See owners manual page 97 (section about overdrive).

Mine will not shift to overdrive until I let up a little on the gas pedal. It is supposed to be normal.



Here is the next page with other info about the AOD transmission.

 

See owners manual page 97 (section about overdrive).

Mine will not shift to overdrive until I let up a little on the gas pedal. It is supposed to be normal.

Look, I know your just trying to help.

And that is awsome :thumbup

But man, I've had my Bronco for for 15 yrs and 380,000 of it's 480'000 miles. It has had 4, AOD's in it since I have had it.

My Mustang has one.

My old Thunderbird had one.

I know exactly how they are supposed to act.


I have gone so far as putting a pressure gage in the test port and comparing it to the specs in the service manual.

The owners manual is not going to help.

But, in all seriousness. I do thank you for your attempt. :beer

 

heyy the guys just tryin to help so dont stress out..

 

I agree with you 100% :thumbup

And thats why I sincerely thanked him for his attempt :beer

 

Maybe you just don't have the AOD's TV cable set as well as you think you do. I haven't been through 15 of these trucks, only 2 AOD's, but mine seemed to shift pretty well after adjusting the TV cable. Maybe its in the "extra" stuff you put in the tranny.

 

Maybe you just don't have the AOD's TV cable set as well as you think you do.

And set the TV to be at max at WOT.

I have gone so far as putting a pressure gage in the test port and comparing it to the specs in the service manual

TV pressure is almost 20psi at idle and climbs as soon as you breath on the throttle.

I have watched the TV pressure very closly during the 3-4 shift, there does not seem to be a drop. I can post pressure readings @ RPM and throttle angle if you think it will help the diagnosis. I can even post a vidio if I need to take one.

Maybe its in the "extra" stuff you put in the tranny.

This anomaly did not appear until the Bronco sat for several years, and before I modded the trany. The modifications helped the problem tremendously, they did not create it. But they did not completely cure it either.

 

After re reading my reply to jem270, I realize I was being a bit "bitchy". So I edited out some of the more smart-but remarks.

What can I say, even I get grumpy sometimes.

I feel I do owe him an explanation of what the manual says, and why it does not apply to my situation.

A 5.0/302 was the largest engine placed in front of an AOD in a fullsize truck/Bronco/Van. This was not a terribly powerful engine for the weight it was asked to haul around.

The AOD was Fords first Automatic that had a 4rth speed (Overdrive). In stock form the AOD is programed for low RPM soft shifts and can not shift to 4rth at 3/4 or greater throttle. The limit on the shift to 4rth is to save the overdrive band from slipping on the drum because of the weak "B" or even weaker "C" overdrive servo's that where installed at the factory. The AOD will also try and hold overdrive for as long as possible before downshifting to 3rd.

Like any other automatic, the harder you press the throttle, the higher the transmission holds a particular gear before up shifting. That includes the shift to overdrive.

Now, here is where what your owners manual says comes in. See, on level ground, or a slight incline, the stock 302 does not have the power to push your Bronco to the point where the TV load is low enough at a given RPM to make the 3-4 shift before reaching the 3/4 throttle limit. But, if you let up on the throttle slightly, the load drops and it makes the shift. Now, once in 4th the AOD will try to hold overdrive to a higher TV pressure than it took to shift to 4rth.

So affectively , once you let up and it shifts, you can press the peddle farther than you had it before and the AOD will still hold overdrive. And it is simply an issue of power to weight.

This is a simple version of it.

Why this doesn't apply to me.
357W with GT40"x" heads, Car style Edelbrock intake, crane powermax cam, BBK headers, and a whole lot more.

My 357 has more than enough power to push my Bronco up a moderate incline wile making the 3-4 shift. That is why I had to install the TCI "super overdrive survo" It is an A++ unit that has 4 times the clamping power of the puny "C" servo I found in my AOD and more than Fords strongest "A" servo.

Even my old 302's had enough extra done to them to make the 3-4 shift on level ground.
(And even a verry slight hill)





Now since I have a bad habit of not wording things in a way that makes sens to anyone but me.
(I really am a poor teacher/explainer when it comes to writing :cry)

Did I do an ok job of explaining this one? :beer

 

"After re reading my reply to jem270, I realize I was being a bit "bitchy". So I edited out some of the more smart-but remarks."




You mean there were more demeaning bitchy parts than what is in there now?

Wow. My feelings are really hurt now.

Makes me want to trade for a blazer.

 

Wow. My feelings are really hurt now. .

Would a hug help? :hug

I always feel better after one :toothless

Makes me want to trade for a blazer.

Wow, now that Reaaalllly hurts :cry

 

LOL its all good. :thumbup

 

Gack ur suppose to be the AOD king here. If you dont know good luck finding
someone who does

Who else do you know that has a trans pressure gauge permanently
mounted under the hood of their Bronc?

 

Gack ur suppose to be the AOD king here. If you dont know good luck finding
someone who does

Some one always knows more than I do. :toothless

Who else do you know that has a trans pressure gauge permanently
mounted under the hood of their Bronc?

That was only supposed to be temparary, but I liked it so much I left it :histerica

 

Well, I still have this goofy 3-4 shift, anyone got any more advice?

I think I am going to try to contact a few aftermarket suppliers with tech support, maybe one of them can point me in the right direction.

 

I think I am going to try to contact a few aftermarket suppliers with tech support, maybe one of them can point me in the right direction.

I sent an E-mail to tech support at two different companies about an hour after that post. One of them has already gotten back to me :rockon

Jim G. At Monster Transmission & Performance
http://www.eatmyshift.com/

Says I may have a sticking governor, I guess this is the next place I will look.

I love fast customer service (technically I'm not even a customer yet) and several folks on here are very pleased with there Transmissions. I recommend checking them out if you are in the market for a new Tranny.


The governor is 90-101 on this page
http://www.tcsproducts.com/file_library/downloads/9_AOD%20Transmission%20Schematic%20LT%20pgs1-3%20April08.pdf

 

just throwing this out there Gack, when was the last time you performed a complete flush of the system? draining the converter, lines and cooler? are you running regular tranny fluid or synthetic?

 

just throwing this out there Gack, when was the last time you performed a complete flush of the system?

When I installed everything, about 6,000 miles ago.

are you running regular tranny fluid or synthetic?

Regular

 

Did you try different adjustment on the TV cable? I remember messing with the adjustment a little bit and it seemed to change the shifting.That was a 88 tranny in a 4x4 ranger with a 302 efi swap i did a few years ago. Just a thought

 

Yup :thumbup

TV pressure is almost 20psi at idle and climbs as soon as you breath on the throttle.

I have watched the TV pressure very closly during the 3-4 shift, there does not seem to be a drop. I can post pressure readings @ RPM and throttle angle if you think it will help the diagnosis. I can even post a vidio if I need to take one.

This setting gave me the best results.

 

Gacknar,

Did you buy and install one of those BBK throttle bodies on your intake when switching to 351?

If so then the vacuum values would be much different at throttle positions infact the changes in vacuum would be at much greater incriments due to the larger surface area of the TB assy.

This would make adjusting your TV cable much more tricky....no?

A possibility? If you didn't change your TB assy then I am full of it!!:whiteflag

 

Vacuum has NOTHING to do with the AOD. Strickly controlled by throttle pressure.

 

i have this same problem mine sat for a year. ive actually been messing around with it trying to get it figured out my self not to the exstent that u have. i just figured it had to do with the stering column being broken after some one tried stealing it. so that being said does urs do it all the time couse after a long trip say 200 miles or so mine acts like it doesnt do it any more but the next day it will start all over again.

 

Im gonna keep an eye on this one. My AOD slams in to OD sometimes and others its nice and smooth. Thinking of going to the E4OD what do you think Gack? Good luck with this.

 

Swapping to an E4OD would require a new pcm, and OD-OFF button and a new wiring harness or extensive modification to your harness. Stick with your AOD unless you have a donor Bronco with an E4OD and all the parts. E4OD's are definitely not without their own headaches(plenty of them).

 

Welp it's not the Governor.

Pulled the T-Case and extension housing. Pulled cleaned the governor.
(It was not hung up)

Put it all back together and there is no change of any kind :cry

 

Gonna take two shots in the dark, here:

1.) The OD band hardened/glazed while sitting and the friction material no longer creates "friction" adequately. This would explain why the shift kit and servo upgrade helped, but, didn't entirely solve the problem. More apply force, but, shot OD band.

2.) The lockup damper in the torque converter that controls when the direct drive shaft takes over to engage fourth gear and disengage third.

If it were my AOD, that's what I would inspect next.

Just my $0.02,
Eric

 

Wow, thanks for reading the entire thread. As old as it is I didn't really expect any response.
:thumbup

If it were my AOD, that's what I would inspect next.

Thank you for the advice. :thumbup

But at this point, I'm just gonna let it ride.
(Unless someone has a definitive, and exact answer)

When it burns up, I'll buy a unit from Monster and be done with it. :toothless

The lockup damper in the torque converter that controls when the direct drive shaft takes over to engage fourth gear and disengage third.

I'm actually not familiar with this. Can you point me to some information on it?

I would be greatfull.

Thank you :thumbup

 

The "damper" is more of a function than a, specific, part. To be honest, I have never, actually, seen these pieces because they exist inside the torque converter. Never had to split one open. :toothless

What I do know:

When the vehicle is in 3rd, the converter has a 60%+ slippage rate. As soon as certain operating conditions are met and the fluid coupling is high enough, the "damper" function diverts the power to the direct drive shaft.

As far as info on how the fluid coupling "damper" works, I hope you like to read and have a cup of coffee ready:

The torque converter is bolted to the flywheel between the engine and automatic transmission or transaxle. It takes the place of a clutch, but does essentially the same thing as a clutch without the need of a clutch pedal. It transmits power from the engine to the transmission, but also allows a certain amount of slippage when the vehicle is stopped in gear so the engine doesn't die. It also acts like a reduction gear to multiply torque when the vehicle starts to move.

If you could peek inside a torque converter, you'd see what makes it work. Inside are three wheels with curved blades: the impeller, stator and turbine wheels. The torque converter is filled with automatic transmission fluid, so anytime it rotates fluid is slung around and around in a circular path between these bladed wheels. The motion of the fluid is what actually transmits torque from the engine to the transmission. Here's how the fluid coupling works:

FLUID COUPLING:
The impeller is attached to the outer torque converter housing and is the drive member in the coupling. The impeller slings fluid toward the turbine wheel when the converter housing rotates - which is anytime the engine is running, whether the transmission is in gear or not.

Facing the impeller is the turbine wheel, which is the driven member in the coupling. When fluid from the impeller strikes the turbine blades, it causes the turbine wheel to rotate. The greater the force exerted by the fluid, the greater the drive torque transferred to the turbine wheel. A splined shaft couples the turbine wheel to the transmission input shaft so when the turbine wheel turns, it drives the transmission.

Sandwiched between the impeller and turbine is the third wheel, the stator. The stator's purpose is to multiply torque by completing the fluid flow circuit between the impeller and turbine. When the fluid slings off the impeller and hits the curved blades of the turbine, it has to go somewhere. The stator's job is to redirect the fluid back toward the impeller. This gives the impeller an added boost and keeps the fluid circulating in a circular pattern called "vortex" flow.

TORQUE MULTIPLICATION:
The stator wheel is mounted on the converter hub and floats on a set of one-way roller bearings. The one-way clutch allows the stator to rotate in one direction, but not the other. The stator's blades curve in the opposite direction of the impeller and turbine blades. At idle, fluid coming off the turbine blades hits the stator blades in such a way that the stator wants to turn the wrong way. It doesn't spin, however, because the one-way clutch holds it tight. As a result the fluid slings back toward the impeller.

As long as the impeller continues to turn faster than the turbine, torque will be multiplied and the converter will act like a giant reduction gear. The amount of torque multiplication is usually about 2:1, which is like slipping the clutch when starting out from a dead stop. The added torque helps get the vehicle moving without lugging down the engine.

As the vehicle starts to move, the speed of the turbine wheel starts to catch up with that of the impeller. As the speed of the turbine approaches 90 percent of the speed of the impeller, the fluid dynamics inside the converter change. The fluid flows at a much steeper angle and now strikes the stator blades from the backside. This pushes the stator in the right direction and starts it turning. As soon as the stator starts to spin, however, torque multiplication is lost and the converter "locks up." The stator freewheels at the same speed as the turbine and impeller, and the three elements become a fluid coupling.

The hydraulic lockup that occurs is not the same as the mechanical lockup that occurs in a torque converter equipped with a computer-controlled mechanical clutch. Because there is no mechanical connection between the impeller and turbine wheels, an ordinary torque converter will experience up to 10 percent slippage between the engine and transmission. This hurts fuel economy and performance, so the torque converters in most late-model vehicles have a computer-controlled pressure plate that locks up against the housing when the vehicle is about a certain speed and/or is in higher gears. A computer-controlled solenoid controls the flow of hydraulic pressure from the transmission to apply and release the pressure plate. When the plate is engaged, there is no slippage between the engine and transmission, and the torque converter acts like a solid member in the driveline. But when the brakes are applied or the vehicle is idling with the transmission in gear, the pressure plate is released so the torque converter can slip.


Eric

 

Sorry for the double-post.

Gacknar, after the awesome 5.0 HO EFI advice you gave me, I owed ya big. Was beating my head against a wall for weeks with that problem. :banghead

Also, check out Silverfox transmissions, if you get a chance. Good guys, awesome products.

:beer,
Eric

 

Sounds like you might have a somewhat worn OD band and possibly a little 'flare' going on during the shift.

The AOD was designed NOT to shift under hard throttle so...your 1/4 throttle shifts sound correct, however your valve body might not be allowing correct timing (3rd gear letting go, so OD can engage).

The shift kit probably helped that some, since most have larger (or require YOU to drill larger) holes in the separator plate. This is done so fluid can either fill or evacuate more quickly from certain bores. The 'timing' of that 3-4 shift is critical.

Adding the upgraded OD servo was a good move (provided it is moving freely).

Your TV pressure at idle sounds a bit high (but might be necessary). I like to have mine between 1-5 lbs and the cable adjusted so that any movement gives an instant increase. Too little pressure will fry your tranny, I am sure you know. Conversely, too much makes for delayed shift points (and harder shifts).

If you do a 1-D-1 'shuffle' (accelerate hard from low, shift to D, then right back down to low) it should 'hold' in second gear (manual), if you then let off the accelerator you should feel prominent 'engine braking'. This would (to some degree) let us know your OD is still OK (not completely glazed or worn out).

DON'T do the above very often...as it is hard on your tranny.