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6L80/90 Tech Thread

the_white_shadow said:
Im pretty low with those already 4.3 in the atlas and 5.83 in the diffs. I took it out last week and it was plenty low enough for the most part.
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You mentioned wanting the lower 1st, but not needing any of the higher gears. My point was that lowering your axles or tcase gets the same basic idea.
 
gt1guy said:
There's one thing I'm going to eventually try on my 6l90 and it's something I read an article about years ago that was done on a older turbo400 automatic. In the article they hooked up an accumulator to the pressure port on the case. Think Accusump.
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I'm finding out that the way the 80/90 works internally, an accumulator on the pressure port would actually create problems and not accomplish what I had hoped.
 
YotaAtieToo said:
I have yet to run one, but I'm a big believer in these.

It seems obvious, but some don't realize that a 6l80/90 with a stock 2.7 tcase will be lower than a th400 or 4l80e with a 4:1 tcase. Seems some guys who don't need a super crawl are happy with just running a 205.

I really want this trans in my rig, but would like to see more tech on adapting it to different engines and running a stand alone controller first.
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I am currently in the process of swapping a 6L90E/NP205 into my 76 Wagoneer behind a Mercedes Diesel OM606. I am using a "Piggy Back" controller since you cant take out the TCM inside the valvebody. Seems the only downfall is having to tune both transmission as well as the controller. I am using the TCM 2650 from Zero Gravity Performance (PCS). I have to say, there is a LOT to be had with the tunability of this controller. It has a ton of features. I am running 4.56 gears on 37s. I am really curious how it will work out on the low end as well as top end drivability.
 

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WaggyOM6 said:
I am currently in the process of swapping a 6L90E/NP205 into my 76 Wagoneer behind a Mercedes Diesel OM606. I am using a "Piggy Back" controller since you cant take out the TCM inside the valvebody. Seems the only downfall is having to tune both transmission as well as the controller. I am using the TCM 2650 from Zero Gravity Performance (PCS). I have to say, there is a LOT to be had with the tunability of this controller. It has a ton of features. I am running 4.56 gears on 37s. I am really curious how it will work out on the low end as well as top end drivability.
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Interesting

What are you using for adapter, flex plate, tc ect?
 
WaggyOM6 said:
I am using Doomsday Diesel adapter, mercedes flywheel, bolted to "simulated mercedes tq converter" (billet adapter), bolted to GM flexplate, and then GM tq converter. Its all GM drivetrain from there.
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Do they actually make a 6l80e adapter or is it a th400 adapter?
 
YotaAtieToo said:
Do they actually make a 6l80e adapter or is it a th400 adapter?
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It is a GM 90* adapter. The mercedes sits at a 15* angle. The adapter is for whichever 90* GM transmission you want. I had a TH400 previously, just felt more like a go fast buggy vs a crawler.
 
WaggyOM6 said:
It is a GM 90* adapter. The mercedes sits at a 15* angle. The adapter is for whichever 90* GM transmission you want. I had a TH400 previously, just felt more like a go fast buggy vs a crawler.
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Ok, I figured any 90* adapter would work with the 6L, but wasn't 100% sure.
 
YotaAtieToo said:
Ok, I figured any 90* adapter would work with the 6L, but wasn't 100% sure.
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Yessir, it all mates up pretty easily. The biggest change I did was refab my motor mounts to bring the drivetrain down and rearward just a couple inches from where I had it originally.
 
CDA 455 II said:
That's exactly what I'm enquiring about.

I know the 4L80 can be converted to full manual only/no electronics.
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Completely different modes of operation.
The 6L80/90s are clutch to clutch trannies and can't really be transformed into a manual setup.
 
CDA 455 II said:
It has to communicate/coordinate with the engine computer, correct?
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Not necessarily. You could have it communicate with another controller that isn't the engine ECU.

But it needs some sort of electronic input.
 
Its also a timing issue. For every shift your releasing one clutch and applying another at essentially the same time. If you release the first clutch and take too long to apply the second, that creates a shift flare. If you apply the second clutch too soon the shift is too harsh and can damage the trans. The computer controls all that and the factory stuff will supposedly learn and adapt its timing for smooth firm shifts.
 
Ghetto Fab. said:
Its also a timing issue. For every shift your releasing one clutch and applying another at essentially the same time. If you release the first clutch and take too long to apply the second, that creates a shift flare. If you apply the second clutch too soon the shift is too harsh and can damage the trans. The computer controls all that and the factory stuff will supposedly learn and adapt its timing for smooth firm shifts.
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Exactly.
 
Ghetto Fab. said:
Its also a timing issue. For every shift your releasing one clutch and applying another at essentially the same time. If you release the first clutch and take too long to apply the second, that creates a shift flare. If you apply the second clutch too soon the shift is too harsh and can damage the trans. The computer controls all that and the factory stuff will supposedly learn and adapt its timing for smooth firm shifts.
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So it's more complicated/more involved than an full-manual 4L80 set up, correct?
 
Hey Guys, Thought id jump in here. Myself and a buddy have been running the 6L80/90 in our ultra4 cars for the last 3-4 years. They have overall been awesome. Only failure has been not enough fluid.

I recently have been sponsored by Holley and am installing the Terminator Max with their new 6L80/90 controller. This links the 6L80/90 to their Terminator system. The biggest question I have, and not sure if anyone would know, is if this controller actually reflashes the tune on the TCM, or if it just alters the information being sent from the Terminator to the TCM.
 
CDA 455 II said:
So it's more complicated/more involved than an full-manual 4L80 set up, correct?
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As far as control, yes I would say so. You just can't remove the electronics out of it. There isn't any way to control the trans effectively without the electronics and some sort of computer.

Earlier 4spd electronic trans like the 4l60, 4l80, and AW4 are really just simple hydraulic auto transmissions that used solenoids to do what the governor and kickdown cable systems used to do. Its not hard to pull the solenoids out and control it manually. These new transmissions like the 6l80, 8l90, ZF8HP are a whole different breed of trans. There are some interesting possibilities with transmissions like these, but you have to be comfortable with computer systems.
 
Ghetto Fab. said:
As far as control, yes I would say so. You just can't remove the electronics out of it. There isn't any way to control the trans effectively without the electronics and some sort of computer.

Earlier 4spd electronic trans like the 4l60, 4l80, and AW4 are really just simple hydraulic auto transmissions that used solenoids to do what the governor and kickdown cable systems used to do. Its not hard to pull the solenoids out and control it manually. These new transmissions like the 6l80, 8l90, ZF8HP are a whole different breed of trans. There are some interesting possibilities with transmissions like these, but you have to be comfortable with computer systems.
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This. Shit like accumulators and whatnot get deleted because you don't need them when you can pulse the solenoid instead.
 
arse_sidewards said:
This. Shit like accumulators and whatnot get deleted because you don't need them when you can pulse the solenoid instead.
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Whats funny, is the trans itself actually seems simpler now. There isn't the plethora of accumulator pistons, springs, check balls, governor, etc... Heck they don't even have the band any more. Its all just clutch packs and planetaries now. Everything that was complex is now contained in the TCM.
 
Ghetto Fab. said:
Whats funny, is the trans itself actually seems simpler now. There isn't the plethora of accumulator pistons, springs, check balls, governor, etc... Heck they don't even have the band any more. Its all just clutch packs and planetaries now. Everything that was complex is now contained in the TCM.
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Same shit when I try to explain wiring a PDM vs fuses, relays and switches.
 
broken4_racing said:
Hey Guys, Thought id jump in here. Myself and a buddy have been running the 6L80/90 in our ultra4 cars for the last 3-4 years. They have overall been awesome. Only failure has been not enough fluid.
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That's good to hear. I'm sure they haven't been babied. Who's converters do you run?


Bebop said:
Did you read the instructions :
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Very interesting. Seems it could be tuned through HPTuners if the Holley thing isn't robust enough.
 
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