2013 Z71 Suburban additional transmission cooler

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Trey Hardy

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What's the benefit of bleeding air and pre-filling the cooler?

The fluid drains back to the pan when the engine is shut off. That is one reason why the level is checked while running and up to temp.

Cooler input/output orientation doesn't really matter. Mounted up just leaves fluid in the cooler when engine is shut off.

Air gets into lines every time engine shuts off, and gets pushed out as soon as engine starts and fluid fills the lines. Trans has a vent on top.
Probably no benefit to be honest I’ve seen people mount these sideways upside down right side up it don’t matter it’s all personal preference it’s not like having to bleed air out your radiator or anything but I did it anyways for ***** and giggles
 

BG1988

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ok - I responded to his post as he quoted the OP, telling him to pull the trans thermostat...The OP has a '13 Z71 Burban conventional gasser w/a 6L80 so wanted to let him know (just as i recently learned on this forum) that the conventional GMT900s didn't come w/the CBVs...

That out of the way, I keep thinking about your offer to send me that 2ML70 Hybrid trans...Been wanting to do one but no yard or core supplier around here has seen one in ages, lol...Perhaps we can talk off line if you get to the point you're seriously thinking about sending one to me to overhaul.
we don't know the build date it could have a revised 6L80E transmission with the thermostat
 

Knagawa350

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Hey all! I just bought a 09 Tahoe hybrid, dude I bought it from passed along a sweet 2ML70 with two clutches failing. Where can I find a manual on this transmission to rebuild it? Dealership doesn’t want to waste time doing it, they would rather install a refurbished one for 6k. I’ve already sourced parts and GM confirmed part numbers for me. Every shop here in Portland Oregon told me to kick rocks as soon as I asked them to swap or rebuild. I really like this rig, it’s my first Chevy also so already starting to get a bad taste in my mouth. Any info really helps thanks all!
 

Doubeleive

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Hey all! I just bought a 09 Tahoe hybrid, dude I bought it from passed along a sweet 2ML70 with two clutches failing. Where can I find a manual on this transmission to rebuild it? Dealership doesn’t want to waste time doing it, they would rather install a refurbished one for 6k. I’ve already sourced parts and GM confirmed part numbers for me. Every shop here in Portland Oregon told me to kick rocks as soon as I asked them to swap or rebuild. I really like this rig, it’s my first Chevy also so already starting to get a bad taste in my mouth. Any info really helps thanks all!
start poking around the web
 

Knagawa350

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I’ve seen this, everything I found on the internet says disconnect the hybrid and 12v batteries and then go to work. The clutch packs I need I found already when all the shops said they can’t. I was just hoping to find the order in which the plates are aligned. Otherwise it’s gonna be take it apart and label and match everything. I’m renting shop time from a local place that does that.
 

j91z28d1

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I’ve seen this, everything I found on the internet says disconnect the hybrid and 12v batteries and then go to work. The clutch packs I need I found already when all the shops said they can’t. I was just hoping to find the order in which the plates are aligned. Otherwise it’s gonna be take it apart and label and match everything. I’m renting shop time from a local place that does that.


I believe I found a book on it once searching around a year or so ago. I'll look and see if I can find it again..

if you do rebuild it, if you can start a thread about it and take some pics along the way. it could be useful for some other people. at this point a used tranny is about the best case for most people.

but use, remove the 12v battery cable first, and then the hybrid safety plug. unbolt the high voltage wires running to the tranny, they should be orange and it should remove about the same as any other tranny. from there.. you're brave haha. have you rebuild autos before? there's a tranny guy on here that shown some interest, but he's in Las Vegas and can't find any used cores to open up.
 

j91z28d1

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you've probably seen it, but I believe this is what I was thinking of. there's a 3 part article. but not much on rebuild guild




there's also this, the aux pump on the first few years had some issues and can throw a code for slipping when it's just a lack of pressure. Just in case this might be yours.


gm has an updated module if I remember right for it on older than 2010 or 2011 years.
 
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Knagawa350

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I believe I found a book on it once searching around a year or so ago. I'll look and see if I can find it again..

if you do rebuild it, if you can start a thread about it and take some pics along the way. it could be useful for some other people. at this point a used tranny is about the best case for most people.

but use, remove the 12v battery cable first, and then the hybrid safety plug. unbolt the high voltage wires running to the tranny, they should be orange and it should remove about the same as any other tranny. from there.. you're brave haha. have you rebuild autos before? there's a tranny guy on here that shown some interest, but he's in Las Vegas and can't find any used cores to open up.
I’ve done a civic transmission but by no means anything hybrid. But also haven’t taken any of my vehicles to a shop in over 10 years including motorcycles, I usually get it done on my own. The Tahoe only has 145k on the dash so I’m not ready to let it die. I did however find an online instruction manual that you have to pay a monthly membership for that appears to be the GM literature with diagrams, and all the specs. It even has all the warnings and what sequence to do the work in. Highly specific instructions that I will be following slowly and to the t. It says disconnect the hybrid battery and give it 5-10 minutes to lose the pre charge, during that time disconnect the 12v. It seems like a highly sensitive system due to the high voltage through the fluid, but nothing has to be reprogrammed unless a sensor is replaced. Luckily it has the instructions for relearning/reprogramming if there are issues. I got railed on this but I’m not a quitter. I’ll take pictures for sure, no way I’m the only person ever to have this problem. An old article said GM sent a notice to get the computer reprogrammed for the 1-3 clutch housing to provide less pressure because they realized it was causing damage when the clutch was applied. Gonna see if I can get it reprogrammed still when I get it running, even if I have to pay. Anyways starting on Thursday either way, parts are showing up Tuesday and Wednesday from a surplus dealer that only carries OEM parts from GM. Wish me luck
 
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Knagawa350

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you've probably seen it, but I believe this is what I was thinking of. there's a 3 part article. but not much on rebuild guild




there's also this, the aux pump on the first few years had some issues and can throw a code for slipping when it's just a lack of pressure. Just in case this might be yours.


gm has an updated module if I remember right for it on older than 2010 or 2011 years.
Read this article twice along with another magazine that had similar info, I finally found an online manual that is 2ML70 specific for overhauling the entire unit and how not to die in the process
 

Knagawa350

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you've probably seen it, but I believe this is what I was thinking of. there's a 3 part article. but not much on rebuild guild




there's also this, the aux pump on the first few years had some issues and can throw a code for slipping when it's just a lack of pressure. Just in case this might be yours.


gm has an updated module if I remember right for it on older than 2010 or 2011 years.
I can tell it’s actually slipping since it does it when on the freeway when only the regular pump is running and not the auxiliary running. When in full electric it has no notices loss of power
 

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