Hey all,

1995 F150, 5.0, 4 speed OD automatic, 4 WD with auto hubs.

Truck has a on/off/on/off shudder while at slow, constant speed - say 25-35 MPH. It shudders for maybe 2 seconds, then stops for 2 seconds, then shudders again for 2, then stops, etc-etc. I disengage OD with the button at the end of the shift lever but it still does it. If I let up on the throttle (coasting) it stops and if I toe into the throttle - thereby forcing a downshift, it stops.

Any ideas?

Dan

 

Check the U-joints first, sometimes you have to take the driveshaft out, and move the U-joints all around to see if they have any stiff spots or play. If those are bad replace them. If all else fails take it to a trans shop, might be internal in the trans.

 

I considered the u-joints, but am inclined to believe if the UJ's are bad then it would vibrate/shudder much more often.

The 25-35 MPH, part throttle range seems to be the only time it does it.

Dan

 

Do you have the updated 1-2 piston?
The old one will score and do this.
A little scotch bright and an updated piston will fix it.
Just drop the pan, pop the old one out and scotch bright it then put the new one in.
Good time to change the filter and fluid.

 

Bill,

No idea if it has the updated 1-2 piston. Bought the truck used 6 months ago with only 31K on the clock.

Gotta ask, how does the 1-2 piston come into play in this scenario when the trans is already in 3rd, 4th, or 4th + OD?

Dan

 

check u-joints.

did you change fluid in trans?

 

QL2,

To the best of my knowledge the fluid has never been changed. Looks nice and red, clear, and smells as nice as transmission fluid can.

Dan

 

Do you think you are in "3rd, 4th, or 4th + OD" at "25-35 MPH"?

 

Absolutely Bill.

The truck has 30" tires installed but is otherwise bone stock, right down the the 3.55 gears. The speedo is a little off with the 30's, so maybe the MPH range is more like 30-40.

Under light throttle I can feel, and watch via the tach, it shift from 1st, to 2nd, 3rd, and then 4th, and then usual converter lock up.

There is one stretch of road where I can always, without fail, reproduce the symptoms. The road is in my neighborhood and posted speed limit is 25. One direction has a very slight incline, other way is down hill of course. About 1/4, or 1/3rd mile long. Start from a dead stop at the bottom, watch/feel it run through all the gears to an indicated 25/30 MPH.

It definately is not staying in 1st, 2nd, or holding in 3rd at that speed, but I'll test it again on my way home this evening.

Dan

 

the fluid is 12 years old and should be changed.

at 35 you may be in overdrive but not under that.

 

Flush the trans with * shudder protection * trans fluid . Dont drop the pan .... flush it and get all the fluid changed .

I beleive on the AODE the converter locks in second if I remember right .

 

'Stang -

"Shudder Protection"? An additive is it?

 

naww man ..... look on the trans fluid at the parts store . Some trans fluids have * shudder protection * advertised on the bottle ..... its already mixed into the quart of trans fluid .

Shuddering is a Common problem thats usually cured with a flush .

You can flush it yourself if you want . Im too tired to type how to . I posted it last week tho to another dude .

 

Thanks Stang.

I have not owned an automatic equipped vehicle for over 20 years - I think now I remember why. I can pretty much guess how to flush it; take loose the trans cooler line into the radiator and have it empty into a jug, then start the engine and let the trans pump most of the fluid out.

I'm sure I can find the correct type fluid to use in one of my factory manuals, but do you have a specific brand in mind?

Dan

 

My fathers 83 F150 5.0 AOD with 3.55LS was used as a daily driver and travel trailer hauler after he retired. The travel trailer wieghed 5000lb and it traveled from Mass to Fla. My father would have the trans fluid changed once a year. When I had the truck I installed a pan with a drain plug to make the job easier. The truck lasted until 220k miles and the trans was still ok and shifted very well. I did install an aux cooler and the truck was ordered with a towing package.
I would first change the fluid and filter and do the upgrade on the piston before doing the flush.
regards
rikard