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2004 Military Humvee / 5.3 Ls swap pushing a 4L80e. Truck runs great now but having issues with transmission, I did my own harness and purchased HPtuner. I stayed with the 4L80 but dumped the 6.5 for the swap, originally harness and pcm/ecu was for 5.3 / 4L60 but did a segment swap for 4L80 but still keep going into lock up and stalls when I stop ( no Codes ) and or it shifts from first to second and third quick and bogs down, when using HP and shift manually seems to have no problem and a lot of power. I'm new to the forums and HPtuners but have done a few swaps just with giving my money to some one else to program and not share what or how to do. any advise or even harsh constructive criticism is greatly appreciated.
Yes, I used LT1 swap for the diagram. I think may have the program wrong for the transmission. I couldn't find an os 9381344 with a 5.3 and a 4L80 to do a segment swap so I tried line by line. I have sense found one and will try a segment swap later. thank you for the response, I will follow back up
Yes, I used LT1 swap for the diagram. I think may have the program wrong for the transmission. I couldn't find an os 9381344 with a 5.3 and a 4L80 to do a segment swap so I tried line by line. I have sense found one and will try a segment swap later. thank you for the response, I will follow back up
Upload your tune file here. I have a OS9381344 4L80E tune file.
04 Humvee 5.3 implant and harness twisting original 4L80
This is my current tune file; engine runs great and has a lot more power than expected as long as I shift manually and disable the lock up (37" tires don't even have a chance LOL) of course front drive line is not installed yet (full time AWD) needing a OS 9381344 to do a segment swap for 5.3/ 4L80
thanks
This is my current tune file; engine runs great and has a lot more power than expected as long as I shift manually and disable the lock up (37" tires don't even have a chance LOL) of course front drive line is not installed yet (full time AWD) needing a OS 9381344 to do a segment swap for 5.3/ 4L80
thanks
1st. it appears that your swap file is correct now. Use the original file and then open the other as a compare file. When viewing the compare file all the differences are highlighted green instead of the blue. I am double checking on this. I'm waiting on a senior tuner to look at it too.
2nd Full time AWD has to have the front drive shaft hooked up to transfer power correctly. I think the have 2 VSS's The VSS's read at the AWD unit. When the 2 VSS signals don't agree. I had trouble with a 2005/6 Hummer AWD bench unit. The customer didn't put in the front axles, then claimed it didn't shift right. I don't remember the details, but I do remember driving 60 miles round trip just to find out that the full drive train needed hooked up.
Didn't know those came with 2.73 gear's...
Here is the file I used to create a segment swap file of my own. I'm not going to use that file, but wanted to see how they look when done properly. I used it for the other two that were posting about the P0742 & P0785 code they had.
These Military Humvee (HMMWV, high mobility multi wheeled vehicle) with the 4L80 only have one speed sensors in the front side of the transmission that only for input shaft speed and the rear is plugged. When I did the re-pin and added the second sensor and connector which is now the VSS for the ECM the transfer case has a mechanical dive cable to the old school speedometer on the dash as far as the gears not too sure how to figure the gear ratio the diffs are 2.73 and then you have a portal gear box on each wheel which is 1.92:1 does that make it 4.65 ratio.
These Military Humvee (HMMWV, high mobility multi wheeled vehicle) with the 4L80 only have one speed sensors in the front side of the transmission that only for input shaft speed and the rear is plugged. When I did the re-pin and added the second sensor and connector which is now the VSS for the ECM the transfer case has a mechanical dive cable to the old school speedometer on the dash as far as the gears not too sure how to figure the gear ratio the diffs are 2.73 and then you have a portal gear box on each wheel which is 1.92:1 does that make it 4.65 ratio.
Got ya!!! I'm very unfamiliar with the Military vehicles. I am familiar with the 4L80E in general.
4L80E's use a ISS (input speed sensor) & an OSS (output speed sensor) They both emit a frequency signal that gets converted by the PCM
The ISS is used to monitor input shaft speed. This signal should have RPM readings in Park & Neutral and "0" in Reverse and Drive. They also use it to get a better reading on TCC slip speed.
The OSS is for the final drive output speed. On 2wd it is used as the rear sensor in the transmission case. 4x4 usually have a plug in the rear of the case and they actually don't have the reluctor wheel on the rear planet. 4x4's OSS signal is gotten from the TFC or AWD unit. It is usually in the tail-housing of that TFC/AWD unit. Most GM trucks use 3 TFC sensors. You should physically check for the rear sensor to have tone ring or reluctor wheel in the transmission!!!
So what you are saying that the vehicle has a AWD unit with no OSS signal? .
It also has 2.73 differentials & individual wheel gear boxes of 1.92:1??? (2.73 x 1.92 = 5.24 final drive.) Is the tires on this larger or smaller than OE? is the AWD unit a 1.1:1 or say a 1.8:1 ratio? What's the model #? Both of these change overall wheel speed.
My theory is now that you are giving it a signal with a 2.73 (that's what is in the tune file) and it needs to see a 5.24.1 ratio. How to calculate this or configure your tune file from here, I'm not sure of. You may be better off in the Diagnotics & tuning section with a post. More people will see it and be able to help. I'll look for it so I can learn & respond as research it.
Last edited by Tranzman; 11-28-2022 at 12:31 AM.
Reason: Add a ??
Thank you Tranzman,
I used the tune file you sent me to do the segment swap and ever thing is working great, I even am able to switch the performance mode on and off (tow haul) Thank you again, I am very pleased with the performance using the 5.3 and the 4L80. Next step is learning some tunes and turbos.
I'm wanting to do the same thing with my HMMWV. I got the 6.5 out, and need to know what to buy to make the LS 5.3 out of a 06 chevy truck talk to the 4L80e transmission in the HMMWV. Very new at doing this
I'm wanting to do the same thing with my HMMWV. I got the 6.5 out, and need to know what to buy to make the LS 5.3 out of a 06 chevy truck talk to the 4L80e transmission in the HMMWV. Very new at doing this
I would skip all the bull crap and just go straight to a Holley terminator setup for your configuration.
I'm more of a hands on, do it yourself guy, and I'm not familiar with holly so I used the harness from the doner truck and reworked it myself, LT1wiring .com has all the pin outs to do it. as far as the motor mount you can use the 6.5 rubber mounts and blocks and Ls motor mount adapter plates, and she fits like a glove however you will need to get a flex plate and spacer kit to couple the 5.3 to a 4L80e. Most importantly if you like to tinker than it will be worth it and you will learn a lot along the way. Decisions decisions!?! do you stay with dual voltage (12,24 volt) or change everything out. I bought a 24-volt alternator from DC power that bolts right in place of the GM alternator and am staying with dual voltage for simplicity. None the less you're in the right place, these guys are great and full of info but also have a little tough skin along the way.
[QUOTE=50lstrk;20469901]This is my current tune file; engine runs great and has a lot more power than expected as long as I shift manually and disable the lock up (37" tires don't even have a chance LOL) of course front drive line is not installed yet (full time AWD) needing a OS 9381344 to do a segment swap for 5.3/ 4L80
thanks[/QUOTE
Im doing the exact same thing with my humvee, however I do not have the experience with these swaps as this my first one. Can you tell all you needed to do to make your project work…like is there an adapter we need for the trans, new harnesses, reprogramming etc?
thanks for any help
Got ya!!! I'm very unfamiliar with the Military vehicles. I am familiar with the 4L80E in general.
4L80E's use a ISS (input speed sensor) & an OSS (output speed sensor) They both emit a frequency signal that gets converted by the PCM
The ISS is used to monitor input shaft speed. This signal should have RPM readings in Park & Neutral and "0" in Reverse and Drive. They also use it to get a better reading on TCC slip speed.
The OSS is for the final drive output speed. On 2wd it is used as the rear sensor in the transmission case. 4x4 usually have a plug in the rear of the case and they actually don't have the reluctor wheel on the rear planet. 4x4's OSS signal is gotten from the TFC or AWD unit. It is usually in the tail-housing of that TFC/AWD unit. Most GM trucks use 3 TFC sensors. You should physically check for the rear sensor to have tone ring or reluctor wheel in the transmission!!!
So what you are saying that the vehicle has a AWD unit with no OSS signal? .
It also has 2.73 differentials & individual wheel gear boxes of 1.92:1??? (2.73 x 1.92 = 5.24 final drive.) Is the tires on this larger or smaller than OE? is the AWD unit a 1.1:1 or say a 1.8:1 ratio? What's the model #? Both of these change overall wheel speed.
My theory is now that you are giving it a signal with a 2.73 (that's what is in the tune file) and it needs to see a 5.24.1 ratio. How to calculate this or configure your tune file from here, I'm not sure of. You may be better off in the Diagnotics & tuning section with a post. More people will see it and be able to help. I'll look for it so I can learn & respond as research it.
Tranzman, I see that you able to help with this humvee issue that I too am facing. I don’t have a way to program my ECU/PCM and was wondering if you do them and if so for how much?
Thanks
2004 Military Humvee / 5.3 Ls swap pushing a 4L80e. Truck runs great now but having issues with transmission, I did my own harness and purchased HPtuner. I stayed with the 4L80 but dumped the 6.5 for the swap, originally harness and pcm/ecu was for 5.3 / 4L60 but did a segment swap for 4L80 but still keep going into lock up and stalls when I stop ( no Codes ) and or it shifts from first to second and third quick and bogs down, when using HP and shift manually seems to have no problem and a lot of power. I'm new to the forums and HPtuners but have done a few swaps just with giving my money to some one else to program and not share what or how to do. any advise or even harsh constructive criticism is greatly appreciated.
Guys. Not sure if any one knows but im giving this a shot..I ha e a 95 AMG Hummer. Originally came with a 350 SBC. I'm currently doing a 6.2 lsa swap and im havi g trouble with clearance for the oil filter between the front drive shaft. Any suggestions would be helpful. Thanks in advance.
11-24-2022, 10:56 PM
Humvee Ls 5.3 swap with 4L80e 
