C4 for an AOD

[import convert]

wel i thought of putting a C4 in my merc in place of an AOD. i figureed a built 3 speed would be cool and maybe even put a manual reverse valve-body on it. i can get a rebuilt one form work for like 500-600 dollars over a rebuilt AOD for 1500.

any ideas on this?

its a thought right now but i will need to replace my tranny since mine is getting a lot of miles on it.

[DuceAnAHalf]

i have a built C4 with a reverse manual valve body. with a C4 you dont have lock-up in third, so your converter will slip making more heat

[p71towny]

Do you plan on racing???

[1987cp]

I've had good experiences so far with the rebuilt C4 I have. Of course, I've yet to actually operate it in the 3.08 geared car it's in right now. I shall endeavour to keep you posted!

[import convert]

i have a built C4 with a reverse manual valve body. with a C4 you dont have lock-up in third, so your converter will slip making more heat

well id deffinitely have a tranny cooler or 2 if i did this. for those of you that have a C4, does your car feel quicker with it over an AOD?

i had a 89 lebaron with a 3 speed and it nevef seem to run out of tourque. it had hte 2.5L turbo motor and was always right near full boost at cruising speed. i did like that fact though.

[p71towny]

I think rear gears would make you happy instead of a tranny swap. Duce has a race car. I mean he can drive it on the street, but why give up O/D just to give up O/D.

[import convert]

well my AOD has over 200,000 on it andsince im building my motor up and will be over 250hp i figure i should get ideas on what to run for a tranny.

i work with a kid tha thad one in his mustang back in the day and hed run like 2500rpms at 80 so its not like im loosing rpms or gas milage ill just have longer gears and maybe a lower top end. (not like i need to go 140 in a panther)

i think itd be cool to have and different as well. ive heard theyre easier to rebuild too then an AOD and id rahter do the work myself and save the money while gettting the expierence.

personal prefference i guess

[p71towny]

Well then go for it!!

[gadget73]

so do up the AOD. I know of people sporting 200k mile trannys with engines that make that kind of power. I've actually driven the car myself, and just last year it went to Florida from PA.

[Lincolnmania]

yea my aod has 201,000 miles on it......shift kit and modded ho at 172,000
every c4 car i ever had the tranny shit the bed.......aod's are in the fmx family......i've never had an fmx go bad.....if you must have a 3 speed auto, the fmx is the ticket.....get some help installing cause the case is cast iron hehe

[Mercracer]

i work with a kid tha thad one in his mustang back in the day and hed run like 2500rpms at 80 so its not like im loosing rpms or gas milage ill just have longer gears and maybe a lower top end. (not like i need to go 140 in a panther)

i think itd be cool to have and different as well. ive heard theyre easier to rebuild too then an AOD and id rahter do the work myself and save the money while gettting the expierence.

With your stock gear, you are definitely loosing mileage because of running higher RPMs with a C4.
2500 RPMs at 80MPH with a C4 and a 225/70-15 tire would take a ~2.50 rear gear ratio depending on converter..... If you are running a 60 or 65 series 225 you would need even a smaller numeric ratio..
That car would be one slow pig from a stop.......

Ther is no doubt that a C4 is cheaper, but a good AOD is plenty tough and the OD sure is nice. I am running a bone stock 130,000 mile Mustang AOD with a Lentech valve body and TCS converter behind a Explorer motor with a TFS Stage 1 cam and a 175 shot of Nitrous in my Capri with no issues.... I run 4.10 gears. Like I said.. the OD is nice to have...

[import convert]

so if i was to do this id need like a 2400 stall converter? or yea i beef up my AOD, idk i got time to think about it.

ive heard AODs are a pain to rebuild, is that true?

[1987cp]

I think Ed was just talking about a cruise RPM assuming no converter slippage. I think you were looking at a 2400rpm stall or so anyway, weren't you? One thing to remember with the C4 is that a looser converter will mean higher observed RPM at cruise speeds since there's no lockup feature like our AODs have in Third and Overdrive. There was a tranny called the C5 that's basically a C4 with a lockup converter, but I don't think they're taken seriously for performance use - in fact, I'm pretty sure a typical buildup on a C5 involves basically converting it into a C4.

One advantage to building an AOD, at least as a GMN member, is that several folks here know quite a bit about the things and have built wide-ratio units, etc.

lincolnmania, where would a person go for a built FMX? I've definitely heard of them, but the only Ford 3-speeds I usually hear about are just the C4 ad C6. How does the FMX compare to the C6 in terms of strength, weight, and mechanical efficiency? I'm told a stock C6 is often good to about 600hp.

[Mercracer]

... where would a person go for a built FMX? I've definitely heard of them, but the only Ford 3-speeds I usually hear about are just the C4 ad C6. How does the FMX compare to the C6 in terms of strength, weight, and mechanical efficiency? I'm told a stock C6 is often good to about 600hp.

You are kind of srewed with the FMX. It is a heavy trasmission due to its cast iron case and there is really no performance aftermarket support for them. They make a great dependable grocery getter tranny though... The efficiency is lower than a performance C6. A "stock" C6 is not good for 600HP.. 600HP is nothing for a built C6 though.... 600HP is nothing for a built AOD. OD has a 400HP limit though... The lockup converter however can handle more than 800HP with upgraded components..... It is like running a 4th gear when you lock up the converter manually in 3rd and you eliminate the slippage in a loose converter....

[Mercracer]

I think Ed was just talking about a cruise RPM assuming no converter slippage. .

I was talking a tight converter with some slippage.... The numbers change with a standard transmission or a lockup converter....