Please Help: Transmission Question on 3.8L V6

[erasure213]

I own a:

1997 Ford Mustang
3.8L V6
Automatic Transmission with about 71k miles.

Lately, I've been experiencing a minor shake when I'm on the freeway and accelerating from 50 to 60 mph. I don't know how to exactly describe it, but it feels like a shudder or choke when it accelerates or shifts. I've also experienced a drastic decrease in gas mileage. I would like to take my car into an automatic transmission specialist tomorrow and would like to know what I need to do to fix the problem.

A few weeks ago I brought in my car to an AAMCO and they were trying to tell me that I need to rebuild my transmission. They tried to explain to me that my transmission fluid has never been changed, because they showed me a dipstick plug, or filler plug inside the transmission fluid/pan. I don't really believe this because I talked to the ford service person and they said that the transmission fluid could have been changed, and not been flushed out, therefore leaving the dipstick plug still inside. The AAMCO guys weren't able to show me any pieces of metal in my transmission fluid, it was just dark. Therefore, I'm suspicious as to what they are telling me.

So I've been posting on other forums and everyone recommends that I just take my car in for a power transmission flush and replace the fluid and filter. They say that should take care of the problem.

Does this sound like a problem that anyone else has encountered? Do you think there might be something more serious? Or is it just as simple as changing the tranny fluid and filter, and the problem should be cleared?

Thanks in advance.

[HiFlow5 0]

I say take it and get the filter and fluid changed, then see what happens. Also Aamco doesn't know their heads from their asses! I know this from experience, had my old AOD rebuilt by them, then 8 months later it went out again, then 1 month after the warranty ran out, the front pump went out. It also had a hang up condition after both rebuilds, supposedly they pinched a seal on reassembly, both times. Take it to a local tranny specific shop or a dealer.

[Mendari]

I agree with HighFlow5 0, do not take it to AAMCO. I've never heard anything good about their company. I recommend getting the transmission fluid flushed and the filter changed. It should cost less then $120 and it's the best starting point for further diagnostics.
Is it a convertable? If it is, Ford is addressing a problem with the subframe connectors in the situation you have described. Search for "Article No. 00-9-7"

[erasure213]

I called a few places about getting a transmission fluid change and there's a different type of transmission changes I can get. Should I have a power flush where they drop the pan? A place I called said its better just to change part of the fluid because if I replaced the whole thing, it can damage the parts? Who should I believe?

If I power flush the transmission fluid and replace it with entirely new ATF, should that be ok?

Thanks.