98 Expedition Trans Bypass Whining - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

bmxracr96 · 05-20-2009, 19:58

Guys i have a 1998 Expy 5.4 XLT. 133k

Transmission was nice and quiet til I had a shop flush my transmission. Very shortly afterI started to have a whine. Its constant while in reverse, and for the first few seconds accelerating forward. While on the lift we put it in reverse and you can feel the vibration in the CBV on the side of the transmission. Figured it was a bad cooler bypass so we replaced the bypass valve with a ford OE one. No change.

I have searched over and over have not read anything about these being noisy. Til this day it continues to make the whining sound, the fluid is new, fluid is full, no codes, no shifting problems or anything else.

What could be causing this noise? Is this normal? I havnt heard any other expedition make the noise.

bmxracr96 · 05-21-2009, 00:01

Eh, so i guess noone has seen this...

bmxracr96 · 05-21-2009, 19:35

Has this been discussed before and I'm being ignored??? I searched and couldn't find anything relating to my noise.

or

(Which I find it hard to beleive) That noone has heard of this......

**jwko** · 05-21-2009, 19:46

I don't think you are being ignored, just not the right person has come along yet that can help. I did a search on the forum and found no threads that match your problem.

Just hang in there and I'm sure someone will come around

thundercougar · 05-21-2009, 20:05

is this the first time its had a flush? there is an on going debate that a vehicle with over 100xxx miles on it with no prior flush,the flush will cause all kinds of problems.some places wont even do them if they have never been flushed and the vehicle has 100xx plus miles.i had a shop refuse to do mine.went to another place thinking the guy didnt want to bother with me.it was a busy place.had a flush done.i noticed slipping on mine right away.from my research,when the fluid is that old the seals and components bond with it.when it is totally flushed it has nothings to "grip".other people have changed just their gasket and filter and some fluid and had no problems at all.but others with the flush have problems that never existed and others have said it cause no problem.the flush sucks out the fluid in the tourqe converter.as just a changing fluid from pan doesnt.as far as the whining.i dont know.hope this helps.

bmxracr96 · 05-21-2009, 20:21

First time flush, previous to this pan was dropped twice before regular service. Flush was done at about 110k. The noise is definately in the bypass. I am looking for info on how this bypass works and how it can be tested to see if there is a blocked line that is causing the whine. Its weird that It started to do it again after the new bypass, maybe it was defective. Maybe the cooler is blocked.

Do they sell a aftermarket setup that would eliminate the bypass?

and let me describe what I am calling the whine. It sounds exactly like hydraulic pressure going through a partially closed on/off valve. It like flutters at a high frequency. Its been doing this for awhile now, roughly 20k miles. I have pulled small to lightly loaded medium trailers with no issues. No MIL light, No codes. It just cries when I take off

**360ci** · 05-22-2009, 05:15

I thought it was primarily Dodge transmissions that were prone to failing after a flush! Given that you've put 20K on the trans already I don't think the noise is a very bad thing, providing fluid levels are correct. The cooler may be blocked, as a flush can dislodge large particles that would otherwise have stayed in place. As you mentioned that the transmission would vibrate...I'd take it to a good trans shop for a proper diagnosis if no one can give you a solid response here.