1948 - 1956 F1, F100 & Larger F-Series Trucks Discuss the Fat Fendered and Classic Ford Trucks

AOD Help!

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Old 01-21-2015, 10:01 AM
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Question AOD Help!

Decided to write a separate post for the AOD to get more focused input. Here's where I'm at.

Working on my '54 F100 - swapped in a later model 302/AOD combo. I had picked up a rebuilt AOD from a guy who wasn't going to use it. It looked the part - clean, painted, new gaskets, even the right plugs and things in the ports, driveshaft, etc. and the torque converter was safety wired in complete with the proper nuts. However, it's been sitting in my garage for 2.5 years and who knows how long in the other guy's garage.

Anyway, had first real drive yesterday (been around the block a couple times) and it shifts fine 1-2, but after about 40-45mph, it seems to just move into neutral. It did shift into 3rd once, but same thing. If I pull over, I can drive away immediately, but once it disengages, it's like it's going into neutral.

I finished the drive (tag office & muffler shop) by doing the 1-D-1 shuffle so it wouldn't try to shift into 3rd - it didn't slip or neutral out when I did that, but I could only cruise about 35-40.

A few stats: stock '89 302HO from an '89 Mustang GT, the TV was adjusted to neutral (I will put a gauge on it tomorrow), fresh new Mercon V, and all stock AOD (as far as I know).

From the little bit of online research says it could be a couple of things. It seems to be related to the direct clutch. When a running AOD develops my problem, it's usually this area that is damaged. This one is supposed to be rebuilt (I know, I know...). I've also read that these trannys are finicky about their valve bodies and any little crud can wreak havoc. So, I'm wondering if it sitting as long as it did caused something to stick (hoping). I've also read it could be the inner input shaft broken (seems unlikely as I just installed it - and it did go into 3rd once), but...

So, tomorrow, I plan to verify the TV port pressures (0-5 at idle in neutral & 30-35 with 5/16" spacer on end of cable, and 80-85 at WOT), then if that works out, drop the pan and a) verify it is rebuilt, b) no nasty shavings/friction material in the pan, and then I'll drop the valve body and clean it up well, reinstall, and try my luck.

So apart from checking the TV port pressure - is there anything else I can do?

UPDATE:

Got a gauge on it this morning. When cold, the readings were pretty good:
Idle - 0 (could be strong/new internal bias in gauge as it "snaps" back to zero below 5-10psi)
5/16 - 35-38psi
WOT - 95psi

So, I let it warm up for a while. Good leak check (found one minor one) on a new build. Stayed nice and cool too, which is a bonus. Then I checked TV pressure again:

Idle - 0
5/16 - 40-43psi

So, I adjusted the cable a little bit - I'm using a factory style cable, so fine-tuning is difficult although just now, it appears the big square retainer may be threaded onto the cable sleeve - I'll check.

Now when I check it at 5/16", it varies a little - it started off around 35, but slowly rose to about 43 with a pretty steady idle speed. I'm starting to wonder if something is sticky inside.

For my 5/16" spacer, I took a 5/16" shouldered bolt, cut off threads and cut a slot in it length-wise. 5/16" bolts are really .305" instead of .315", so not sure how critical that last .010" is, but I assume I should ideally see a pressure reading on the lower side of 30-35 instead of the high side.

As for return spring on the TV arm, this is a factory cable and I verified it is returning all the way no matter what I do. No exhaust run yet, so I have free & clear access to both sides of the trans right now.

I'm going to see if I can fine-tune a little bit more, but if I keep getting this slowly rising reading, I'm going to drop the pan and see if cleaning the valve body does anything...as well as a good visual inspection.

Any thoughts??
 
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Old 01-21-2015, 10:22 AM
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I'd feel better if your gauge was known to be accurate. The below-10 psi performance hints at issues. 95 indicated vs. 80-85 spec'd is not out of the question to be an accuracy issue. I've had even S-W mechanical gauges be off that much.
 
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Old 01-21-2015, 10:33 AM
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The sad thing about the AOD is that if the TV pressure in not right before you go around the block you can fry the direct clutch and or OD band and their is no going back once that happens. Many of us on the form have learned that. I would drop the pan and check for clutch material. If their is any clutch material in the pan I think that you can figure out what the next step is.
 
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Old 01-21-2015, 10:38 AM
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Excellent point, Ross. It is a new aftermarket Bosch unit, but it's one of their cheap ones - a known good oil pressure gauge would be nice (I don't have one handy).

Turns out, there is no fine tuning on the factory cable, so I came up with my own solution that seemed to work. Insert the 5/16 gage, unluck the sliding block, then use needle nose pliers to carefully slide the sleeve out while monitoring the pressure - when the pressure is right, lock it down & recheck.

Since doing this, I've locked the TV pressure down. It still fluctuates mildly (33-38psi) very slowly, but stays within the limits. I'll take it for a test drive after lunch and a parts run for something else.

Even if this fixes the shifting, I'm still inclined to drop the pan anyway...only costs a few quarts & a gasket for peace of mind.
 
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Old 01-21-2015, 11:07 AM
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Not really familiar with the ford aod but am somewhat familiar with the symptoms you are having because my sons ot vehicle had the same symptoms. He changed the shift solenoids, he just dropped the pan and filter and they were right there, I think it took him every bit of an hour. I know in the chevy AOD one solenoid controls ths shift points 1st-3rd and the other controls the shift points 2nd-4th. Google your symptoms and and aod type and it will give you sites that will help you.
 
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Old 01-21-2015, 11:17 AM
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I believe this would be a pre-computer-controlled trans, no solenoids.

Chuck's right, these are sensitive as hell to TV adjustment with unfortunate results, but if your gauge is at all accurate you were pretty close to spec. Aren't the specs with oil hot, too?
 
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Old 01-21-2015, 05:01 PM
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A fella that I have rebuild my AODs said that unless in a heated garage, the OD band material has a tendency to separate from the band. Making the OD useless.
 
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Old 01-21-2015, 06:02 PM
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Yes, oil hot. I let it idle for 30 mins in the sun today and adjusted the pressure to 35. Well, and still didn't shift right. I immediately put it back into 1 so it wouldn't try to shift on its own and when I got back, I checked the gauge again - now it was reading 25. Moving the throttle, I can get it to go up and as it comes back down, it settles at 35, but it will go down to 25, up to 35...

Spent most of the afternoon replacing some connectors that were giving me issues with the ignition and chasing some other bugs. Tried again tonight to see if it was any different - same results.

I think it's toast, but I'm going to drop the pan first thing tomorrow morning since I'm out of daylight today...just to have a look-see. I'll trailer it to the exhaust shop afternoon - 1pm appt.

Maddening, but...I suppose you get what you pay for. Might have to pony up and have it done - or do it myself. I've done a few C6 and a 727, but it was years ago...nothing overly complex, but I do know there's one special tool I'll likely need if I attempt it myself....
 
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Old 01-21-2015, 06:08 PM
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Baumann's site has lots of tips, and explains the upgrades thru the years (factory). IIRC an 89 AOD wouldn't necessarily have the wider bands and OD servo upgrades, for that matter it may be a replacement. If you're in there anyway....
Baumann Engineering - An Introduction to the Ford AOD-E/4R70W and AOD Automatic Transmissions
 
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Old 01-21-2015, 06:28 PM
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Well, the '89 AOD is in the corner of the hangar. THis is a replacement, so there's no telling what the original application is. If I have to rebuild one, I think I'm going to bring both of them to the rebuilder...give him an extra core...I've got no other use for it, really.

BUT if I open it up, I'll look and see what's what. I've been all over Baumann's site and click-click racing and TCI and...

Back out to the truck! I don't have 12 hours on it yet today!!
 
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Old 01-21-2015, 08:52 PM
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Most common problem I have seen is contamination...more often than not it comes from the lines/cooler in the existing system where the new trans is installed. Drain the fluid and examine closely...
 
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Old 01-22-2015, 08:23 AM
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Lines & cooler and radiator are all brand new in this installation.

That doesn't mean it couldn't be contaminated. Out to drop the pan now...
 
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Old 01-22-2015, 08:32 AM
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Seems to me there was something about (CRS) some years being better than others. Something about the ribs on the case.
If you find particles in the pan, they're probably band friction material.
 
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Old 01-22-2015, 08:39 AM
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Here's something too - does anyone know the ratio of throttle movement to TV movement - my current setup favors TV. From the throttle shaft pivot point to the throttle linkage is approximately 1" and from the throttle shaft pivot point to the TV linkage is close to 1.5".

Can anyone check a stock TV linkage and see what the ratio is for me? I was just shooting for full TV linkage movement at WOT (something I read somewhere online).
 
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Old 01-22-2015, 09:13 AM
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Fuel injection??
Baumann Electronic Controls
How to Adjust the Ford AOD TV Detent Cable
I think there was some other info on Crown Victoria, Grand Marquis, Marauder, and Towncar

I've got a paper out in the garage...somewhere....
 


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