I have a 1999 EB awd 5.4. I have a bad shudder only when I take off. It does not shudder at any other speeds just take off. I have changed all the fluids in the truck with the correct specs. Any ideas what I should do next.

 

Does it shudder when you are stopping also? What does the shudder feel like? Is it more of a clunk? If it is a shudder, how does it idle?

 

Nothing while stopping. It idles fine. Not a clunk but more of like a vibration grind type feeling.

 

Ok, well i guess we can rull out the bad COP issue.

Vibration grind feeling? Could possibly be bad u-joints. Is the vibration constant if you hold it at a certain low speed? If so, get to this speed and put it in neutral and see if it is still there. This will help determine if its drivetrain related or something else.

 

All fluids include rear differential and transmission ? could the emergency brake be hanging up ?

 

Nothing in neutral. Only time I feel it is if I hit the gas when taking off from a stop. It only lasts for a few seconds and then stops

 

It could be u-joints in their way out, but that is normally a clunk feel. Could be that the slip yolk needs to be re-greased (common on these trucks).

scholzee brings up a good point with the differential fluid. Does it feel like its in the front or rear of the truck?

Vibrations / grinds are hard to pinpoint on the internet. Might want to just take it in and get it diagnosed, then go from there. Deffinatly sounds like its drivetrain related and only occurs under load.

 

I mentioned the rear differetial fluid because most EB's came with the limited slip rear end with clutch packs. When the fluid gets old and dirty the clutches can chatter, but that usually happens when turning or at least should be worse when turning when the wheels are trying to rotate at different speeds and the clutches should slip. I guess they could also chatter some in a straight line. You need to look at the axle code on the drivers door label and see if the truck has a limited slip rear end, if it does not you can disregard chatter from these clutches as it will not have them. Do a search for LS or xle codes on this site and you will find much info.

 

If you have a LS rear diff and the fluid was changed, they probably forgot the friction modifier additive.

About $6 and will usually fix the rear diff shudder.

Steve

 

I did all the fluids myself and made sure I did not forget to add. So its not that I wish it was that would be the easy fix.

 

when you changed the tranny what did you use mercon or mercon v?

 

The reoccuring shudder on my 99 4WD, like you describe, has always been cured by changing out the A4WD transfer case fluid ~ 2 qts of the correct trans fluid. Frequency is about every 15K miles with a trans changeout every 30K along with the transfer case. The transfer case changeout is twice as often as the manual says but it eliminates the problem. Good luck.

 

I agree change the transfercase fluid. It fixed mine.I also have a 99eb.

 

I have the same shudder from a stop. Nothing in turns, etc., so I don't think it's clutch packs or additives. I will try the transfer case fluid change, but there is also another issue which surfaced at about the same time...

At almost exactly 70mph, there is a serious rumbling vibration from the front end. The first thing I did was get the tires balanced and rotated, but it didn't change a thing. It seems to be getting worse, and I'm worried. It feels like tires that are seriously out of balance, but there isn't any movement in the steering wheel. Just moaning, rumbling vibration. Could this be related to the transfer case, CV joints (never replaced), or can this be the front diff spinning like crazy? There is no pulling in either direction. Brakes are perfect, no warping in the rotors. State of the wheel bearings is unknown, but I would think that if those were bad, it wouldn't happen at exactly 70.
Truck is a 99 Expy with 104k miles. Any help appreciated.

 

I had [have] the same shudder with my 2002 Navigator. There is a TSB calling for new rear lower control arms, which changes the pinion angle a bit, which is supposed to reduce the vibration.

My dealer replaced the drive shaft (with u-joints), the TC fluid, and the lower control arms (based on the TSB). The rear end fluid was also changed at some point. The vibration is better, but I still feel it. The only thing that made the slight difference was the LCA. I finally just gave up and got use to it. It's only on take off, more obvious with a slight uphill grade.

What I feel is definitely driveline and not engine. I still believe that it has something to do with the pinion angle.