99' F150 Shutters OD Shift 45-55 mph

[lots of luck]

Anyone experience this with there own F150? I just had it happen a little while ago while driving home from St. Cloud and I have just started my research online. Seems like this happens occasionally from my initial reading, but I have yet to fully research the probable diagnosis and method of correction. Initial comments talk about worn out transmission fluid corrected by a flush and fluid replacement.

As soon as the transmission shifts into OD at 45 m.p.h. it starts to shutter until 55 m.p.h. Accelerating past 55 m.p.h. the shutter subsides. Only happens during acceleration and does not happen during deceleration. Obviously requires a load. Babied it home.

99' 5.4 +/- 135k miles automatic transmission obviously

Anyone experience this before?

[Shack]

Yep, flush the fluid.

Maybe a good idea to have them drop and clean the pan also.

When was the last flush done on your truck?

[Northlander]

Same thing here. Rear seals were bad and Im getting a flush. Mines at 40 mph and usually going up hill or pulling the boat.

[rmrakt]

Don't rule out an engine missfire....I had the same symptoms on my old Explorer that I had (after a recent transmission rebuild) brought it back to the tranny shop and found a plug wire was resistive. Failed under load (when it shifted into OD 45-55mph).

Could be your tranny but something else to check?

[upnorth]

Personally I would drop the pan, change the filter and refill the transmission. If the filter is plugged or getting plugged a flush will not help and may make things worse. That came directly from the guy who rebuilt the trans in my Ranger a few years back after a flush.

[Shack]

Yep, that could cause this also!

[redtrucks]

You describe the exact same problem that I had in my 01 Supercrew. I had a bad COP (coil over plug). The pickup had 75,000 miles on it. I ended up replacing all of the COPs and sparkplugs. I found the COPs on a online auction, 8 brand new ones for the price of one from the Ford Dealership. 20,000 miles latter and no issues. If the truck has not had the plugs replaced yet its due. Heard alot of horror stories on the replacing the plugs on 5.4 but it really wasn't that bad. With a cold engine it took about two hours start to finish.

[lots of luck]

Don't rule out an engine missfire....I had the same symptoms on my old Explorer that I had (after a recent transmission rebuild) brought it back to the tranny shop and found a plug wire was resistive. Failed under load (when it shifted into OD 45-55mph).

Could be your tranny but something else to check?

I am researching the Coil Pack scenario right now. Without touching the truck yet I have a few individuals that have the exact same symptoms and it ended up being a faulty coil pack on one of the plugs. I am going to do some research tonight. Anyone know if there is a test I could perform on a coil pack? I will keep everyone posted.

[lots of luck]

You describe the exact same problem that I had in my 01 Supercrew. I had a bad COP (coil over plug). The pickup had 75,000 miles on it. I ended up replacing all of the COPs and sparkplugs. I found the COPs on a online auction, 8 brand new ones for the price of one from the Ford Dealership. 20,000 miles latter and no issues. If the truck has not had the plugs replaced yet its due. Heard alot of horror stories on the replacing the plugs on 5.4 but it really wasn't that bad. With a cold engine it took about two hours start to finish.

Thanks for the heads up redtrucks.

[theoilman]

Transmission shudder is a plaguing problem with many Dodge and Ford (but few GM) transmissions - due to aging and poor quality fluids.

Relatively simple fix, change the fluid. I definitely recommend drop the pan, clean it and change the filter. Also best if you flush the converter too.

Fairly simple but potentially sloppy procedure to change all the oil yourself.

First drop the pan, clean, change the filter and replace. Refill the pan quantity. Do NOT start the engine yet!

Second to change the converter fluid, disconnect a cooler line at the most convenient location and slip a piece of tubing on both sides (you will probably need some type of adapter). I prefer clear tubing available at any home center or hardware store. Have your assistant crank the engine - oil will come out one tube (I am yet to find an accurate book to tell me which way the flow goes for various vehicles). Fill down the dipstick tube while oil is coming out. After about 5-6 quarts you should see a fluid color change to the new oil. Shut off the engine immediately. Reconnect the cooler lines, check the fluid level, test drive and then recheck.

You will need about 1 or 2 quarts more than total fill. Most truck with gasoline engines around 12 to 14 quarts, diesel engines may be considerably more, most 4wd 1 or 2 more. AMSOIL's product application guide will give both the pan and total quantity for most vehicles.

Of course I recommend the best fluid, AMSOIL Universal Synthetic ATF - GM Dex including VI, Mercon V and SP, Dodge ATF+4, Toyota T-IV, Nissan N, G, K, Honda Z1 and more (this link has the complete list). Also a pdf of the change procedure is available here.

[Scott K]

I would bet it is a miss fire!

[redtrucks]

One thing my F150 didn't do when I had a shutter was the service engine light never came on. I would work on the COPs before I would change the trans fluid.

[rmrakt]

lots of luck,

Can you post your findings here? May help someone else someday.

Thanks.