So I have installed a 331 stroker with an AOD trans in an early Bronco.

The question is...

What is the correct procedure for getting the lock up converter to function? How does it need to be wired?

Thanks in advance for the help!

-Joe

 

If it is an AOD it does not have a lockup convertor.

AODE has the lockup version.

 

If it is really an AOD it doesn't do anything electrically. When it shifts to third gear it does a partial lock, and it does this mechanically, not electrically. In fourth gear it has a full mechanical lock. If it is an AODE, then it is electrical.

 

I've never understood how the partial lock in third gear is supposed to work, or how it achieves or is considered to be partially locked.

I understand the torque split between the inner and outer input shafts, but now that torque split translates to a partial lock - other than that the inner shaft is splined to the converter housing and the outer shaft is splined to the turbine.

I understand that the turbine could be turning slower than the engine, but now how this translates to a partial lock since it also drives off the inner shaft which is splined to the housing and can't over run or under run the engine speed.

I've had several aod cars in the past with tachometers and I've never noticed that engine speed varied in 3rd gear for a given speed. That is to say at any given speed, the engine rpm is always the same regardless of engine load, indicating to me that it is locked up in 3rd, via the inner input shaft.

Not trying to argue, but I've just never understood how it can be partially locked when one of the drive elements is splined to the housing, unless something internally is slipping or over running. And I it is over running, how does it provide 40% of the input?

 

I've never understood it, either. If I had ever worked on the AOD I would have taken the time to learn everything about it, but I was never assigned to that transmission.

 

Do you have a TV cable or linkage, or did you spring for the constant pressure valve body? You can find TV cable adjustment info on this site or with a search.

Constant Pressure - TCI® Auto

 

It has a TV cable on it. All Lokar components for the TV and shifter.

There is a four pin connector on the LH side of the transmission. I am using two of the pins for the neutral safety functions. I just figured the other two pins would be for the lock up converter. Guess not?

I figured you guys would know.

I know on my 99 F350, if you are just tap the brake (so the brake lights activate) you can watch the tach increase a few hundred RPM when the converter unlocks, and then drop when it locks back up.

I just got my 86 F150 running after almost a decade! It looks to have the same trans in it. Once I get current tags on it, I can try the same test.

The Bronco drives real nice!

https://www.facebook.com/jmsservicecenter/

 

Found this...


Automatic Transmission Identification Guide - FORDification.com


Ford's automatic overdrive (AOD) for rear-wheel-drive applications was the first of it's kind offered by an American automaker back in 1980. Featuring mechanical lockup, it was available behind everything from the 3.8L V-6 through Ford's Windsor-style V-8s (the 5.0L and 5.8L). The later automatic overdrive electric (AODE) incorporated computer control.

According to Mike Stewart of Mike's Transmissions, one of the most common problems with the AOD is its tendency to burn up the overdrive band. Mike's Transmissions offers a variety of parts to bolster the capabilities of the AOD, including an "A+" servo with grater capacity than stock and a hardened 4340 chromoly input shaft to replace the notoriously weak lockup input shaft. Mike's Transmissions also retrofits the larger and stronger drum/band assembly from the newer AODE to non-electric AODs. Stewart considers a well-prepped AOD to be capable of withstanding 700 to 800 hp comfortably, making it safe for use in street applications less aggressive than all-out race cars.



Canada's Lentech Automatics has a reputation for building the world's toughest AODs. When asked about the weakest link in the AOD, Lentech's Chris Nugteren quickly points to an inherent problem with the power flow through the transmission. The AOD incorporates a somewhat rudimentary overdrive design featuring two input shafts. The inner shaft, which is driven directly from the front cover of the torque converter bolted to the flywheel, provides direct drive in Third gear and bypasses the hydraulically driven components of the torque converter entirely; the hollow outer shaft is driven hydraulically by the converter and drives First, Second, and Reverse gears. This is commonly referred to as a split torque path, and it allows 40 percent of the engine's torque to be transmitted via fluid coupling (through the torque converter) and 60 percent to be transmitted mechanically while the transmission is in Third gear. In Fourth gear, 100 percent of the torque is transmitted mechanically - similar to the direct-drive of a manual trans.

When building an AOD transmission for a mild street/strip applications, Lentech first substitutes a nonlockup-style torque converter, which allows hydraulic damping to reduce the shock transmitted to the inner shaft compared to a lockup converter. Another benefit of the nonlockup converter is that Third gear now receives torque multiplications from the converter rather than being driven directly by the crankshaft as with a manual transmission. The result is more potential speed and smoother operation without the lockup feature. Lentech offers hardened inner and outer input shafts in the standard spline count.

Another major component of the AOD that needs to be addressed in a performance applications is the valvebody, which, in Nugteren's words, "has a shift pattern that sucks." The AOD was introduced at a time when Ford's automatic-equipped cars rolled off the assembly line with only three-position column detents. Rather than design a new column, Ford (during it's "Better Ideas" days) opted to provide only three shift positions for the new transmission: First, Drive, and Overdrive, bypassing Second gear entirely in a manual-shift situation. Mustang owners quickly learned that if they upshifted from First to Third (Drive), then quickly downshifted back to First before the trans made the shift into Third, the trans would hold Second gear until the driver manually upshifted to Third.

While this technique will work for a while, the overdrive band and direct clutch will prematurely wear out. Lentech changes the shift pattern by making a specific gate for Second gear and combining Overdrive with Drive. Overdrive is controlled with an electric solenoid in the valvebody (like most overdrive transmissions).


Lentech covers mild, but what about wild? The company starts by replacing the two-piece input shaft with a one-piece nonlockup 4340 chromoly unit (see photo) offered in two states. Stage One shafts feature a standard spline count, while State Two one-piece input shafts are offered in larger diameters and feature higher spline counts. They also offer a matching direct drum and torque converter.


Fig. 04 - Ford's AOD comes equipped with a two-piece input shaft (left) but Lentech Automatics offers a one-piece 4340 chromoly replacement to handle brutal horsepower.


Next, the valvebody is replaced with a Lentech unit that applies two clutch packs to Third gear. Normally only the direct-drive clutch pack would be used, but the reverse clutch pack is added to the function, spreading the load over two sets of splines and friction elements (drums), and allowing it to hold huge horsepower. It's this single development that has made Lentech's ultimate AOD transmissions virtually bulletproof. They further modify the transmission by removing the Fourth (Overdrive) gear and replacing many of the components with lightweight pieces. In applications where a "loose" or high-stall converter is used, Lentech maintains the lockup function of the converter, enabling it to eliminate the slippage that plagues high-stall converters. On of its race units is in a Mustang running 8.20s at 165 mph with no breakage in a full season's use. We would say that it works!

The AODE is essentially an electronically controlled AOD transmission, sharing most of its internal parts except for the input shaft, which has its lockup function controlled electronically by a computer. As mentioned above, the drum/band assembly is slightly larger and made of stamped steel (unlike the cast-iron drum used in the standard AOD), and it is interchangeable with its counterpart. One advantage enjoyed by the AODE is that the shift functions and characteristics of the transmission can be programmed for greater versatility, but this creates its own unique set of problems.

Ford programmed the AODE to provide seamless transitions between gears, accomplishing this with a pressure-control solenoid (PCS) that manipulates the line pressure in the transmission to soften shifts. Ford also attained seamless shifting by slipping the converter clutch, which cycles the converter in and out of lockup. Unfortunately, this prematurely wears out the clutch materials, which can send debris through the system. Lentech insists that the first thing to do with an AODE is to add a performance computer chip that corrects the pulse width of the PCS and eliminates the multiple personality of the lockup feature.

 

This is a pretty decent article as well. Still no explanation on how to wire the lock up converter though...

How to Build the Perfect AOD - AODetail

 

AOD does not have a lock up convertor.

 

That's because NOTHING ON AN AOD IS ELECTRONICALLY CONTROLLED. You would have just as much success wiring your front bumper to be a lock up converter.

Not. the other two pins are for your backup lights.

 

Always wanted a lock up bumper.

 

After re-reading one of my own posts (duh), I see how 4th gear is locked up. It's that direct drive deal off the two piece input shaft. 4th gear is always locked up.

At least now I know that I'm done with this Bronco. And what the other two pins are for!