Questions on 4L85E and Duramax combo
Apr 10, 2023 | 09:04 PM
#11
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Joined: Sep 2013
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From: Georgetown, TX
I only have 1 problem with the argument that it should be fine behind a 700 ft-lb Diesel, and that is the fact that they detuned the engine to exactly 460 ft-lb. Why tune it specifically to 460 if the trans is fine, why not an even 500 or 600? both of those would also provide less heat, wear, and tear for extended commercial use.
Lol, I would feel a lot more comfortable if 1 of 2 blown big block guys said "yeah, its fine".....
Lol, I would feel a lot more comfortable if 1 of 2 blown big block guys said "yeah, its fine".....
Apr 10, 2023 | 09:29 PM
#12
The problem with the Diesel is that it makes the torque so low. That being said, there is a few guys that use the Turbo 400 for racing behind the Diesel.
I have no idea what's different in the supermatic version of the 4L80E Vs the standard production 4L80E used in the cab in chassis as Gm doesn't really publish what they put in it.
I have no idea what's different in the supermatic version of the 4L80E Vs the standard production 4L80E used in the cab in chassis as Gm doesn't really publish what they put in it.
Apr 10, 2023 | 09:30 PM
#13
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I have certainly posted this on and searched several diesel forums, but 99% of the people on there have trucks, which pretty much all came with the Allison Trans, so no one knows specifics about the internals of the GM trans, lol. I am stuck in a catch 22....
Apr 10, 2023 | 09:35 PM
#14
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Anyone have experience with this shift kit? Seems like the smartest thing I can do short of having my transmission beefed up...
https://www.summitracing.com/parts/t...RoCuOMQAvD_BwE
https://www.summitracing.com/parts/t...RoCuOMQAvD_BwE
Apr 10, 2023 | 09:36 PM
#15
The only one who may know the differences is a guy on LS1 Tech in the transmission section. Apparently he is a retired GM Transmission engineer or something along those lines.
Apr 10, 2023 | 09:39 PM
#16
Anyone have experience with this shift kit? Seems like the smartest thing I can do short of having my transmission beefed up...
https://www.summitracing.com/parts/t...RoCuOMQAvD_BwE
https://www.summitracing.com/parts/t...RoCuOMQAvD_BwE
Try the LS1 Tech side in the transmission side. We have some stuff on this side but not many people doing it these days as we once had.
Apr 10, 2023 | 09:50 PM
#17
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Joined: Apr 2023
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I am already traversing the internet on an epic quest for knowledge, sounds like searching for the mystic guru of LS1 Tech will have to be the next path I take.. I thank this village for hosting me while I rest and helping me in my journey....
Apr 10, 2023 | 09:53 PM
#18
LOL.
Here is one of the threads with some tech in it that I remember
https://www.performancetrucks.net/fo...t-drum-506779/
Here is one of the threads with some tech in it that I remember
https://www.performancetrucks.net/fo...t-drum-506779/
Apr 10, 2023 | 10:26 PM
#19
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Here is one of the threads with some tech in it that I remember
https://www.performancetrucks.net/fo...t-drum-506779/
https://www.performancetrucks.net/fo...t-drum-506779/
On the one hand I stopped working on cars so I could afford to pay others to fix mine, but then my gut says to find a junkyard core and stop being a wuss about it. I could find Trans shop to install HD2 shift kit and rock that till Trans dies, then build one, but I hate driving a rig waiting for it to die, heartburn. Starting to think I will take it easy on the tuning for first 2 years and make it in to a good camper, then build a junkyard trans. It just bugs me knowing software is the only thing standing between me and another 200ft-lb and 100hp
Apr 11, 2023 | 07:15 AM
#20
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Joined: Dec 2012
Posts: 310
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From: Iowa
Oh, I understand that the standard 4l85E is not much different than the 4L80e. That is not what I am asking about at all.
1: I am trying to understand why the 4l85E has a torque rating of 46o ft-lb VS the "Supertronic 4l85E" with a torque rating of 685 ft-lb. Because GM needed to market the new supertronic/supermatic to go with their crate engines. It's nothing more than a VB recalibration and an extra friction in the direct. The valve body recalibration I don't have details on, but you can make easy changes to the stock valve body on any 4l8x series trans and achieve the same or better results.
2: I am trying to learn how to tell a regular 4l85E from a Supertronic 4l85E. Find a reciept from GM showing you or someone else bought a "supermatic" unit. There won't be external differences unless GM has started sending them with special tags.
3: I am also trying to learn if a regular 4l85e can be upgraded to the stronger Supertronic variant with upgraded clutches etc, or if it is a different beast entirely. It can be easily upgraded to the same or better.
I understand these questions can probably only be answered by someone who has rebuilt multiple variations of the 4L8Xe, hoping this is the right place for one of those people to be hanging out. I guess my 100's of 4l8xe's, parts design, valve body manufacture, etc doesn't count as enough background on these.
I understand that the 4L8Xe series can be built to handle quite a bit of power, but I do not want to blow up my transmission in the first place if I can avoid it. I have seen posts of people who tune up their Duramax van, then blow the 4L85e because it can not handle full engine power. If I have the Supertronic, I can tune the engine now. If not, I should not buy a software tuner until after I have a transmission that can handle it.
1: I am trying to understand why the 4l85E has a torque rating of 46o ft-lb VS the "Supertronic 4l85E" with a torque rating of 685 ft-lb. Because GM needed to market the new supertronic/supermatic to go with their crate engines. It's nothing more than a VB recalibration and an extra friction in the direct. The valve body recalibration I don't have details on, but you can make easy changes to the stock valve body on any 4l8x series trans and achieve the same or better results.
2: I am trying to learn how to tell a regular 4l85E from a Supertronic 4l85E. Find a reciept from GM showing you or someone else bought a "supermatic" unit. There won't be external differences unless GM has started sending them with special tags.
3: I am also trying to learn if a regular 4l85e can be upgraded to the stronger Supertronic variant with upgraded clutches etc, or if it is a different beast entirely. It can be easily upgraded to the same or better.
I understand these questions can probably only be answered by someone who has rebuilt multiple variations of the 4L8Xe, hoping this is the right place for one of those people to be hanging out. I guess my 100's of 4l8xe's, parts design, valve body manufacture, etc doesn't count as enough background on these.
I understand that the 4L8Xe series can be built to handle quite a bit of power, but I do not want to blow up my transmission in the first place if I can avoid it. I have seen posts of people who tune up their Duramax van, then blow the 4L85e because it can not handle full engine power. If I have the Supertronic, I can tune the engine now. If not, I should not buy a software tuner until after I have a transmission that can handle it.
You can find a stock 4l85e and have it rebuilt at any number of reputable shops and it'll live just fine...better than the "supermatic" crate trans you buy.
If this is a budget build, then simply dual-feed the direct clutch and use a simple VB recalibration kit and you'll increase your tq capacity from that 460 or whatever number you've been quoting.
If this is something you plan on adding larger injectors, or better turbo, etc then the list of upgrades you should look into will be more than the "supermatic" anyway.
