[HSLDS]

OK - a problem for you Ford mechanics/techs. I know you are out there and have helped others, so I figured I might pick your minds as well...

My 2004 Ford Expedition (95,000 miles) has developed a transmission 'bump.' Engine is 5.4L with 4 speed auto trans (NAAO AODEW/4R) with 3.73 limited slip rear.

The rear was re-built under warranty (about 5,000 miles) as a known issue.

Recently the car makes a noticeable bump when down-shifting on acceleration. It is most noticeable at about 55/60 mph. I've felt it once or twice when shifting into reverse as well.

I suspect U-joints (no vibration present), but figured you might know something I do not... Will crawl under the car tomorrow for a look-see.

In advance, thank you all.

David D

 

[Remstar311]

I would probably check the transmission mounts, motor mounts, and carrier bearing assembly if it has one. I do suspect that they would be heard more often from a start. Might as well check the exhaust hangers too.

I wouldn't think the U joints but might as well check them while your under there.

 

[Shooting Jack]

I know you will think I am way out in left field but I had a very similar feel/sound on two of my fords. It turned out to be a coil going bad, it gradually got worse and I checked for codes and that's when I found out no. 4 was breaking down. Before you say no way, have it checked as you can get it checked at some parts places for free. Jackie B.

 

[Quack Shot]

Might be a splined slip yoke. They have a tendency to wear and when they do, they "clunk" a little on acceleration and decel. I think there may have been a TSB on that at some time. I just don't remember offhand if the 04 had the slip yoke or not. Hard to pinpoint without actually hearing and feeling it.

I would also look for any contact between rubber bumpers and any other suspension components. Worn suspension members/bushings can also make noise.

 

[rumseyplum]

Had a 94 F-150 that developed a "bump and grind" when the transmission shifted up or down...my wrench friend suggested changing transmission oil and having filters in tranny cleaned or replaced...took it to the shop and had that done, around a $100 as I recall...worked perfectly for the next 100,000 miles...
Happy Motoring...

 

[Tron]

If the U joints are OK, pack the slip yoke with blue teflon grease and that should fix it.

 

[HSLDS]

Quack Shot & Tron,

Thanks - I suspect that it is the slip joint...

No error codes, U-joints look OK, as do the CV joints... Motor & trans mounts look OK too.

David D

 

[Tron]

I would remove the drive shaft and inspect the U joints closely. They make look OK, but if you drop the shaft, you can then check for binding much easier.

 

[HSLDS]

Tron,

Looks like I have to pull the shaft to grease the splines anyway, so I'll go over them then (got good at this - had a Jeep CJ-5 that used to 'eat' U-joints).

THANKS