only time I've ever seen a problem is a new converter installed empty.. but its been so long..

but all the scenarios I can think of all lead back to the quality of the folks doing the work. not the mechanicals..

Sam

 

For the sake of a full autopsy on these transmission problems here is what I was told on the (2) failed AOD's.

Transmission (1) from Monster Trans - Per Monster here is what they sent after looking at the returned unit - "The head builder said the unit became quite hot, he is surprised it did not catch on fire. He said that the pump gear wore grooves into the input drum. The gear did not
seat properly onto the torque converter shaft, that is why the ends were damaged. The seal is glued to the unit."

Transmission (2) - From my local restoration guys "Our tranny was in great shape, but sat for a couple of years unused. The clutch packs drain dry,and usually they just get wet and function again when you do use them...in some cases, like this one, they grab and destroy themselves before they get enough fluid movement in the clutch pack. There's nothing you can do except rebuild it right off the bat, and generally they do work, so it's not something considered worth doing- the chances of it eating itself are small, we just got unlucky"

Not real sure what to think of these explanations - won't affect the outcome of the truck - we press on expensively - I am following up with Monster to honor their 3 year "guaranteed handshake warranty".

Ben in Austin

 

You know, there's something else here that you might want to be checking if you had a pump failure right out of the box. It could have caused both failures. It's real easy to use the wrong flexplate. A lot of guys know that there are two different tooth counts or diameters (157 or 164 tooth) and a most also know that there are two different imbalance factors also depending on the engine (28 oz. or 50 oz.). The thing that can get you into trouble that many people DON'T know about is that there are also two different DEPTHS! For your rig, you need to use a 164 tooth flexplate with 28 oz. imbalance that was designed for the AOD or a C4. You can NOT use a C6 flexplate with an AOD. It sits the converter too far back and it will trash the pump and converter as soon as you start it up. Remember when I mentioned building an AOD this year for a friend's Bronco? This is why. We used the wrong plate when we swapped the 351W into the truck. With the engine and tranny bolted together tight and the converter nuts not installed, you should be able to wiggle the converter easily if you have the right plate. If it's clamped tightly in place, something is wrong. If it's been ran that way though, all bets are off. It might wiggle in there after it's had a chance to grind itself some clearance. Unfortunately, if one has been ran with the wrong plate, the whole transmission has to come back apart as it will pump metal shavings all the way through it.

 

You posted again while I was typing. "The pump gear wore grooves in the input drum." WTF?!? There is no such thing in there as an input drum. Moreover, the pump gears drop into the pump housing during assembly and the stator support is bolted tightly over the top of them. They're completely enclosed and isolated from all of the drums and other rotating parts. Idiots or liars - you decide. I don't think that I'd want anything they'd built in any of my junk.

I don't buy the second explanation either. A set of clutches that were properly soaked in ATF during assembly will NEVER "drain dry". The friction material is like a sponge. Beyond that, the pump starts blowing fluid all over the place in there as soon as the engine starts. They'd have been coated with fluid before you ever got it put in gear. Sounds to me like an assembly mistake that resulted in improper clamping force - or metal contamination from a torn up pump! See my comments above.

 

BOR, I think they are talking about the pump cover, from the description. I can sympathize on using the wrong flexplate, there is a dizzying array of FP's for the C4's over the years, I can only imagine what it's like for the AODs.

Ben, was the TC installed dry?

 

wow.. thats something I didn't know. With the ford bolts on the converter it would be hard to tell this was a problem during bolt down...

but, its still an installer problem vs a tranny hardware problem.

Sam

 

One size don't fit all when it comes to fords, every time I put an engine and transmission package together I have to hit the books and check casting numbers. The AOD is a good transmission but I'm partial to C5s and C6s.

 

Thanks again guys - After reading blueoval's piece on flexplate differences I'm going to make sure we don't bring the one that's been used so far. We'll take a hard look at flexplates before Round 3 - I wish I was learning this stuff on "bumpers or fenders" - it's expensive to learn on transmissions.

My restoration guys have offered to install AOD #3 for "free" - I think
I'll punt & change quarterbacks - maybe go with that Baylor guy for this next one.

Ben in Austin

 

Have whoever supplies the trans and TC supply the flexplate

 

I am glad I do my own work! Then I know who to chase when things don't go as planned!

 

If you want to get a new flexplate just as preventative medicine, I can guarantee you that this one is the correct part for a 351W with an AOD and is the best price you'll find:

Flywheel, Ford C5 / AOD, 289, 302, 351 engines | Ford flywheels | Transmission Parts by Bulkpart

They are obviously easy to get as an aftermarket replacement, but it's not a real common plate to find in salvage yards. There were only a few limited applications where Ford used an AOD/C4/C5 behind the 351W. Those transmissions usually ended up behind the 5.0L which has a different crankshaft imbalance factor. The 351W usually got the C6 or the E4OD - both of which use the deeper plate that will NOT work. We used the one above after we found the problem and were pleased with it. The quality and fit were excellent. The price was just a bonus.

 

Hi Jeff,
I brought this dilemma out in the open forum here to to highlight some of the pitfalls out there so others won't swim in the same pond hopefully.
Transmissions are pretty technical - I don't think the average weekend warrior is going to succesfully tackle the rebuilding of an AOD transmission.

A lot of guys I've talked with have lost a transmission in the build process - not sure what to learn here. I think I wouldn't buy one on-line from a big place - I think I'd go with your local transmission place where you know their work & get a solid warranty.

I just don't think I'd do any better getting a salvage yard transmission & installing it myself - Maybe - but these AOD's really need to be set up with the right pressure adjustment or they fail right up front after a few miles. Not sure that's a do-it-yourselfer deal there.

We are still good here - trying to get it on the road for New Years.

Ben in Austin

 

BOR I bookmarked that one!

 

Howdy,


I am not all that familiar with the AOD but I do know that there can be a problem with them if the TV adjustment is wrong....


I didn't chose an AOD because I want something a little stronger (and I wanted to be able to put a parking brake on the back)


I DID chose an E4OD because they ARE made for HP and are put in trucks that have GVW's up to 16000lbs and GCVW around 20,000 lbs. I don't think you'd break one.


I am putting one above in my 55 F-600 and I'll have nowhere near the HP you have with my 292 Y-block!

I am also using a Baumann Engr TCS controller. You could easily find an E4OD that would bolt right up to your 351 I think.
(in fact, I think the one I have will bolt to a 300 I-6, 302 and 351.

The above "transmission" originally came out of a 1994 diesel F-450. A friend of mine got me another case (the diesel bell housing isn't even close to adapting to a Y-block!!) and removed the internals and rebuilt it using the SBF/I-6 case/bell.

The E4OD's can be built to handle just about any HP you can generate.

I also have heard that the AOD can be built pretty strong too, but if you don't get the TV cable set right you can break it pretty quickly.


Good luck,


Rick

 

Thanks Joe? Blueoval,
You have been super helpful - I'll take a look at those.
I'll take some time Monday to go retrieve my truck & bring it home -
Sam gave me a good line on a local trans place he has used. Hopefully I'm headed on the right path - this just isn't an area I know well. I don't like getting taken but if we are driving in a month or two it will lessen the pain. My son is home from college at the end of next week & we can get some good work in over Christmas break.

I'll post some pics when we get it running down the road.

Ben in Austin