Transmission vibration

Hello,

I am a former owner of a 1990 SC. I now have a 1994 Tbird lx 4.6. I am having a problem that I am hoping you can help me with. The car runs and drives great with one exception. When lightly accelerating I get a vibration or shudder from the transmission. I know that some of the automatic transmissions have been known to have a shudder problem. This does not appear to be the transmission itself though. It looks like where the transmission crossmember bolts to the bottom of the car that there is a rubber busing or isolater there and it is worn. It is right where the bolts pass through the crossmember. It looks like this is allowing some movement in the crossmember.

The transmission flied is clean and normal looking and the car up and down shift perfect. never slips eaither.

The local Ford deal says that i would need to replace the complete crossmember to fix it and that it is now obsolete.

Can anyone tell me if there is something I am missing or point me in the right direction.

Wes

I just thought of a good way to describe it. It feels like you are driving over those rumble strips along the edge of the road that are meant to wake you up if you wander over while driving.
It sounds just like that. And if I nail the throttle I don't feel it as much or at all most of the time.
Wes

trans shudder

Replace the fluid with Mercon Five. Most of the time this will fix the shudder.

It already has it. The vibration is not when it shifts and does not feel like it is internal. It feels like the transmission itself moving.

I agree with RAPTOR.

All of the fluid needs to be replaced/flushed out, not just what is in the pan.

Yes I know and it was. As I said the problem is not with the operation of the transmission.
The transmission shifts perfect nice and smooth. The problem is not during lock up or shifting. I can cause it to happen just by going a certain speed and not even have it shift and still do it. It feels like the transmission itself is moving.

It feels like going over rumble strips with the car. Not like a transmission shudder.
I am asking about the transmission crossmember and where it bolts to the bottom of the car. There is rubber there that the bolts pass through that has failed and is visable around the bolts.

Just a thought..

What kind of shape are your u-joints in? Do you have any idea when they were last replaced? Check and see if you have on going bad in your driveshaft. Good luck,

J

Ujoints have maybe 20k on them. No problems there. I can drive the car at high speeds and there is zero vibration. Smooth as silk.

I am just looking for information on the transmission crossmember and where it meets the bottom of the car.
Wes

I had one pin out of whack in my rear u-joint and it caused the same thing. Most of the time no vibration, even at higher speeds. It only made noise/vibration at certain speeds. Good luck,

J

1987tc said:

I am asking about the transmission crossmember and where it bolts to the bottom of the car. There is rubber there that the bolts pass through that has failed and is visable around the bolts.

Click to expand...

Try this: Bushings
They're poly... will stiffen things up, and should last quite a bit longer than the rubber factory bushings.

If you can visibly see they're shot... they need replaced. My '93 has a different style bushing, but before I replaced the crossmember bushings, I could actually twist the crossmember by hand. The bushings looked fine, but after I got them out, were soft as a nerf football. I believe the '94 up bushings will need to be pressed in/out, but I'm not certain. '93 is just a drop the bolt and replace. I'm using the poly crossmember bushings and a solid transmission mount now. No worries.

Best of Luck!
That is all...

Thank you! That is exactly what I was looking for!
Wes

1987tc said:

Thank you! That is exactly what I was looking for!
Wes

Click to expand...

You're quite welcome. On the same site, there's a solid tranny mount... good idea to do them all at the same time. I'd suggest calling to make certain you get the right crossmember mounts for your ride. The center mount is the same on all MN12s. The center mount from the factory is a sack filled with hydraulic oil encapsulated in rubber. It was made to isolate vibration. Over the years, it'll droop like a hound dog's ears if it stays sealed. When I replaced mine last year, I had to jack the tranny up another 1-1/2" to get the new mount in. Put the pinion angle back where it's supposed to be. Made a WORLD of difference in driving the car.

That is all...