I have a 99 Expy, with the 5.4l and the 4R100 (AOD), and is 4WD. I believe the tranny is 4 speed? and I am having a weird shutter when it shifts between 3rd and 4th gear. Of course, now as I am typing this, I wonder if it is when it shift into over drive... Anyways, the shutter lasts about 2 or 3 seconds, and sound like you are driving over the center divide reflectors (if they were spaced about a foot apart). Any thoughts? Once it is ion gear it is fine, and everything else shifts smooth and seems fine.

 

It needs a complete trans fluid change. Either take it somewhere that can do a trans flush, or do it yourself with these instructions:

http://www.ford-trucks.com/article/i...nsmission.html

 

I had this happen to me also with my 4r100. Do a complete fluid and filter change. For this to work you will actully have to take it to a shope and have them hook it up to a machine that will flush all the old fluid out; just dropping the pan will only get about 1/3 of the fluid.

 

You may not have to take it to a shop.
My 97 4.6 with the same transmission started
to do the SAME THING after I bought it with
82K miles.
I could actually get it to shutter under light throttle
up a small incline 1 second shutter 4 sec fine 1 sec
shutter and so on as the od was shifting on and off.

I made the mistake of going to ford for
a flush and filter change using MERCON V.
What they did I could do at home in 20 minutes.

Drop the pan
change filter screen.
seal up pan.
add 6 quarts Valvoline MAXLIFE.
charge me $129 +T

However, it was enough to add enough Mer V
to fix the problem completely as the new friction
modifiers did their job.
In the spring I will add another 6 quarts.

You must change fluid EVERY 30k mi, 15K if
you tow. Use ONLY MER V.
.

 

Read my post above. There is a procedure to change all of the fluid at home just like the shops with the machine.

 

Yes Mark I want to do the whole change but I figured that
a pull of the fluid up the dipstick with an evacuator can be
done in no time with no removal of the pan. Even though I won't have
a complete flush more and more new fluid will be added.

I think once it warms up It may be time to do the
whole job plus the Transfer Case and the rear end.

 

A complete fluid replacement has been recommended as the RIGHT way to fix this problem by an experienced transmission technician.

 

I still prefer standard DexIII/mercon instead of merconV in the 4r100's. Add a bottle of red lube guard with it if you are concerned about just using inexpensive fluid.
Alan

 

your transmission isnt suddering when it shifts into overdrive its your lock up torque converter just add a tube of anti shudder and your problem should go away if your oil is red dont change it.

 

your transmission isnt suddering when it shifts into overdrive its your lock up torque converter just add a tube of anti shudder and your problem should go away if your oil is red dont change it.

 

My 2000 4wd Expy is doing very similar things.... My oil is red/pink and doesnt smell burned....

When cruising at 50-60 70...you get the picture..... If I add a little throttle I get a vibe that I can feel in the gas pedal.

Also...now that its colder out, it takes a while to shift to 3rd 4th at low speeds ie. city driving.

Do I also need a tube O anti shudder? Is this found at NAPA or Autozone?

Thanks for any info...

 

Torque converter shudder. Change the trans fluid.

That's normal operation for cold weather. The shifts are delayed to help the engine warm up faster.

NO!!!!!!!!!!!

 

Thanks for responding so quickly. I will get the fliud changed.