Transmission whining after fluid change

I just changed the filter and fluid in my tranny and quickly noticed that when in neutral or park in makes a slight whining noise. I'm pretty sure it wasn't doing that before the change. I'm kind of afraid to drive the thing.

What could cause this?

I'm worried there might be something wrong with the filter I put in. But I really don't want to drop the $40 worth of fluid I put in to check... I mean, you just plug the filter in, how could I have managed to screw that up?

Could it just be air in the fluid? Perhaps draining everything which may have included the fluid in the pump allowed air into the passages then when starting it air may have been emulsified into the fluid. I have had this happen when the power steering system got too low in a couple of my cars, after topping it up it still whined for about a week or so until all of the air was expelled from the fluid.

If it also shifts very firmly them I would suspect a code p1811 to be set. Usually has to do with the EPC solenoid failing. If the filter was restricting the flow I would think you would have terrible slipping and poor shifting overall. Make sure the fluid is topped up and not overfilled. Also, you used the proper dexron fluid correct? Back in my high school shop days I filled my car with mercon because there were jugs of it available for free...but it did not shift very well at all :rofl:

I used Dexron VI. It's supposed to be backwards compatible with Dexron III transmissions, or so they say...

I drove it to work today, about 14 miles. I took it easy on her and went slow, just in case. In seems to shift fine, but I swear the sound is getting louder. When I got home tonight, I got out and listened under the car and it just sounds like crap.

I don't know what to do here...

http://bimmer.roadfly.com/bmw/forums/e38/forum.php?postid=1755714

sounds similar, apparently aftermarket filter starved the pump for fluid in a bmw

That's exactly what I'm afraid is happening. Although, I'm not sure these can collapse, but I suppose there could be something else wrong inside that is restricting flow. It was a cheap Autozone filter (although the damn thing cost almost as much a Filtran), so it wouldn't surprise me...

This clearly isn't going to fix itself, so I guess my only option is to drop the pan again and try another filter (I'm getting a genuine Filtran this time!).

Do you think it's at all possible to save the fluid without contaminating it? I was thinking of draining into a clean tub and reusing it, is that a stupid idea? It would really kill me to have to buy 8 qts of fluid again. Especially if I go through this and the whine is still there....

well you could use a $10 transfer pump and suck all the fluid into a clean container, you defiantly need to buy another quart or two.

Thought about that. It would certainly be a lot cleaner. But I'm having a hard time finding one under $50.

EDIT:
Nevermind. I found a cheap one.

Just changed the filter... again. I was able to pump out everything but the fluid in the very bottom, which happened to be 2 quarts (good guess, harmankardon!).

Long story short, the noise is still there, though not as loud as it was before. When I dropped the pan again, I found the Autozone filter had become extremely loose and was hanging so it was touching the pan, which I think amplified the noise.

Although it didn't really fix the problem, it was worth it to find out for sure that the filter isn't restricting oil flow. Plus the Filtran fits so much tighter, and I like knowing my filter isn't going to just fall out at some point...

Since the transmission seems to be working fine, I'm gonna stop worrying about it. I took it out today and floored it 'till I hit the throttle limiter, it shifted as smooth as butter all the way up there. Ah, haven't done that in a while. :biggrin:

the filter was touching the pan? wow, good thing you went ahead and replaced that. Now i know not to get the cheap filters next time. The noise you are hearing is probably a coincidence, maybe a tension pulley or air pump?. If the transmission pump failed or was failing, you would know right away with poor shifting and/or slipping.