I have a 1984 F-150 with a 5 liter and an automatic transmission with overdrive. It's always shifted perfectly with no issues at all but suddenly this morning it only has reverse and low. Both are firm when put into gear but once moving there's no shift to second. The fluid is up to level and not dirty. I'm at a loss.

 

Since you said overdrive, that would mean you have the AOD transmission. There's no modulator on an AOD. I would check and make sure the TV linkage did not pop off your throttle body. The linkage is held on by a plastic retaining bushing. If it did pop off, I would replace the bushing. You don't want this popping off while you are merging on the freeway because your tranny will get severely damaged.

If the transmission hasn't been serviced in a while, I would also drop the pan to replace the filter and you can get up to six quarts out. If you also drain the converter, you can get around 12 quarts out.

 

Throttle valve is stuck?
The TV cable adjustment method with a pressure gauge leaves a lot to be desired
Those AOD valve bodies do not like debris and will stick a valve if the fluid gets real dirty
If your fluid is nice and clean the valve might still be stuck or the cable housing sheath is sticking the cable possibly
Also, internal hard part or seal failure

 

Okay....I really appreciate your input but honestly some of your response is Greek to me. I was always a manual shift guy and I can fix most anything to do with one but I'm lost when it comes to automatics. Can you dumb it down a little more for me? Is the problem I'm looking for connected to the carburetor or somewhere near it or is it on the transmission itself? I've had the truck 14 years and in that time I've only put about 5,000 miles on it and it's always shifted like butter.

 

Thanks for your response. So the TV linkage is connected to the carburetor? I'm actually disabled so checking that will be the job of our 18 year old son. I've taught him about engines but I know very little about automatic transmissions. He's starting automotive school in May so hopefully we'll have our own mechanic in a couple of years.

 

You were correct. The linkage had popped off at the carburetor and once I put it back on it shifts great again. Thanks for your help!

 

Thanks! I was able to find the problem with your help. The linkage had come loose at the carburetor and I hooked it up temporarily (until I can find the parts to fix it permanently) just to make sure that's what it was and once again she's shifting like butter. Thanks for your quick reply and your great advice!
Doc

 

I would atleast order a couple of those bushings and replace it if you stay with the plastic setup. See below about the TSB. . If it popped off once it is worn, it likely will do it again. If it does it at the wrong time, your AOD will be toast.


There was a TSB issued for updating and replacing the plastic bushing but I believe those parts are discontinued from Ford.. However, you can get an updated metal bushing (aftermarket) to replace the plastic one and end the problem forever. I did my old AOD on my 87 Cougar several years ago when the parts were still available from Ford. It takes only a few minutes to replace and works with all AOD transmissions.

 

Looks like you vanished once you thought everything was good. . It will likely pop off again unless you do something about it. Hopefully, your tranny will survive this again, maybe not.

 

No I didn't vanish. I have serious health issues and am currently fighting pneumonia so I've been passed out in bed trying to avoid another hospital stay. I've been in the ICU 4 times in the past two years so sorry if I didn't immediately reply. I ordered a replacement but it won't be here until March 5th so I did a temporary fix with some washers and a hairpin clip but that did me in for a couple of days. I hope your day is great.