COMET CENTRAL

Im having trouble with my AOD not having any movement, seemingly randomly, and working fine other times. Long winded post, but im trying to be as detailed as possible.

Story goes, I bought this trans used. Fellow said it came out of an 88 F150 with a 5.0L. It was marked 168K (Kilometers, roughly 100k miles) and he said the truck was wrecked and thats why it was pulled. I got the flywheel and block seperator plate with the trans all for a couple hundred bucks.

When I bolted the trans up to the engine, I made sure the torque converter was all the way engaged. The trans bolted all the way up to the block without binding and the torque converter was not jammed into the flex plate, so I do not believe that Ive just missed the pump engagement (though when the rain stops im gonna go double check).

When I was first running the engine, I had no shift linkage, cooler lines, or driveshaft. So for the first few runs of the engine, I had the trans in park, the cooler lines just looped, a driveshaft yoke stuck in the end of the trans, and enough fluid to show on the dipstick. It was run maybe a total of 45 minutes like this. When I made the cooler lines and shift linkage, and got the driveshaft in, I fired it up and all was well. In topping up the fluid, i needed another quart or so, so I shut the car off and dug out another quart. Fired it up and topped it off, and then no engagement at all. Tried a few things with no luck. I later tried some lucas stop slip just for fun with no luck.

So I pulled the pan, changed the filter and cleaned out all the lucas that had settled in the pan. The fluid looked ok coming out and there didnt seem to be an abnormal amount of clutch material in the pan or anything. Cleaned everything and put it back together, filled it up, and I had engagement again. Everything worked. I was out of ATF and still a couple quarts low, so I shut the car off and left it a few days. Few days go by, I pick up some more ATF and tried it, now when running the dipstick shows over full, when a few days ago it showed low still, and I have no engagement at all. If I start it in gear with the rear end jacked up, It will spin a wheel for a couple seconds with no real force, and then thats it. Its almost like the pump isnt pumping, but that doesnt explain why it works sometimes and not other times.

Hoping someone with more experience than me with the AOD trans can chime in. My goal is to exhaust all possibilities before I pull the trans and have it rebuilt.

Do you have TV-Valve linkage and is it adjusted?

Are you sure you have it shifted into drive and yes you have to have the TV-valve adjusted to get forward motion. You hook up a pressure switch to the transmission and you adjust the TV-cable to get 35lbs of pressure at your idle speed. This is very important or you will ruin the transmission clutches.
tom

The TV cable is connected. It's got the stock truck cable installed, with the stock bracket at the trans end and a custom bracket at the carb. I followed the adjustment procedure on the Mitchell on demand program from work, which was just to take the slack out of the cable.

Sounds like the converter is draining back which would cause the trans to be over full when sitting for a while. It should,however,engage when the converter fills back up. If you think the trans is in good condition otherwise you might try this...
http://www.transmissionpartsusa.com/Shi ... 027930.htm
This kit is fairly difficult to install but requires no special tools. Follow the directions closely. If the throttle valve was ever way out of adjustment or disconnected,odds are it's time for a rebuild.

I've done 2 trans rebuilds when doing my automotive apprenticeship, so I have some confidence in doing automatic trans work, and there's a couple good videos on AOD rebuilds on YouTube.

Converter drainback did run through my head but I dismissed it as I thought that was mainly a C4/C6 thing, but I guess it could happen to any automatic transmission.

I'll have to let it sit and idle for a few minutes to see if it fills up and starts grabbing. The problem is the car is loud and the neighbors are pissy, so I try not to run it too long at any given time. I'll have to rig up some additional mufflers to testing purposes.

Since I've had it the TV cable has been hooked up. It was hooked up when I bought the trans, and the stock truck cable has a little sleeve on the throttle body end, as to keep the cable from retracting to far. So here's hoping it hasn't been run without that hooked up...

ON my wife's 93LX 5.0 mustang AOD,,that little plastic part on the throttle body that pulls the cables when you press on the gas pedal broke,,causeing the correct pressure to be right,,,she never told me the transmission wasn't shifting correctly,,,the first thing to go was Overdrive,,it's been so long ago,I think it finaly got to not wanting to go into gear,,,she finaly told me about it when I had to go rescue her and the car,,,in the end the complete transmission had to come out and be rebuilt and verter was replaced as well,,,we bought this car new and today we still have it,,,one other time she came in and told me it was not shifting right,,,I went to the ford place and bought a couple of those plastic hook ups and changed it ,as it was broke again,,I carry a spare in the consol,,,seems like heat makes them brittle and they just snap,,,I can't recall the correct name of that little part,,but it has to be there in order for the trans to get it's right pressure ...this may help firgue it out it may not....good luck pop

HEY,I just remembered this after posting the above post,,,,,,while driveing my 94 f150 5.0 AOD,,at random it would go into nuetral,let off go back in gear,,going up a hill flat ground or even pulling a trailer it would happen,,,,my transmission friend dropped the pan and found a broken spring,,,I think he told me he dropped the valve body also,,this spring is about the same dia and length of my index finger,,,he replaced that spring only...that fixed it,,still have and drive that truck today,,,it's perfect,,,still drive it regularly,,in fact it rolled over on 87,000 mi last week,,when it 1st messed up it had less then 30,000 miles on it,,,,it is the same black pu I pulled my comet to the PF gathering,,,pop

I'm sure you know this but the TV adjustment is not like the kick down on a C6. The Transgo kit I mentioned has a really good seat of the pants TV adjustment procedure in the instructions. For a complete rebuild,about the only special tools you will need is a set of seal protectors and a drawer full of snap ring pliers...and maybe bushing drivers if you need to go that far.

So I had a chance to play with it today after work. I think I'm fighting both converter drainback and TV cable adjustment.

I finished my exhaust so it wasn't so loud in an attempt to keep the neighbor happy. Then I fired it up and idled it. After 5 minutes or so I still wasn't getting anything, then for giggles I unhooked the TV cable from the carb, pulled it another 1/8 inch or so and clamped it with vice grips. Then it sucked in a bunch of fluid and I had a transmission again.

I also added not quite 3 quarts of ATF to bring it up to full while idling in park. It was at that point the neighbor told me to knock it off. So I'm not sure if the TV cable was mis adjusted or TV pressure was just low because of low fluid. Probably a bit of both.

I'm close to being roadworthy too. So I won't know the condition of the rest of the trans till then. However I'm hoping that eventually driving it around/letting fluid flow and changing the fluid once again will help unstick whatever is letting the torque converter drain back...