My '85 MGM, "Maisa"

[matth825]

The instaclear cars had the 100 amp 1g alternator as standard. Non instaclear cars had either the 60 amp 1g or the 75 amp 2g depending on the year.

All three of those alternators have very weak idle output with the addition of the 2g being a fire hazard.


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[Arquemann]

I wouldn't consider the idle output of my 60A 1G terribly weak, it's not great, but passable.
With the stereo on, high beams dim only a little bit when idling. Though my alternator is a genuinely new unit.

[friskyfrankie]

The instaclear cars had the 100 amp 1g alternator as standard. Non instaclear cars had either the 60 amp 1g or the 75 amp 2g depending on the year.

All three of those alternators have very weak idle output with the addition of the 2g being a fire hazard.


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Fire hazard due to the wonderful connector (not the voltage regulator but the top power one). Probably designed to disintegrate before blowing the alternator, I would assume. Sort of like a fuse.

[gadget73]

Instaclear put out un-regulated voltage, not un-rectified. It was always DC, just at higher than normal voltage. There is no practical way to bypass the diodes in an alternator, but running full voltage to the field to juice the output voltage is very easy.

1G alternators don't have that stupid plug either. Thats a 2G thing. The 1G has a proper bolt-on connection. idle output is lousy, but its a pretty reliable alternator.

[Arquemann]

I've had too much time with my thoughts. I'm doubting everything again.

Could the jerking on decel be caused by the transmission?

From what I remember, u-joints were pretty good and the trans mount only has 100k miles on it. The trans shifts and downshifts nicely and doesn't really clunk when put into gear.

I really don't want to spend 600-700€ on a carb conversion to get shafted and have the same issue still. The jerky decel is the most annoying issue.
But atleast the carb will (hopefully) solve my rich running and terrible MPG issues.

[gadget73]

the transmission usually won't cause it directly, but since the torque converter is fully locked in 3 and 4 any engine running problems feel very obvious.

[Arquemann]

the transmission usually won't cause it directly, but since the torque converter is fully locked in 3 and 4 any engine running problems feel very obvious.

Is the converter always locked in 3 and OD? I was wondering if the lockup might be coming and going during decel, but it might be way more noticeable vs if it's just the engine bucking.
The jerking isn't harsh at all, but enough for me to notice and get annoyed by.

[friskyfrankie]

Is that not a "feature" of all AOD tranys? That old "kick in the pants" around 3rd and OD on AOD's from that period.

[Arquemann]

Is that not a "feature" of all AOD tranys? That old "kick in the pants" around 3rd and OD on AOD's from that period.

Surely Ford knew how to make a drivetrain that coasted smoothly? Like every single fucking year before the AOD?
If not, Imma sell the fucking car.

[friskyfrankie]

Surely Ford knew how to make a drivetrain that coasted smoothly? Like every single fucking year before the AOD?
If not, Imma sell the fucking car.

Agree completely but if we are talking about the same "noise/feeling" there is not much to do about it. On the later tranys, the only issue was using Mercon as opposed to Mercon 5 and sometimes a trany sensor to reduce or eliminate trany shudder. At least you could mitigate or eliminate that problem but the AOD's?? I know NO way around that lockup issue.

[Arquemann]

Agree completely but if we are talking about the same "noise/feeling" there is not much to do about it. On the later tranys, the only issue was using Mercon as opposed to Mercon 5 and sometimes a trany sensor to reduce or eliminate trany shudder. At least you could mitigate or eliminate that problem but the AOD's?? I know NO way around that lockup issue.

When I coast in this car, there's an intermittent "bump", feels like a misfire. It does seem to happen in all gears, but it isn't as pronounced in first or second, so it probably isn't a lockup issue.
No shudder or noise and except for the 1st gear whine, my trans is totally silent.

[friskyfrankie]

I know the later GM's/CV's (like mid 90's) have a trany whine but not sure about the AOD's. My friend has a '88 CV so I'll have to check it out when I can get my hands on the car. Doesn't sound like anything to be overly concerned about. As long as the fluid is up and clean with no other issues I'd just enjoy the ride.

[87GrandMarq]

All aod based transmissions have that 1st gear whirring noise, it’s totally normal.

Op you shouldn’t have bucking on decel, my 87 doesn’t. It did when I had the ground for all the sensors in the wrong spot. I know you’ve tested a lot of sensors but there could still be a wiring gremlin hiding somewhere.


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[sly]

3rd and 4th actually bypass the torque converter via the inner input shaft IIRC. This is what effectively gives the AOD complete lockup. It does not have a lockup torque converter in the sense of a lockup mechanism in the torque converter. Later AODe and 4r7x transmissions however do have a clutch pack in the torque converter that is used for lockup.

[gadget73]

right, its not a lockup in the modern sense. Everything before the AOD had no lockup, and everything after used a clutch. The AOD has a split input system. The torque converter drives 1 and 2, 3 and 4 are driven directly from the converter shell. Modern things tend to unlock the converter for decel, the AOD simply cannot do that. On the other hand its impossible to have converter shudder because there is no converter clutch to slip.

It doesn't mean they're guaranteed to hitch and buck though. None of mine do or have done that. I have driven things with misfires though and you can really tell when the engine is running poorly.