Who is an expert on the AOD trannys and wouldn't mind answering some diagnostic/troubleshooting questions?

 

Whats the question and I will give it my best guess.

 

I'm having some odd shifting. I just put a brand new rebuilt AOD in my 71 f100. Used a lokar tv cable with edelbrock carb.

The trans is up shifting kind of early, and downshifting way late.

1-2 shift is soft to normal, about 10-12 mph under light throttle
2-3 shift is strong, but early, about 22 under light throttle.
3-4 shift is pretty good under moderate acceleration, but under light throttle, it will shift hard at 40mph.

It doesn't want to downshift with throttle, at least not until I get into it hard. But it does downshift with throttle..
Downshifting when slowing down is my concern, it doesn't come out of OD until about 35mph, which gets the engine chugging pretty hard at only 7-800rpm. Then if I try to speed back up it doesn't downshift unless I really get into it, (which on my carbed motor means it's dropping vacuum and loosing all the torque) so it makes it that much harder.

Basically, I want it to hold gears longer before up shifting, and downshift sooner.

I'm thinking I need the geometry corrector bracket for the edelbrock to hook up to the AOD. And to better tune the tv pressure.

I set the cable up so that at idle, there is NO slack at all on the tv valve, and maybe even slight pressure. (I know this isn't the "proper" setting, but it's better than having too low of pressure, so I errored on the high side.)

 

It would seem that the TV pressure is still low, keep adjusting it out to get later shifts, this will also help with the forced and coasting downshifts. The carb geometry may be a issue, you will just have to play around with it.

You may end up having to put a gauge on it to make sure the TV pressure is where it needs to be.

 

I have full throttle set to full pressure. It still does it. I think it must be the geometry of the carb arm.

 

Mark Kovalski is our ford trans guru.
Ford Truck Enthusiasts Forums - View Profile: Mark Kovalsky
if Mark can not figure it out, it can not be fixed.

 

Mark knows much less about the AOD than jk080 does. I've never worked on that transmission.

 

I installed the geometry corrector bracket from summit. Full throttle is full pressure. The trans is working good. But downshift points are too low. It still doesn't drop overdrive until about 30mph. Which is only 700rpm. And at that speed, opening the throttle to downshift just about kills the carbureted engine.

 

It needs more TV pressure. You need to change something so that TV is higher at any pedal position than it is now.

 

Qualifier #1:
I'm not an AOD guru

rather than guess, would be best to put a gauge in the pressure port and KNOW what pressures you have at idle. My guess (from my experiences with AOD's and aftermarket carburetors), is that your TV pressure is too low at idle, as state above, and that the geometry is wrong (even though you bought the geometry kit).

summit sells some TV cable kits that may help you in your quest for a solution as well. switching to a cable should eliminate geometry issues associated with a kickdown rod.

here's some good discussion on the pressure requrements:
Any tips on adjusting TV cable on my AOD - Mustangsandmore Forum Archive

Question for the guru's:
could this also be a governor issue?

 

I am running a lokar cable. Right now, idle is closed and full throttle is full pressure.

So I'm gonna have to design some kind of linkage that hits full pressure at like half throttle, but then doesn't pull the cable out of place when it goes past that. Something spring loaded.

 

wishing they made these 15 years ago when i was messing around with this stuff.

TV Cable Corrector Kit - AS5-05K - Sonnax

looks to be the same thing as the TCI kit from summit.

everything i'm reading about it, this is very likely the solution to your problem.

 

I've got one of those. It helps, but there is still a problem.

Today I took it out and got on it hard for the first time. I went to WOT and held it there. It revs up to about 4k in first gear before shifting to second. But this shift is VERY SOFT even at full pressure. I think this points to a valve body problem right?

I'd love for it to bark the tires on a wide open 1-2. I have an assembled TRANS-GO valve body that I built. Maybe I could install that and see what happens.

 

There are a different governor valves and weights, there are different valve bodies with different springs and valves tailored to different types of cars and trucks. So the combinations can be many different configurations, this is what makes using hydraulically controlled transmissions in different applications so tricky. Even a higher rear end ratio can spin the drive shaft faster than the governor is calibrated for, so the tranny "thinks" its going faster than it is.

Using a different valve body even with the shift kit can give you different results, so give it a shot maybe it will be the right combination for you. I am not a fan of Transgo in this transmission but still try it.

The aftermarket cable system with an aftermarket carb and bracket may make adjusting the TV pressure with a gauge a little difficult, so I am not sure how to go about that with your set up. On a stock setup I use a 5/16 shim between the cable end and the bracket and set the TV pressure between 25-30 psi at idle.

The minimum TV pressure is 0-14 psi and the max is 74-92 psi.

 

James,

what's your thoughts on using a constant pressure valve body in applications like this?

any experiences with them?