Ford's Finest....

Sam from WA · Feb 19, 2011

Hey guys, my trusty ol' 89 F150 isn't so trusty anymore, now it shakes really bad in overdrive. It's got the AOD trans in it, and it only shakes when pulling hills and its well warmed up/hot. It will shake on relatively flat ground too, but only after its been warmed up driving around and up a hill (even slight little grades do it). Once warmed up, it won't even move out of its own shadow on the freeway doing about 65-70. It HAS to downshift out of overdrive before the engine will make enough power to accelerate. Before, I could go from about 60 to 75-80 in overdrive no problem whatsoever and not have to downshift. I'm thinking the overdrive band/clutch is going south on me. It still shifts up through all the gears OK and drives fine, even hot, but has problems with overdrive. I can drive in third all the time and have no problems, but it is kinda hard on the fuel economy. Is there something easy I could try first without overhauling the trans? I don't really want to overhaul it if I don't have to

GordoSD · Feb 19, 2011

How many miles on that tranny?

Sam from WA · Feb 19, 2011

97,000 miles. All original. The truck sat for nearly 15 years after my grandpa died in 1993.

GordoSD · Feb 19, 2011

Sounds like at least the TC is toast. You have a $2500 truck that needs $1200 repair.

Sam from WA · Feb 19, 2011

But here's the catch, that transmission does NOT have a lockup converter. There are two input shafts. First and second gears drive off the converter turbine, while third and overdrive are driven directly off the flex plate. Hence the two input shafts. So basically, third and over are driven like having the converter locked. And it would make sense that the overdrive clutch/band is going out because its the one that gets the most use. Or at least that's my thought?

Gun guru · Feb 19, 2011

I would change the trans fluid and also unbolt the main valve body and accumulator body and flush them both with CLEAN trans fluid in a clean 5 gallon bucket and get all the sludge/silt/crap off. And change the trans filter too.

Get a basic schematic of the transmission before hand.
That is the first thing I would do.

Kruse · Feb 19, 2011

You are ABSOLUTELY sure that it is a tranny problem and not a miss from a bad wire or spark plug?
(Gotta rule out the obvious)

Sam from WA · Feb 19, 2011

I'm pretty sure its not a misfire, I just changed the cap, rotor, plugs and wires all about 5,000 miles ago. That was about mid-November. I have not noticed any misfires whatsoever. It only shakes in overdrive after its warm.

GordoSD · Feb 19, 2011

Maybe go to some way oversize 15 inch tires on the rear and stay in 3rd gear?

Goose · Feb 19, 2011

I had an Aerostar van act like that once. It would buck and vibrate when pulling up a hill in OD. After it kicked out of OD into 3rd, it ran fine.

I babied it 1200 miles home from Washington DC that way. Didn't want to go into it on the road 'cause I was afraid I'd wind up worse off.

Poked around under the hood after we got home, and found one plug wire partway off. That cured it.

chucksoliver77 · Feb 19, 2011

sam, when is the last time you changed the fuel filter. how is the fuel pump? just some thoughts, chuck

Sam from WA · Feb 19, 2011

Fuel filter is less than a month old. I replaced it
because the one in there was probably factory
original. Fuel pump seems to be OK. But now that
you mention it, I wonder if there couldn't be some
varnish crap left in it from sitting so much? But
it seems to run fine without any misfires or real
lack of power. It just seems like something is
slipping/dragging in the trans, it does kind of
pulse when in overdrive on FLAT ground or very
slight down grades in overdrive only.

Sam from WA · Feb 19, 2011

Update: The trans fluid is a dark red, almost kind of maroon color. Doesn't smell burned at all, but does seem to have a small amount of grit in it. This is from the dipstick. Trans fluid level OK.

IH2444 · Feb 19, 2011

Does it have coil packs in it?

Wifes Lincoln with a 4.6 had similar problems, everyone said the coil packs do not go bad. I did plugs, wires, fuel pump finally and said to heck with and put a coil pack in it and fixed it.

Wish I had followed my instinct and not listened to the "experts".

d9gdon · Feb 19, 2011

I think you've simply got a miss in your engine causing the whole problem instead of it being the transmission. You say you changed the plugs and wires about 5000 miles ago? That'd be the first place I'd look.

Sam from WA · Feb 19, 2011

Plugs and wires are all tight and dry, unless
there's a bad wire. But I kinda doubt that. The
cap, rotor, and wires are all NAPA parts, the
wires are their premium premade wires. Plugs are
Autolite 25's, which is what I took out, so those
are the same as original. Timing is dead on set
to factory spec as specified on the air cleaner
cover and in the book. I had to put a new
ignition module on at about 70,000 miles, that
came from CarQuest. Its running better now than
it was when I first got the truck, before it
really did misfire and the transmission or even
the whole truck never did shake or vibrate like it
does now. Universal joints are both good and
tight, I even greased them up yesterday while I
was tinkering with my lawn mower and had my grease
gun out.

Detmurds · Feb 20, 2011

Hey my Washington Brutha! Take it to a Tranny shop and tell them to tune up the tranny. I hope you never took it to a Jiffy Lube-like oil change joint and had the tranny "flushed",....they destroy trannys! I say this in the event it is about your transmission?

Sam from WA · Feb 20, 2011

As far as I know, jiffy lube kinda guys have never
touched the trans. At least not in the time I've
had the truck. I've done all the work on it myself.
And I kinda plan to keep it that way, except for the
trans if I do get it rebuilt. But at this point, I
think if the trans is the problem, I'm gonna junk
the transmission and put in a Gearstar AOD Level 2
anyways.

Kellyc · Feb 20, 2011

"everyone said the coil packs do not go bad"
They Lie dont they? I drove a 150 at work with those coil packs. In 3 years I had it in 4 times replacing coil packs.
Although I had the last of our 4 wheel drives and they could get it from me after prying it from my cold dead hands.
They kept trying to get me to turn it in for a new one.
Funny, Even with 250,000 mi on it. Wore out seats and wired shut compartment doors. After a snow storm I still made it to all my stops and still had time to pull out a few 2wd F150's. Ofcourse I had to make a few of their stops too.

davejoe · Feb 20, 2011

Hello, recheck the plug wires for #7 & 8 plugs. If they are run together in too long of a parallel you can get an inductive crossfire. Your problem was actually quite common when these trucks were new. Dave

jcarbs · Feb 20, 2011

Sparkplug wire routing.
I once had the exact same issue on a 88 302 F-150.

TSB: 94410 FEB 94 Spark Plug Wire - Miss/Buck/Spark Knock

Also see this post
http://www.ford-trucks.com/forums/279050-92-f-150-302-efi-e4od-tranny.html

John

d9gdon · Feb 20, 2011

Still think you've got a dead miss. Recheck the plug wires to make sure you didn't cross a couple by checking them against the firing order. Also, did you gap those plugs and if so what was the gap?

molinebob · Feb 20, 2011

i believe that model has two fuel pumps in it, one is in the tank and there is one on the frame rail, dads had that issue too, he changed the pump on the frame rail and it cured his problem, just something else to check?...Bob

chucksoliver77 · Feb 20, 2011

sam, maybe your e-brake is seized, that could cause a pretty good vibration when they get hot.

K. Peters · Feb 20, 2011

I had an '89 F150 5.0L AOD trans just like you describe and encountered the same symtems two different times. The first time it ended up being a half broken badly corroded wire going into the fuel pump relay. The second time it turned out to be the TFI module on the side of the distributor, heat is their biggest enemy, if I remember correctly their is some special grease that must be applied to the back of it before you bolt it on the distributor. Just my experience hope it helps.

Kris Golden · Feb 20, 2011

My mother had a '95 [i think] Cougar with a 4.6 and AOD trans and it started to shake badly. She took it to a local mechanic and he checked everything over thinking it was a bent driveshaft, bad U joint or out of balance wheel. After he couldn't find anything wrong he called the local Ford dealer they told him it needed a tranny flush. The mechanic didn't have a flusher so he sent the car to the dealer and they flushed the trans. Problem solved and the tranny worked perfect for several years until she traded it off. I wouldn't trust an oil change "expert" to flush a tranny and I wouldn't just change the fluid/filter without a flush - take it to the dealer.

Bryan inIowa · Feb 20, 2011

Verify that you do not have an ignition missfire ! shop with an ignition scope will confirm or deny it . Better spend 60 bucks there than 1200 at the tranny shop . Trans shop down the street sends me a TON of cars with engine trouble instead of susppected tranny problems

trucker 40 · Feb 20, 2011

Since you don't think its a miss,maybe you should change the oil and filter in the transmission.If it sat for 15 years it might have some water in it.I'm not sure how they flush a transmission at Ford,but that sounds like the right thing to do.
You could probably get a transmission from a junkyard that hasn't set for 15 years.That's if you are sure its the transmission.You might want to check on a transmission being available before you get it flushed out.

Anonymous-0 · Feb 20, 2011

97k miles and it sat for so long - I would not do a flush but a fluid exchange. Flushing will likely cause particles to comes loose and seals to leak. Mechanics I know recommend the fluid exchange which cleans far more fluid than if you just drop the pan.

Sam from WA · Feb 20, 2011

This is what makes me suspect a transmission problem: it ONLY shakes at about 70mph, in overdrive. If I let it run at 60-65 it will NOT shake. I can get it to shift into third at 25 and not shift out, back to second. It does NOT shake, vibrate, or anything. Just pulls itself right along and picks up speed like a champ. I have serviced the transmission, at about 80,000 miles. When it does smooth out and quit shaking on flat ground or slight down grades, I can feel a "pulsing". I just changed the muffler and gutted out the cat, but even before that I noticed my fuel economy really falling off. Yesterday, I couldn't even drive for two hours without burning all of 17 gallons of fuel, where it used to go five hours on 10 gallons. This is all highway driving. This is why I suspect a transmission problem. Does that make sense?

John M · Feb 20, 2011

Pull the codes. If its a misfire, itll show up in the codes. You dont need a code reader, instruction are on the net.

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