AODs "neutralling out" in cold

[kishy]

Of my 3 AOD cars, two have been winter driven. Both of those two have exhibited a tendency to "fall out of gear" when decelerating to a stop. The car will freely roll backwards when this happens, engine will rev, but once the rev has been done it kicks back into gear and goes fine. I'd call it a firm engagement, not a slip.

Generally if this happens at all, it will only happen once or twice per drive cycle, and only at the first/second stops of the drive. It has happened identically in my '91 and my '84.

Both cars have had fluid and filter changes in my ownership of them, both cars have different brand fluids but still Dex/Merc. There has not been a fluid level issue at the times these issues happen.

Is this just a sticky valve possibly, due to cold parts needing to expand more with heat to fit better?

The '84 does something extra, which I believe indicates worn direct clutches: until it warms up, engagement to 3 has shift flare. It otherwise won't slip once engaged. Also before it warms up, 4 does a weird slip-bump sensation, kind of like two shifts in one. Both of those issues apply only to the '84, and they both go away once it warms up a bit.

[VicCrownVic]

The trans in The Ice Car will do that, but I need to check the fluid level and it's due for sevice. Last time it was serviced was when I put it in this car 45-50k miles ago (3rd car this trans has been in since my dad had it rebuilt for his long gone '89 MGM about 150k miles ago).

I've just been letting it warm up for long enough to get almost up to operating temp (about 5 minutes for mine) and that's been enough to keep it happy. I just have a factory dummy temp gauge, I should install a real gauge so I know what temps the thing is running.

[cvbox1990]

On the 91 have u checked the TV (throttle valve ) cable for breaks,proper adjustment?not 100% sure if the 84 will have a cable or rod,but that one sounds more like what u said a stiking valve and/or bad valve body seals,worn governor internally in the transmission.I have had my share of transmission issues on my 1990 put a FEW different transmissions in it due to various issues,finally got the damn thing lined out and on my way home I gunned it and it dropped to first then nuetral,juice the gas a little and it would engage,what happened was my tv cable broke where the plastic end connects to the throttle body. Just food for thought try dropping the pan on the 84 change fluid/filter and run a couple quarts of either Lucas or trans x,might buy u some time,hope this helps.

[kishy]

Well, the 91 hasn't done it in 2 years...because I haven't drove it in the winter this or last winter. But it was doing the exact same thing when I last drove it in below-freezing temperatures. TV adjustments are "to spec or higher", not below, and linkages are connected reliably.

Just kinda reminded me that I had meant to look into it (e.g. post about it) when the 84 did the same thing.

[DerekTheGreat]

Like Vic said, be sure to check the fluid level when cold too. Below a certain point there's just not enough juice in there. My '85 did it too, but that was due to the TV rod not being adjusted correctly and also missing the grommet. I replaced the grommet, fiddled with the TV rod and dodged a bullet as it never did it again. I also changed the filter and replaced the fluid that was lost in the process. Other thing to do is just wait for it to build a little heat if all else fails. Not sure if this is recommended but if you're in a hurry you could put in gear and hold the brake for a few minutes like you are at a stoplight.

[ssme]

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[kishy]

Like Vic said, be sure to check the fluid level when cold too. Below a certain point there's just not enough juice in there. My '85 did it too, but that was due to the TV rod not being adjusted correctly and also missing the grommet. I replaced the grommet, fiddled with the TV rod and dodged a bullet as it never did it again. I also changed the filter and replaced the fluid that was lost in the process. Other thing to do is just wait for it to build a little heat if all else fails. Not sure if this is recommended but if you're in a hurry you could put in gear and hold the brake for a few minutes like you are at a stoplight.

Definitely no fluid level issue. If that were it, it would happen way more often. For example it didn't happen this morning at all but the temperature is similar to the last few days.

TV pressure is high (I put it that way) and it shows in the shift points. I've never put a gauge on it but the shifts are in good spots so I feel pretty confident in that end of things. Grommet is in good shape.

Post your question here for an expert answer......................they know transmission problems inside out and can help you rebuild or offer you performance upgrade..........http://www.clickclickracing.com/foru...ck-Click-Tech& or http://www.network54.com/Forum/260730

I'll check it out, thanks.

[TecNickal]

Friend had this happening on his 88. He couldn't remember when it was last serviced. He did a complete trans service and it quit neutralling out when COLD at a stop. My old 91 Colony Park did this too.

[kishy]

Friend had this happening on his 88. He couldn't remember when it was last serviced. He did a complete trans service and it quit neutralling out when COLD at a stop. My old 91 Colony Park did this too.

'Complete trans service' done approximately 2000km ago. Wix filter and Valvoline Dex/Merc. Pan and torque converter drained.

[DerekTheGreat]

Definitely no fluid level issue. If that were it, it would happen way more often. For example it didn't happen this morning at all but the temperature is similar to the last few days.

TV pressure is high (I put it that way) and it shows in the shift points. I've never put a gauge on it but the shifts are in good spots so I feel pretty confident in that end of things. Grommet is in good shape.



I'll check it out, thanks.

You sure? I thought the same of my car and when I checked it, low. You have any leaks? I didn't have my trans adjusted for firm shifts, just went for what felt right. It's not a corvette

[HiFiMerc]

I'd throw a gauge on the TV port just to be sure. My old trans shifted ok, but the TV pressure was way too low when checked with a gauge.

[gadget73]

could just be the seals shrink a bit in the cold and the pressure leaks internally until things soften up. I don't remember either of mine doing this, but I haven't driven the Towncar in snow in years and the Mark VII is so horrible in snow that its not even worth the attempt.

[kishy]

Fluid is identical to how it came out of the bottle, and exactly on the full mark where I filled it to before (running, still cold, after cycling through all shifter positions).

Even if the TV pressure is low, it can't be increased. It'll never shift if I increase it, it already holds first and second nice and long compared to my other AODs. It's either high or the trans is shot, no two ways about it. The adjustment screw is halfway to max as it is and I increased it to that point largely just to feel better about assuming how it was set. Closed throttle coasting won't engage overdrive until around 65kmh-ish which is way higher than the other two (and trans shop says zero throttle OD engagement should be way lower).

It also downshifts very aggressively and readily, which is another high TV pressure indicator...

[VicCrownVic]

could just be the seals shrink a bit in the cold and the pressure leaks internally until things soften up. I don't remember either of mine doing this, but I haven't driven the Towncar in snow in years and the Mark VII is so horrible in snow that its not even worth the attempt.

Makes sense in my case. Trans was rebuilt 10 1/2 years 150k miles ago.

blkpnthr, do you know the history of your trans, mileage and such?

[sly]

This could also be a pump seal issue in the trans. AOD "morning sickness" basically means it won't work until it heats up a bit and the pump seals enough to provide enough pressure to put things in gear. If it's got a trans cooler on it, you may need to bypass it in the colder months as it will aid in "freezing" it and not letting it come up to temp.

Or something has come loose inside and it's bleeding pressure somewhere.