Slight Acceleration Shudder

[Mediamonkey11]

Hey all,

I've got a strange little happening going on with my Expy. ALWAYS between 5 and 9mph during acceleration I'll get a slight shudder/wiggle from what seems like the rear end. I just changed the trans fluid, installed a cooler, and a remote filter kit with in-dash temp gauge which did not seem to make any difference at all other than a slight increase in smoothness of shifts (old oil was still very red, just slightly darker than new).

I filled it with Castrol Transmax Mercon V just for reference.

What does this sound like, trans mount, slip yolk, u-joint?

BTW, it does it regardless of turning or going straight, and regardless of how hard I accelerate.

Thanks guys!

 

[Mediamonkey11]

Uh oh, no ideas might be bad! Lol

 

[grayGT10]

I have the exact same thing on my 02 with 96k on it. I also had it on a previous 01. I too would like to know what this is. It does not affect the normal drivability but is driving me crazy! I mentioned it to a technician at a Ford dealer. He stated "it's normal, nothing to worry about". I'm thinking it's not normal. Anyone have any insight?

 

[grayGT10]

As a side note, I do not feel the shudder when I accelerate in reverse.

 

[KWT2000]

is it strait line acceleration? or only when turning doesnt need to be much of a turn

if it is when turning you most likely have a limited slip rear diff and it doesnt have enough friction modifier in it,

 

[BakerEdition]

I have the same in my 2000 5.4, been there since 77k when I bought it and still there 3 years later with 105k....I had this happen in a car one time...it was the U-Joints. I looked at mine last year and grabbed the drive shaft to see if they were loose..but nothing...So I thought I would drop the shaft and pivot them and see if they were binding....but them stupid star headed bolts wouldn't break loose and I didn't want to snap them off...but its in the back of my mind to take it somewhere and have then replaced just because of age and mileage...but i would put in a good joint like a "spicer"

mine does it on acceleration going straight and it don't do it all the time...sometimes I notice it more than others.

 

[KWT2000]

thinking this thru 99 and up are AWD wonder if it could be viscous coupler in the T case?

 

[BakerEdition]

I think they had the problem with the Oldsmobile Bravda..

 

[Mediamonkey11]

It happens when turning or when going straight, it's a little worse the harder you accelerate, the more I think of it. I'll likely change the diff and tcase oils, what do they take? Yes I have limited slip.

 

[KWT2000]

the Tcase takes ATF about 3 qts, the rear takes 85/90 plus the friction modifier, castrol makes a synthetic with the modifier in it for $10 a qt, i got mine from oriley