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Discussion Starter · #1 ·
I can only drive backward! No forward gears.

2007 9-3 v6 Aisin AF40 (TF80-SC) 160k
YOUTUBE 1
YOUTUBE 2 : scraping and intermittent rattle oy when brake held down in reverse.

SYMPTOMS
- In drive, the D is shown on the dash but the car just revs. Higher RPM does nothing.. No movement or sound except for the engine. Same is true of the tiptronic.

- In reverse it works just fine, backing up my steep driveway no problem. But if I hold down the break there is a scraping sound and intermittent rattle.

- There are no OBD II codes. Strange! Is it possible there are codes on the TCM I can't see? (Any folks with a Tech 2 near NH/VT?

WHAT I TRIED
- I tried flushing the ATF by taking off the intercooler hoses and filled it at temperature with Ford XT-8-QAW using the proper drip test and an IR gun. Fluid looked dark but I wouldn't say it is a milkshake
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- I plan on taking off the pan and inspecting the solenoids and valve body.

- From the WIS, it appears that there is a separate clutch and solenoid for reverse. So perhaps a passage in the valve body is blocked. I could try manually exciting the linear solenoid for drive C1
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WIS

HISTORY
- When I purchased the car a year ago it had intermittent shiting flares, where the car would rev freely in between shifts, then catch and jolt you forward.

This was remedied for several months by doing a drain and fill. Then last week it started slipping again. Then after stopping on the off-ramp on a highway where it was doing fine, it no longer could go forward.

If there is a definite "you blew a X. Get a new tranny." Let me know so I don't waste my time. Or if there is a trick to diagnosing these besides taking off the valve body i could use some help. Unless the codes are hidden its really strange no errors are thrown. I thought the car monitored solenoid current and shift speeds. And surely a bad TCM would throw a code. I've used my OBDII plenty of times on this car before.

Thanks for your help. I hope I don't have to scrap this car!

Lebanon.NH
 

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the intercooler has nothing to do with the AT..the intercooler is to cool the compressed air(turbo) before it enter the cylinders..
 

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Discussion Starter · #4 · (Edited)
I've taken the transmission cover off (I'll write it up later), and tested SL1 by measuring 6ohms (which is correct) and quickly pulsing current from a bench supply under a current limit. I was hoping it would show a failure to give me confidence to buy a solenoid replacement kit. I'll probably do that anyway, as they are low cost. If anyone suspects a linear solenoid, pulsing 12V to these linear solenoids is a quick way to see if one is stuck. They take a 300Hz PWM signal at 0-1000mA, but they actuate fine under a 12V pulse. Just don't do it for a long time or a lot in a row as they are not meant for continuous current. This can be done from disconnecting the TCM connector without touching the transmission.

But now I am thinking that it could be the manual control valve, which is connected to the Park, Reverse, Drive, Manual gear selector. It redirects pressure from the sump to reverse or drive passageways and is moved by the shift lever. The shift lever is not sticking and the indicator on the dash reads the correct gear, but perhaps it is not pushing the spool far enough. Or there could be a leak somewehere.

- Explanation of Manual Valve

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What I should have done is buy a Tech2 to diagnose further. If anyone has looked at the auto transmission with a Tech2 I would be very interested in a screen shot of what it would show.

Getting to the solenoids on a 6spd TF-80SC AF40 is tough work - more difficult than what the 5spd appears to be. It requires taking off several coolant hoses and plenty of other parts. The transmission pan bolts are shallow and awkward to reach. And the last gotcha is that the solenoids are held in with a pin that is removed with a magnet, not a bracket like the 5spd. Don't ask how many hours it took me to find that out.
 
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