The AOD on my '59 is going in Tuesday, 2/4/03. Are there any "heads up" I should know about regarding calibrating the speedometer with the AOD?

One other question:

Will I need the kickdown linkage that I have on there now? It's a Lokar kickdown that goes from my 302 to the C4 tranny? Or, will I need a new Lokar kickdown?

Thanks gang!!!!! As always, I really appreciate your help...

Daryl

 

Does the AOD have a mechanical speedometer gear in it? The way I understand speedometers is a standard set rpm for a certin mph. You could take the speedo out of your 59 and put it in a 85 mustang and it will work and be accurate. You would need to calibrate it with the gears in the transmission or get a ratio adapter.

 

'57 Ford,

I'm not sure if the speedo gear in the AOD is mechanical or not. It just got done being built last Thursday afternoon. The guys who are doing the install, though professionals, suggested I take the truck to a local (well, it's 50 miles north, but around here, that's local!!!) speedo shop to have it calibrated professionally. Think I'd be wise to take their advice.

Thanks for the feedback,
Daryl

 

I would do the same. It will be rite. I wish their was one around here.

 

Daryl,

If the AOD has a mechanical speedometer with a nylon gear in it, you can calibrate the speedometer yourself. All you have to do is determine how many miles per hour you are off using the present gear and which way. If the speedometer reads too high you need a speedometer gear with more teeth and if it reads too low you need a gear with fewer teeth. Each tooth is worth about 5 mph. Count the number of teeth on the gear you have and go from there. I've used this method quite successfully in several street rods...

 

OK, Daryl, I thought that we'd worked this out when you were first contemplating the switch to an AOD, but I still don't think you've quite got a grasp on this yet. I just want to make sure you know what you're dealing with here so that you'll be informed and satisfied with your new transmission. I think that the AOD swap is a pretty good move. You will definitely make the engine happy with the lower cruise RPM's. I'm still not sure that you will realize enough of a fuel mileage gain in the end to justify the replacement cost of a perfectly good transmission, but there is no doubt that it will help with the fuel bill and it will make your engine last longer.

What concerns me here is that you're still asking about the kickdown. There is no kickdown on an AOD. There never was or will be. All the other 3 speed trannies had one, but never the AOD. The AOD, however, does have a throttle valve that is very similar in appearance and operation to a kickdown mechanism.

The big difference is in the function of the different systems. If the kickdown linkage on your C4 were far out of adjustment or even non-existent, the absolute worst that could happen is that it wouldn't downshift when you tromped the throttle. If the throttle valve linkage on an AOD is out of whack or not there, you will most certainly smoke your brand new transmission before you get out of town. The adjustment and proper operation is crucial as it regulates hydraulic line pressure in the transmission. It gives the valve body throttle feedback throughout the entire range of throttle motion and must constantly move in sync with the throttle and be adjusted for proper initial line pressure at throttle rest and full throttle. A kickdown on the three speeds never moves until your throttle enters the last 25% or so of it's range of motion. It's only mission in life is to drop you out of 3rd and back to 2nd when you floor it. Does that make any more sense?

As to your question about whether or not your cool Lokar kickdown will work on the AOD, in a word, no. It is installed and set up to only move at full throttle as described above instead of in constant unison with the throttle. However, all is not lost. Lokar does make a throttle valve linkage specifically for the AOD that will meet your needs exactly. Yeah, yeah, I know. More stuff to buy! I think they market it as a "kickdown" which really makes the hair stand up on the back of my neck, but it does function the way it needs to. Go check it out on there website. I would strongly discourage you from dropping the truck off for the new trans. to be installed without either taking the installer the new Lokar kit or at least discussing his intentions for connecting and adjsting the throttle valve. He may already have another idea. Whatever you do, don't let him tell ya that what you've got will work. If he thinks it will, it would be a red flag to me about his qualifications to be working on your transmission to begin with. Don't be afraid to grille him on this. An error may make you both very sorry. Mostly you because I'll bet he'll say it was your fault somehow when it burns up.

Good luck and let us know what you think of it when you get it put in. The AOD is a great transmission. It has just gotten a bad rap from guys that didn't understand the throttle valve. I don't want to see you be one of them!

 

Rage,
Thanks for the heads up info. I've printed it out and will take it with me Tuesday morning to discuss the points you made therein.

Regards,
Daryl