what engine you have in your '09, most likely you have the Duramax if you have a Allison, if it had a gas engine, it would likely have the 6l90 (or at least, not the Allison, IDK what specific trans was used for the gas engines for that year).
 

· Registered
Joined
·
14 Posts
Discussion Starter · #15 ·
Anybody with a 2009 Silverado HD2500 equipped with a Duramax Diesel and Allison 6 speed transmission have a picture they can post of the engine bay showing the location of the TCM? Thanks.
 

· Registered
Joined
·
14 Posts
Discussion Starter · #17 ·
Thank you. I actually just found that video and wish I had found it many moons ago. Now I just need to locate the part, but armed with a better part number maybe I'll have some success. Really appreciate all the input on this issue and hope everybody has a great week.
 

· Registered
Joined
·
14 Posts
Discussion Starter · #19 · (Edited)
All I want for Christmas is a TCM. Still can't find any in the supply chain. So how long do I wait (not getting any younger myself) and what suggestions does anybody have? I hate to just dump the truck as good as it is otherwise. That would be a tremendous waste.
 
1 - 20 of 25 Posts
Top