6L80/90e's How they work

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Originally Posted by XLR8NSS

I ordered a copy of the transmission(6L90E) manual and a set of service manuals for my truck('07 GMC 2500HD) from the link above. They should be here on Monday, can't wait to take a look. :)

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Did you recieve your trans manual? How much detail does it contain on the actual operation of the gearbox? Or is it more about dissasembly/repair?

The 6L80 Hydra-Matic Technician Guide covers the complete theory-of-operation.

The ATSG 6L80 "TechTran" manual covers the complete disassembly/overhaul/repair with some theory (but not as much as the HMTG).

$120 for shipping and $25 for handling for a $35 book! :shock:

gmh308 did you end up finding one cheaper?

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Originally Posted by carneb

$120 for shipping and $25 for handling for a $35 book! :shock:

gmh308 did you end up finding one cheaper?

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Only via a mate over there. Have been too busy to organise so far. :doh2:

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Originally Posted by carneb

Did you recieve your trans manual? How much detail does it contain on the actual operation of the gearbox? Or is it more about dissasembly/repair?

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Yep, I got it a while back. It shows the complete hydraulic circuits for each gear and much more. I have to go now but, will post back later.

Can anyone with one of these manuals answer the following question for me:

What are the ramifications of spinning the torque converter of a 6L80e at idle speeds with no electrical power applied to the transmission? Range selector in P. Will damage be done after extended periods of doing this?

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Originally Posted by PSWired

Can anyone with one of these manuals answer the following question for me:

What are the ramifications of spinning the torque converter of a 6L80e at idle speeds with no electrical power applied to the transmission? Range selector in P. Will damage be done after extended periods of doing this?

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Unclear how much damage if any will occur, but certainly the trans with no power on it does produce an unusual noise.

If the GM ECM fault action is to go into immediate engine off mode if TCM comms lost, probably a good chance it is not a good thing ("Immediate Landing"?). If it will continue to drive in limp mode in 3rd gear, then cant be too bad if not extended period ("Soft Landing"?)

The GM service manual does go into a discussion on the various fault modes, but dont have one at hand at present.

You could try www.repairprocedures.com for the manual info.

:cheers:

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Originally Posted by gmh308

Unclear how much damage if any will occur, but certainly the trans with no power on it does produce an unusual noise.

If the GM ECM fault action is to go into immediate engine off mode if TCM comms lost, probably a good chance it is not a good thing ("Immediate Landing"?). If it will continue to drive in limp mode in 3rd gear, then cant be too bad if not extended period ("Soft Landing"?)

The GM service manual does go into a discussion on the various fault modes, but dont have one at hand at present.

You could try www.repairprocedures.com for the manual info.

:cheers:

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Thanks. I did notice the weird noise. I have the service manual and the fault action for power loss on the transmission IGN circuit (which is what I'm concerned with) is max line pressure among other things. Not engine shutoff.

I'm asking because the Transmission ignition circuit is not powered up during remote start in my application, and I need to know if I'll damage the trans if I leave it this way.

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Originally Posted by PSWired

Thanks. I did notice the weird noise. I have the service manual and the fault action for power loss on the transmission IGN circuit (which is what I'm concerned with) is max line pressure among other things. Not engine shutoff.

I'm asking because the Transmission ignition circuit is not powered up during remote start in my application, and I need to know if I'll damage the trans if I leave it this way.

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Ok. Just read your moniker. 5.3L with 6L80, so a conversion. Sounds odd that no start/run power for remote start (oversight on conversion harness?). Would imagine GM normally runs start/run power to the trans for remote start in factory cars.

:cheers:

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Originally Posted by gmh308

Ok. Just read your moniker. 5.3L with 6L80, so a conversion. Sounds odd that no start/run power for remote start (oversight on conversion harness?). Would imagine GM normally runs start/run power to the trans for remote start in factory cars.

:cheers:

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Yes, it was an oversight on my part. There was no conversion harness, the bus I put the new fuse for the transmission on was an ACC bus and not an IGN bus. The wiring is hard to access now that the instrument panel is back in place, so I wanted to make sure this is absolutely necessary before I go back in and re-do it.