How To Build A Bullet Proof AOD 101

[1windsor1]

Sorry to wake this from the dead...but first post.

So what are the two primary items that strengthen the AOD, the 1 piece input shaft and the Lentech VB?
On a quality rebuild with just adding the above items and proper cooling and convertor, what kind of power can someone expect to run through one?

Thanks!

[SilverFox]

Depends on what you call PRIMARY upgrades.
IMO, a mechanical diode, 2" OD band, shift kit, stamped steel direct drum will make the AOD about as bullet proof as it can in a relitively stock manner.

If you want for sure to bullet proff, then you add the ONE peice to that mix, and more pressure.

[DirtyD0g]

Aod's seem to be endless on upgrades with each one needed at some point. A friend of mine had to use a 4r70w extension housing, yoke and a markVIII output shaft to keep his together. IMO after you fix the stock weak internals you need a good valvebody and a good tv cable setup. The OEM setup works fine if it is in good shape. THey are getting harder and harder to find good cables for and Lokar seems to be the only option.
Alan

[1windsor1]

I never thanked you guys for the info. Thanks!

[DirtyD0g]

The next piece to the puzzle has become the 300m direct drum tower. Overkill for most, but for the guys who just can't keep an aod together.
Alan

[gigamortis]

Aod's seem to be endless on upgrades with each one needed at some point. A friend of mine had to use a 4r70w extension housing, yoke and a markVIII output shaft to keep his together. IMO after you fix the stock weak internals you need a good valvebody and a good tv cable setup. The OEM setup works fine if it is in good shape. THey are getting harder and harder to find good cables for and Lokar seems to be the only option.
Alan

I can add some more real world experience here on output shaft issues. I once had a customer with about 600rwhp that managed to kill even the 4R70W output shaft. After studying his car over, I found that he was still using the factory rubber bushings for the upper control arms! They flexed so much on launch, that his pinion angle changed drastically to the point of setting up a massive u-joint angle mismatch from the rear joint to the front joint. Wheel hop was nasty, too. When you have a setup like this, the vibrations set up by the rear u-joint cannot be cancelled out by the usual opposite amplitude arc swing of the front u-joint, so this amplitude of energy finds somewhere else to go. Simply put, driveshaft vibrations during launch were so severe, that he broke his driveshaft, output shaft, extension housing, and made a crack all the way up at top of the bellhousing for 180 degrees. And that was on a good 5 rib AOD case!

This same car had also killed 2 reverse/OD sun shells before this by cracks originating in the bottom corners of the engagement lugs. The shells were cracking despite my usual practice of filing a radius at the bottom corners of the lugs to get rid of a stress riser at these points. I always radius all the bottom corners of the sun shell lugs on any high horsepower build. This had been the only transmission that I ever had recurrent problems on sun shell cracks. After finally seeing the car in person, noting the wheel hop, and the eventual major damage created by the chassis problems, I can attribute the broken sun shells to the severe driveline vibrations on launch. I have never had any other high horsepower customers going through sun shells like this particular one.

When you get up in the 450+ horsepower range, it is time to really consider getting your chassis right, or else you will be killing axles and transmissions.

[DirtyD0g]

Speaking of which just last week I got a new thicker sun shell. These parts get better every day. I have some mods I make to them to improve them even more.
Alan

[gigamortis]

On that thicker sun shell you came across, what factory application was that for? I would love to find a more durable piece for performance builds. Of course, the rarest shell to come by lateley is the shorter 2.40 ratio gearset shell that lets you run a 2" OD band in a regular AOD. These were only made by Ford for the short application year span of the AODE. After that short run of just a few years, that AODE transmission went to the wide ratio 4R70Ws.

So far, I am beta testing some of the newer factory stainless sun shells in high horsepower wide ratio applications for durability. They are stainless because they need to be non-magnetic for the 4R70E model's turbine shaft speed sensor to get a reading. There are trigger nubs on the OD of the forward clutch cylinder for these 4R70E models that are counted by this new sensor. The sensor has to be able to read through the non-magnetic sun shell to get a reading.

The part # for the factory stainless shell is 5L3Z-7A019-AB. The gear on this shell is slightly shorter front to rear so it requires the latter two piece thrust bearing between it and the forward sun gear to keep your stack height and endplay the same. Keep this in mind when you build up an earlier year wide ratio build. The latter short gear measures 2.023" front to rear while the earlier one measures 2.058". This .035" difference is handled by the early vs. latter thrust bearing thicknesses which themselves differ the .035".

[SilverFox]

..I have not had the problem, however I have more than one 4x4 guys call about keeping the SS shell from splitting apart like a coke can with an M80 in it.
The shell sees some serious rpm in 3rd.

[gigamortis]

Yeah, the sun shell is spinning at crankshaft rpm and direction in 3rd. It's really hauling ass even faster in 1st gear while it is freewheeling in the opposite direction of the input shaft. It isn't carrying any power in 1st, but it is forced to just go along for the ride by the action in the planet gearset while the planet is making 1st gear ratio. That poor sun shell sure comes to a screeching halt when you hit 2nd, though, in order to make the long planet pinions walk around the newly stationary sun shell and gear. The shell starts moving again for 3rd when the intermediate one way freewheels upon 3/4 clutch applying. Then the poor thing has to stop again for OD. Whew!

Sounds like this sun shell really catches hell, doesn't it?