I just had a shop do a LS swap with transmission n my 86 GMC K1500. The first shop said the engine and transmission was from a 2007 Silverado. They also told me it was a 5.3 with a 4L60. When they did not finish the work I took the truck to another shop. This shop said that the engine was not a 5.3 but a 6.0. The shop also believes that the 4L60 is actually a 4L80. The problem I am having now is the transmission will jump from 1st to 3rd or 4th and not down shift. My neighbor ran a scan on the computer and two codes cam back for the transmission, P0740 and P0785. Both codes are for a 4L60. How do I verify the transmission and if it is a 4L80 will flashing the computer again and have it reconfigured for the correct transmission. Is there a chance that if it was configured to the wrong transmission it would cause the shifting problem and reflashing and reconfiguring could solve saids problem?

 

I swear I am losing my mind today...

Anyway, on a 2007 engine, the VIN from the original will be etched into the deck surface at the rear of the cylinder block on the driver side.




Post the VIN and I will look-up exactly which engine it is.

As far as the engine displacement goes... it will be etched or cast into the front of the cylinder block.
Some times one the driver side, some times on the passenger side.

The photo below, shows a 6.2L cast into the block on the passenger side (left side of photo).

 

The 4L60E and 4L80E transmissions do not look a like. See photo below.

Left side = 60E Right side = 80E




Here is an image of what the transmission oil pans shape look like from below.




Lastly; you may have a problem with the transmission internal wiring harness. The PCM or external wiring can also be the problem.

 

So I got under the truck and counted the bolts, 17, so it is a 4L80e. Now is there a way to get to the VIN with the engine in the truck? I will go back out and see what I can find. Thank you for the information on what and where to look for. Does anyone know fi those codes come up because it is flashed for the 4L60 or do they come up even if it is the correct flash? Lastly, if I need the reflash, about how much should that cost if I do not have a VIN? Again thank you for the information and hopefully I can get it running correctly.

 

What PCM are you running? It's possible you can do a Segment Swap with HP Tuners & not need reflash.

 

Welcome back clinebarger

 

Always good to have cline around!

 

It is the stock PCM. What do I need for a laptop and how much is the HP Tuner software?

 

MPVI2 with 2 credits.....$398.99 https://www.summitracing.com/parts/hpt-m02-000-02

HPtuners isn't very picky, At least it wasn't when the original MPVI were being sold, Windows 10 is a safe bet! I have a Windows 10 HP laptop for logging & roadside changes & a Windows 10 HP Desktop for bench tuning & initial tuning at the shop.

 

I just bought a new tuning laptop for my car on sale for $249. 4gb ram(slot for 4gb chip add on already installed), SSD, windows 10 pro, I5 processor. plenty of computer and durable enough for personal tuning. Might be worth it for OP to check if they are still on sale.

-dalton

 

Any progress on this?

Last you posted; it sounded like you have a 4L80E being used with a PCM for a 4L60E and did NOT have a segment swap done.
Those DTCs are commonly seen before the segment swap is done.
Did you have the segment swap performed?

Those two DTCs are for solenoid circuits that do not exist in the 4L80Es control systems.
They are for the 3-2 Control solenoid circuit and for the TCC Apply solenoid circuit.

P0785 for example (For most 4L60E units but NOT all)...
The 3-2 Control solenoid circuit is a 2 wire circuit. Constant positive voltage and switched/ controlled ground (negative voltage).
The PCM is looking for a specific range of voltage over a specific range of time (8.00 to 18.00 volts. No lower or higher for more than 5.00 seconds).
This circuit does not exist in the 4L80E transmission...
So the PCM will see less than 8.00 volts for more than 5.00 seconds (0.00 volts constantly) and will set the DTC for the circuit.

Also in the future; for trouble-shooting the NO 2nd gear condition on a 4L80E transmission... disconnect the transmission main electrical connector from the drivers side of the transmission case.
The default would be second gear ONLY as both shift solenoids are OFF for second gear during normal operation.

For the 4L60E, instead of 2nd gear... 3rd gear would operate when the electrical connector is disconnected.

When "LIMP" mode is current for this Power-Train... 2nd gear and reverse are the only ranges that are usable.
As long as the transmission is functioning hydraulically and mechanically... 2nd gear would work, when disconnecting the electrical connector.

Good luck and give us some updates as things progress.

 

I have been trying to post a picture of the read screen for HP Tuners, it shows 2000 Chevy Tahoe 1500, 5.3L, 8cyl, GM_P01
P01 ECM, GM Gen3 V8, 4.3L V6
OS: 9381344

Also When I look at the shift chart 2nd Apply is at 255 across the board and 2nd release is at 237 across the board. Does that mean that the truck is in limp mode?

Thank you for all of the replies and for helping me out.

 

The ECM controls the shifting right? Is the 255 across the board maybe something to do with pressure applied? Need to see that picture!

 

So I gave up trying to find the VIN for the engine. I did find out that it is a Gen III 6.0, so it is either a LQ4 or LQ9. I downloaded a flash that has the correct engine, transmission, and OS. I did a complete swap with all sections. I tried to start the truck but VATS was enabled. I disabled it and the truck started no problem. I took the truck for a small drive and it shifted nicely, but it did not go out of second gear. I did a scan as I was driving it around, but I am still too new at this to know what I am looking for. I did look at all of the errors being thrown and I did not see the same two errors from before. I also have a file that says it has good shift points for a 4L80e. I will do a segment swap of the transmission portion and hopefully that fixes things, if not then it may be something mechanical that is wrong? Sorry about the span in posts. Thank you for the help, and if requested I can post the scan of the small drive.

 

Where did you end up with this? Sounds like you made some progress at least. You think you've got the right code in it now right? Shifts nicely but only 1-2 right? Can you manually shift it higher? What errors are being thrown now? You sound like you solved at least some of them but what's left? Did you get this resolved? Would love to know what was wrong!

 

There were no error codes for the transmission. The previous error codes were gone. All the codes for the engine are EGR codes. Also I cannot manually shift out of gears. It is stuck in limp mode right now.

 

This would indicate that the PCM still sees a 4L60E connected and not a 4L80E.
I am assuming that you have still NOT done a segment swap.

 

I actually did do a segment swap. I verified the OS and found someone that had good shift points for a 4L80. Once I did the swap it was in Limp Mode, but even with the other flash for the transmission that I had (supposedly for a 4L80) it still was not shifting correctly. The truck is currently at a transmission shop waiting to have the transmission pulled and torn apart. Here is where I really had the knowledge and garage to do the work.

 

Also could this mean that the transmission controller could be bad or even wiring has a problem?

 

Yes indeed; the PCM and/ or the harness could cause issues.