6T40 transmission problems

gigimarfa

Newbie
Joined
Jun 30, 2023
Messages
4
Points
1
Make
Opel/Vauxhall
Model
Astra J
Year
2011
Miles
87000
Engine
1.6l petrol / A16XER
Hello, I have the following car:
-Opel/Vauxhall Astra J - 1.6L Petrol -
-engine: A16XER/85kw/115hp
-transmission: 6T40-MH8 GEN. 3
-vin: W0LPD6ED1BG008280
The car refuses to move forward, only goes back in reverse smooth, only feel a small, small, bunk in the seat when I shift through gears. When in D, the front of the car rise a little but little bit barely noticeable but won't go forward.

I have gone to a junkyard and I've found the exactly same car as mine as described before:
-Opel/Vauxhall Astra J - 1.6L Petrol -
-engine: A16XER/85kw/115hp
-vin: W0LPC5DD3DG096590
!! but this has an 6T30-MH9 GEN. 3 transmission on it.
-Do you think it will work plug and play on my car as it is the same car that I've got it from? Junkyard guy has no knowledge about it.

From what I've search on google they share the same TEHCM (as it's GENERATION3 written on the back of the trans). Should I first try to clean the valve body and solenoids on mine? My transmission has no error codes at all, scanned with 3 tools. From what I get if I put the 6T30 on my car it may need programming.
-Wondering if I may put the 6T30 up on the car with the TEHCM from mine (6T40). I have dropped 5L of oil at cold temp from my trans, it has a coffe look and it stains the paper hard. What y'all advise me to do. ?
 

billr

wrench
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Do you want a guess? Continue looking for a 6T40. It seems like the 6T30 has slightly different gear ratios, and is designed/built for less power. The different gear ratios may set codes, affect emissions or power or fuel economy and may even disable cruise-control. And, of course, the less-rugged 6T30 may fail even sooner than a 6T40
 

grcauto

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May 29, 2014
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What does the scan tool show for the shift solenoids when in D?
BTW You are scanning the TCM correct?
 

gigimarfa

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What does the scan tool show for the shift solenoids when in D?
BTW You are scanning the TCM correct?
No error codes, All solenoids are ON when in D... which I saw on the web is not ok. But why aren't any codes there
Scanned with launch, maxisys and a poor delphi. All of them show no codes.
 

billr

wrench
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Let's back up a step here. What is the trans doing wrong when driving? You said the fluid looks sad, needs a fluid/filter change at least; but no indication of actual trouble symptoms. I'm ignoring the solenoids all "on" for now... don't know if that is true of not.

If the trans does have severe operational problems. like car won't move either forward or reverse, then disconnect the electrical cable to the valve body (VB) and see what difference that makes.

Next steps would be to check hydraulic line-pressure and solenoid resistances. Then, remove VB and do air-checks on the internal clutches/seals.

Are you interested in repairing this trans, or pretty much focused on just replacing it?
 

gigimarfa

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Let's back up a step here. What is the trans doing wrong when driving? You said the fluid looks sad, needs a fluid/filter change at least; but no indication of actual trouble symptoms. I'm ignoring the solenoids all "on" for now... don't know if that is true of not.

If the trans does have severe operational problems. like car won't move either forward or reverse, then disconnect the electrical cable to the valve body (VB) and see what difference that makes.

Next steps would be to check hydraulic line-pressure and solenoid resistances. Then, remove VB and do air-checks on the internal clutches/seals.

Are you interested in repairing this trans, or pretty much focused on just replacing it?
would be easier if you'd read the whole post. Car won't move forward, only reverse. When I shift thru PRND it bunks a little in the seat. No codes. Scanned for codes, nothing. Realtime checks - all solenoids on when in D. Speed sensors are working. Reverse is working like a charm.

Before that It had no symptoms, just one day D went away. Fluid is dark brown just like coffe, no metal shavings in it - as far as I can see.
I'm gonna remove the TCM and the valve body to clean and inspect them, if that won't make a difference I will just swap the trans with the T30 Gen3 one which --!! I got from the same car as mine !!--

My concern was if the T30 gen3 will fit my car if it's not the same model even tho it's from the same car/engine.
Some said it will fit but needs programming, some said will fit but won't last cause it's inferior to T40, and some said it won't work at all.

i was thinking if I can just replace the TCM from my T40 to the T30 as they both share the same valve body and solenoids to avoid programming - in case it is needed.
 

billr

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OK, I missed (or forgot) that you lost all F gears; but the rest of my advice still applies.

I think it is likely the T30 will attach to the engine OK, GM has been pretty good about keeping the trans/flywheel config consistent across engine families and years.
 

gigimarfa

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OK, I missed (or forgot) that you lost all F gears; but the rest of my advice still applies.

I think it is likely the T30 will attach to the engine OK, GM has been pretty good about keeping the trans/flywheel config consistent across engine families and years.
I was talking to some transmission shop owner from ohio and he said it is going to work to bolt t30 on my car but it will need programming and for that I may just swap the TCM from mine. He also advised me to start by cleaning my Valve body. So that's what I'm gonna do. Seems internals for these two won't match up, just the valve body and if that's not the issue Imma just swap them over
 

bp042665

transmission guy
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Nov 26, 2012
Messages
809
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Location
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if you could get the tcm from the 6T30 Car you should be good only problem is when you go to program it off your vin# it will program a 6T40 trans not the 6T30
 
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