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Ford AOD Tech

Grnd93

Grnd93

The Dude
Joined
May 19, 2020
Member Number
236
Messages
738
Loc
Michigan
Trying to work through some issues with the AOD in my 86 Mustang.

Backstory for those of you not in chitchat:

Pulled a 150000 mile drivetrain out of a donor 86 5.0/AOD cougar and put everything in my 86 V6 Mustang a few years back.

Since then we built a fresh 5.0 with a few upgrades (GT40 heads, explorer intake, Anderson N41 cam). After putting the new engine in the car was still ver slow off the line (slower than the previous engine). We had never upgraded the torque converter, so at the recommendation of the cam manufacturer and Monster Transmission we put a 3200RPM stall converter in. At the same time we changed the shift lever in the trans to the correct style for a Mustang to match the floor shifter.

Off the line performance has improved, but now when it shifts from 2-3 the engine just revs with no 3rd gear engagement.

Aside from the possibility the the trans spontaneously lost third gear, what else should I be looking at?

I feel like my next step is to drop the pan to make sure we didn’t screw up anything when we swapped the shift lever. And I do want to properly set the TV cable. What else should I be looking at?
 
No expert on AOD's, but I've had a few issues with them over the years. Mostly related to the TV cable... like that being adjusted correctly is paramount to the thing operating without destroying itself. The proper way to do it is with pressure gauges, as you probably already know. I adjusted one in my Lincoln myself without gauges to "good enough" status. It went into OD a little before 45mph, and you could feel the shift from 3 to 4 would be weird. Eventually it frag'd the plastic accumulator for 4th gear I believe.

Could be something to do with 3rd. Also, AOD's (not AODE) has a second input shaft that splines directly to the TC shell. 3rd gear is supposed to be mostly mechanical, something like 40% direct drive and 60% fluid coupling once engaged as I understand it. Power flow for 3rd should be pretty simple so if something isn't working, you should be able ro figure it out. 4th is supposed to be 100% mechanical, as there's no lockup. once it's in 4th, it's just transmitting torque thru that second input shaft lugged right to the converter shell.
 
landen300 said:
No expert on AOD's, but I've had a few issues with them over the years. Mostly related to the TV cable... like that being adjusted correctly is paramount to the thing operating without destroying itself. The proper way to do it is with pressure gauges, as you probably already know. I adjusted one in my Lincoln myself without gauges to "good enough" status. It went into OD a little before 45mph, and you could feel the shift from 3 to 4 would be weird. Eventually it frag'd the plastic accumulator for 4th gear I believe.

Could be something to do with 3rd. Also, AOD's (not AODE) has a second input shaft that splines directly to the TC shell. 3rd gear is supposed to be mostly mechanical, something like 40% direct drive and 60% fluid coupling once engaged as I understand it. Power flow for 3rd should be pretty simple so if something isn't working, you should be able ro figure it out. 4th is supposed to be 100% mechanical, as there's no lockup. once it's in 4th, it's just transmitting torque thru that second input shaft lugged right to the converter shell.
Click to expand...
There seem to be 1000 different ways to set the TV cable. We had it set up fine with the old engine, but we started from scratch with the new one. I have a guage and the 5/16" block needed to adjust. I just need to get everything hooked up and do it.

I am hoping that when we changed the shift lever we didn't have the TV lever contacting the valve in the transmission. Everything seemed ok until we did that (in conjunction with the torque converter).

If all that checks out I'll pull the trans and make sure that input shaft is in correctly. It did slide out when we swapped the TC, so maybe we didn't get it seated properly? I'm grasping at straws right now. I'd like to have it moving properly at minimal cost for the rest of this season so we can save for a T5 swap over the winter.

Alot of people are saying I have destroyed the third gear clutch due to the TV being improperly set. I know that this is a possibility, but we have put maybe 5 miles on it with the new engine. Seems unlikely to me that it would happen so quickly, but maybe?
 
I'm not sure how fast it could happen... My Grandpa's Lincoln (the one I mentioned before) did a lot of sitting after he passed in 95. The car would only get driven when we'd vacation and visit them. around the 2002 time frame, my mom fired the car up and went around town running some errands. Her words were "the car's not running right, it's spark knocking real bad" My old man and I drove it, and it was upshifting way way early, and slugging down into a high gear and the load was causing the spark knock. The little nylon bushing in the throttle body that holds the end of the TV cable had disintegrated and fell apart - no TV pressure at all... Anyhow, when I went to rebuild the trans, I couldn't get the pump out cuz the back side of the pump was burned up and stuck in the moving parts it interfaces with. Basically, we didn't drive it much, and it was toasted...

I have heard about the splines getting beat out of the TC shell for that second input shaft... wonder if that's something?

The AOD in my Bronco got swapped for a ZF5 last summer, and I'm not looking back... so your T5 is a good idea.
 
Also, "fun" comment about the Bronco AOD... I bought the truck in Cali back in 2013, and the trans was awesome. Well, on the way back to MI, (still in CA) the motor died. I pulled the rear DS, put it on a rented tow dolly behind another Bronco and pulled it back to MI. When I got around to putting a new motor in it, the trans would lose prime every time you shut it off. During a cold start, the thick fluid and high idle would prime it, but on a hot restart, you had to hold the engine at 1500-2k for 10 seconds before it would do anything when you put it in gear. you could prime it in gear, but you just had to pay attention to make sure when it engaged, you didn't peel out.

Just an interesting issue that popped up inexplicably. The thing rode back on the dolly without a driveshaft in it, so it's not like I mucked up the trans from towing it...

Plus, they all seem to drain down the cooler and converter when they sit a while, so every winter when it was in storage, I had to put drain pans and cardboard under it to catch all the ATF that would puke out the dipstick o-ring, and shifter shaft when the pan level rises.
 
Picking up a used trans (lower miles than ours) this evening. The price is good even if it ends up needing a rebuild.

I still haven’t dug into ours to see if we did something stupid. Not enough hours in the day.
 
Definitely smoked something inside. Have to do a little bit of work to get the new/used unit in, but should be able to get most of it done by the end of the weekend.

The donor that we pulled the original drive train from had a stupid linkage setup for the TV Cable. Get things mixed up and you’re not operating the throttle Vave under acceleration.

We obviously had it hooked up wrong. I have a new Lokar cable & bracket this time.
 
landen300 said:
The proper way to do it is with pressure gauges, as you probably already know.
Click to expand...

Agree. I had a Lentech built AOD in my 84 Fox LTD (blown 331 stroker). I ran a copper line up near trans dipstick, and
put a permanent guage up there, I could check at idle, often.
 
While a misadjusted cable will cause damage over time I doubt it would cause a gear to randomly disappear.

Alot of trans diag starts with pressure checks but ultimately will end with pulling the valvebody or geartrain apart which to me is time better served getting it rebuilt.

I'd find a good AOD book and go through the diag of a missing third gear. Alot of things could cause it. Anything else is just guessing.

Agreed the only way to set the cable properly is with a gauge. Everything else will get you close but not exactly where it's supposed to be. With auto transmissions guessing is not good.
 
Ok, trans is in. I ended up getting a lokar tv cable because people want stupid prices for the oem stuff.

Directions on how to set up the lokar cable are not exactly clear.

Do you do the initial setup with the supplied gage block and then fine tune with the barrel adjuster?

We have a pressure gauge hooked in to the tv port. Checking at idle with everything warmed up.

We initially saw pressures as high as 50-60, but got it adjusted back down to 35, but getting it to return to zero when you pull the gage block out has been hit or miss.
 
Finally got a win.

I called lokar today and got the straight scoop on how to set up the tv cable.

Got everything dialed in tonight and was able to take it up and down the road a few times. It shifts through all the gears just fine. We may still do some fine tuning to get the shift points where we want them, but my $150.00 used trans seems to be working. It only needs to get through this season and then we are going to start collecting parts for a 5 speed swap.

Now to get some break in miles on the new engine.
 
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