Transmission jerk on downshift 3nd to 2nd low Speed no pedal gas

[JBaker4981]

Attached. Acceleration 2-3 upshift. Full Power.https://cloud.tapatalk.com/s/664f5552...224-WA0022.mp4

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I would not drive the car as briskly as that while diagnosing this - The car downshifted 3-2 for most of your video and then 2-3 at the very end.

I would be interested to see how she accelerates in 3rd without hitting WOT (Wide Open Throttle) and making it down shift. I have a feeling that you are going to be slipping in 3rd at lower speeds or other behaviors may appear.

[alexdmc1]

I would not drive the car as briskly as that while diagnosing this - The car downshifted 3-2 for most of your video and then 2-3 at the very end.

I would be interested to see how she accelerates in 3rd without hitting WOT (Wide Open Throttle) and making it down shift. I have a feeling that you are going to be slipping in 3rd at lower speeds or other behaviors may appear.

Hi JBaker. I just returned from a long tour. when cold it drives well, when hot the problems begin.....if I drove at full throttle in third gear no problems, no slipping. I also replaced the ATF dexron 3 oil to be safe but the problem was not resolved. I notice that when I release the accelerator, in third gear the revs (rpm) are low? it's like it doesn't have enough pressure to tighten the clutches....I don't know. what do you say?https://cloud.tapatalk.com/s/6651f52b...525-WA0022.mp4

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[Ron]

Maybe I'm not following all this correctly but:

I notice that when I release the accelerator, in third gear the revs (rpm) are low?

Are you sure that isn't where you are in 2nd gear (accelerating) and when you let off it shifts up to 3rd (which would drop the RPM, i.e., normal)?

it's like it doesn't have enough pressure to tighten the clutches...

If the clutches aren't tight the engine would rev up a lot.

[alexdmc1]

Maybe I'm not following all this correctly but:

Are you sure that isn't where you are in 2nd gear (accelerating) and when you let off it shifts up to 3rd (which would drop the RPM, i.e., normal)?


If the clutches aren't tight the engine would rev up a lot.

Hi Ron. How are you. you're right: during acceleration the car shifts from second to third and obviously the engine rpm drops. like every other car does. the problem is when I'm in third gear at low speed without accelerating (foot raised) instead of downshifting you hear jerking..... but when cold for the first 20 km everything works perfectly.

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[Ron]

Hi Ron. How are you. you're right: during acceleration the car shifts from second to third and obviously the engine rpm drops. like every other car does. the problem is when I'm in third gear at low speed without accelerating (foot raised) instead of downshifting you hear jerking..... but when cold for the first 20 km everything works perfectly.

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I see... My first guess would be the GC, new or not considering your other tests results. Put test lights on it if you haven't yet...

[alexdmc1]

I see... My first guess would be the GC, new or not considering your other tests results. Put test lights on it if you haven't yet...

Hi Ron. I just did the test with the lights. At first everything works perfectly. the lights come on and the automatic transmission shifts correctly. when it warms up and in third gear at low speed I don't press the accelerator pedal, the car remains in third gear, the lamps are both off and the problems begin..... thanks for your help

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[Bitsyncmaster]

Hi Ron. I just did the test with the lights. At first everything works perfectly. the lights come on and the automatic transmission shifts correctly. when it warms up and in third gear at low speed I don't press the accelerator pedal, the car remains in third gear, the lamps are both off and the problems begin..... thanks for your help

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This does really sound like the electronics are failing in high temps. It's to consistent to be a marginal connection.

[David T]

Hi Ron. I just did the test with the lights. At first everything works perfectly. the lights come on and the automatic transmission shifts correctly. when it warms up and in third gear at low speed I don't press the accelerator pedal, the car remains in third gear, the lamps are both off and the problems begin..... thanks for your help

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Go back to my post #5. You have bad solder joints on the circuit board. You just have to open it up to get to the circuit board and reflow some solder on each joint. Between the vibration and the temperature a cold solder joint can cause this, very typical. It is possible to do this without taking the whole thing off. You remove the cover, pull the circuit board out enough to get to the backside and with a soldering iron (a small pencil iron, you don't need a big gun) you reheat each joint and add a SMALL amount of fresh solder. Be careful not to add too much solder or make any solder "bridges" to other circuits on the board. On some of the shift computers you do have to remove the coating, use a small steel brush.

[Michael]

Go back to my post #5. You have bad solder joints on the circuit board. You just have to open it up to get to the circuit board and reflow some solder on each joint. Between the vibration and the temperature a cold solder joint can cause this, very typical. It is possible to do this without taking the whole thing off. You remove the cover, pull the circuit board out enough to get to the backside and with a soldering iron (a small pencil iron, you don't need a big gun) you reheat each joint and add a SMALL amount of fresh solder. Be careful not to add too much solder or make any solder "bridges" to other circuits on the board. On some of the shift computers you do have to remove the coating, use a small steel brush.

He is using Ed's governor which I believe is a new solid state design like DMCH sells.

dsc08364.jpg

[alexdmc1]

He is using Ed's governor which I believe is a new solid state design like DMCH sells.

dsc08364.jpg

This Is my replacement unit. IMG_20240527_081500.jpg

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