Will a 2004 lb7 tcm work on a 2005 LLY swap if I have them vin matched?. Thinking the tcm for the LLY might be toast it’s giving all kinds of codes
Help!! LB7 TCM work on LLY?
- Thread starter Bradgrantham59
- Start date
Yes, a LB7 programmed TCM will work on a LLY. Running a 2001 LB7 OS with a LLY is actually fairly common.
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Awesome thank you I’m taking it to the dealership to have everything vin matched so programming shouldn’t be a issue at least I think that’s why it cranks but won’t start
I'm 99% sure that the VIN in the TCM doesn't matter to the LLY ECM or BCM and a mismatch shouldn't cause a crank no start. If memory serves, way back when I first got EFI Live, I ordered a TCM that came out if a truck with an 8.1, and I plugged it into my truck and took it for a spin only to find that the shift points were totally wonky. That's when I figured out it had an 8.1 cal in it and once I flashed my original calibration into it, everything was back to normal.
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Ok cool. I still need to match the LLY ecm to my bcm I believe tho it’s a swap motor fires with starting fluid(I know I shouldn’t) but wanted to make sure and I have a u0105 code with no bad wires and all good power and grounds
If you can start it with starting fluid, but not by just cranking it, that is a mechanical problem that needs addressed. Usually something is preventing rail pressure from building at cranking RPM, such as a weak/worn CP3, failing injectors, restricted fuel supply, air getting in fuel supply, etc. A scan tool will be needed to watch rail pressure while cranking to verify that is what is happening.
Ah I was thinking the u0105 ( no communication with ficm) was causing it. I don’t have a expensive scanner but I’ll see if mine does have that option thank you
I think that Cougar281 is saying that if the TCM 5 speed is from a LB7 duramax and you are installing in a LLY duramax it should work ok. You don't not need to vin match it. The imbedded vin is more for the part number of the flash. The only experience I have was on a LBZ and that worked just fine with out programing.
Now if you want to spend the money to get a vin number matched to your VIN I bet someone will be happy to do that for you.
Now if you want to spend the money to get a vin number matched to your VIN I bet someone will be happy to do that for you.
See, if you'd post information like this to start, we'd be further ahead in helping you along. Is it an active code or in the history?
If the ECM is NOT communicating with the FICM, it should do as you described. You stated it will start with ether, but does it stay running?
Sorry it’s a history code I swapped the tcm like you said and the trans codes went away but not I’m still getting the u0105 and no start unless spraying starter fluid pulled a return line to check for fuel flow and there’s flow for sure I also use a gas lift pump btw
It needs to communicate with the FICM to run. Check your main connectors for the engine and FICM.
In your first post, you said LLY swap. Is this a Lb7 to LLY conversion or a total engine transplant into a different vehicle?
In your first post, you said LLY swap. Is this a Lb7 to LLY conversion or a total engine transplant into a different vehicle?
It’s a lb7 to LLY swap full engine under hood harnesses ecm ficm and tcm all swapped into my 04 lb7. I checked all the rub spots for messed up wires and no luck also checked the power and ground at the ficm and it has both only thing I didn’t know how to check is signal