AOD to C4

[Smokestacklightnin]

Just curious if a C4 would be a direct replacement for the AOD. Is a stock C4 stronger than a stock AOD?

[1987cp]

Main headache is the shift linkage (IMO).

[1980c10]

I must ask but why? An aod is plenty strong for what you have or can be made plenty strong, and your gonna miss that OD if you ever get gears.

[1990LTD]

4.10s behind a C4 = 5100 revs to get to 100mph

[gadget73]

actually the ratios in a C4 are not that different than the AOD, just no overdrive obviously. Drive around in D and you'll have a pretty fair idea of what the motor is gonna do as far as rpm goes.

Strength is debatable. Personally I've always felt the stock C4 was a turd. I don't like how they shift, and I've seen enough of them cooked behind bone stock 302s to not be impressed. The AOD is arguably no better as far as shifting or durability goes though. They can be built to handle plenty of power for less money than an AOD though, and they are lighter and use less power so for a race application there are advantages. If you want to drive down the highway with one and 4.10 gears, you may find it sucks moosecock though. Its all about the goal and what you want to spend to get there. An AOD can handle anything a C4 will, it just costs more money to get it to the same point.

Linkage is an issue as mentioned, but if you go with a non-stock floor shifter, thats not a concern. I seem to recall you need to swap the flexplate but don't quote me on that. I'd almost guarantee clickclickracing will have an aod > c4 conversion guide that will answer all your questions though. Just be aware there are two different imbalance flexplates for the 302, pre-82 and post-82. Make sure whatever you pick (if it needs to be changed) matches the year of your motor.

[mrltd]

don't see why shift linkage is an issue, same pattern...same style lever, same type of connection to rod....

now, kickdown... that will be an issue. However it's not needed. Unlike the aod, the c4 won't die without it.

Not worth it though. I'd keep the AOD. A good one will be just as tough as a c4 and it's not as expensive as thought to build one that can handle abuse.

[1987cp]

don't see why shift linkage is an issue, same pattern...same style lever, same type of connection to rod....

I'll believe that when you come out here and show me how to reinstall my AOD linkage so that it, you know, hooks up and works. I even have two detent levers to choose from, one that works with the '79 linkage and one that doesn't.

[DuceAnAHalf]

cut the stock linkage off and use an aftermarket shifter (B&M, TCI, etc.).

and assuming your car is a 79-90 it is a bolt in, you just slide the tranny crossmember up a few inches and use the other set of holes on your frame. just make sure you get a big bell (164-tooth) C4 so you can re-use your stock flywheel and driveshaft.
also the C4 is about 40#s lighter.

but like someone else mentioned it sucks for highway use, no lockup and no OD, with my converter that stalls about 3k i turn about 3000 rpm to run 50mph with 3.55s and a 28" tire

[mrltd]

I'll believe that when you come out here and show me how to reinstall my AOD linkage so that it, you know, hooks up and works. I even have two detent levers to choose from, one that works with the '79 linkage and one that doesn't.

I am always right. And it sure will work.


I guess I'm remembering Mustang parts.

[Mercracer]

The AOD is arguably no better as far as shifting or durability goes though. .

The AOD is inherently stronger in gears 1-3 as it is based on the FMX. The problem is that OD becomes the weak point and will take down the tranny....

[gadget73]

yes the gears themselves are stronger, but the stock shift calibration and converters suck so they don't fare terribly well if you beat on them, though with a little work and at least a trans cooler they do OK. I like AODs, don't get me wrong. I wouldn't even use a C4 for wheel chock if I had my way about it, but in stock form they're just not that spectacular.

[1987cp]

I wouldn't even use a C4 for wheel chock if I had my way about it, but in stock form they're just not that spectacular.

I shall now send you my spare core to use as a wheel chock, and haunt you day in and day out till I see pictures proving that you've used it for its new purpose.

[Mercracer]

yes the gears themselves are stronger, but the stock shift calibration and converters suck so they don't fare terribly well if you beat on them, though with a little work and at least a trans cooler they do OK. .

You hit it on the head. A Lentech Valve Body, a good converter and cooler turns a factory slush box not suited for abuse (that is what pounding on a stock 4000lb+ car is) into an impressive tranny. My factory '91 Mustang LX tranny has seen low 11's in a 3200lb car. This summer it may see 13s or better in a 4000lb car.

[1980c10]

I like AOD's but like you guys said, in stock form they are the definition of sucking.

[gadget73]

personally I feel the stock C4 shifts even worse than an AOD, but thats just my 2 cents. I've been in a fair number of C4 cars that had no detectable second gear, they did a 1-N-3 shift sort of thing. Second gear worked under heavy throttle only and they were really really sloppy through the shifts.