Vibration

[Repostyle]

Alright all you gear heads,

I can't seem to figure out what is causing a vibration in my car. Here's the scenario: I'm driving along picking up speed as it goes though all the gears in my AOD, 1st = fine, 2nd = fine, 3 = fine, 4th = vibration. I can do the same speed in 3rd without a vibration, or I can do the same RPM in 1,2,3rd without any problems, but once it goes into OD I get a noticeable vibration in the car like something is out of balance. I started noticing this about 3 weeks ago on my way home from work so I thought it might be a rough spot in the road. It's not the road, it will do it anywhere.

I just put new shocks and struts in when I put my lowering kit in, so does that either rule them out or put them as primary suspects for being defective?

Any ideas? I'm pretty sure the trans was rebuilt recently, but I'm not possitive since it was a repo and I don't know it's history. I've taken it to the tire shop and they're balanced so I'm out of ideas.

 

[Mike92GT]

Sounds like you may be having whats known as a "washboard shift" It's a real common problem with the AOD, and Ford has had several TSB's for it over the years. It is most often caused by old or burnt trans fluid, and a lot of times just changing the fluid will help. Adding another trans cooler helps sometimes too. Not sure, but I think the vibration occurs when the torque converter clutch engages, which is only when the trans is in OD.

 

[Repostyle]

I will give that a shot, any other ideas while I'm at it?

 

[Mike92GT]

Been awhile since I worked on a Fox with an AOD, if it has the small access hole in the bell of the trans, go ahead and drain the torque converter too. Just turn the engine by hand until you see the drain plug in the converter. That way you get almost all of the old fluid out.

 

[willys1]

are your u-joints good? I noticed you have gears,do you still have the stock drive shaft?