93 Eurovan transmission noise

[93 Euro]

often i hear a big thump when i am driving around town, usually when i am decellerating , and more so down a hill. When i bought it from a friend he said it has always done that. I has not increased in frequency for me for almost 5000 miles. i have 133k on it. recently changed the traney fluid for second time since 5k miles ago b/c it was "black" but not burnt per the mechanic. had a few filings in it but told normal for age .
It shift fine. goes up the hill and shifts properly. sings along at 70mph on flat highway without probelm. the thump has not seemed to change in frequency or any other changes.
Also was always told that 93 automatics shift rough. do other folks 93s thump? Sounds like someone kicked the floor board. but shifts great otherwise.

[gti_matt]

Transmission mount. If something feels like someone is kicking the floorboard, that's the first thing I'd check. It's either loose or worn out.

Does it do it in a straight line and just when shifting? If so, I'd really suspect the transmission mount between the trans and the rear part of the subframe.

Or does it do it when turning? If turning, could be tie rod ends or ball joints. Mine (manual trans though) transmitted a loud "thunk!" under the floorboard going around turns and hitting a bump while turning and ball joints and tie rod ends fixed it.

[januwan]

I have the same problem but only when I slow down (down shifting). I replaced the transmission mount 5 years ago. May be it is time to do it again. I have 207K miles on my 93 Euro

[93 Euro]

Thanks. Prior to posting this they told me my transmission mounts were fine. but I am wondering if they were mistaken. I may bring it elsewhere.
sounds like you have 200k miles on your original transmission. that is encouraging. I will hope for the same...
If u have a 93 euro weekender do you know if the auxillary battery under the seat works the interior lights without having to do anything. there is a orange toggle switch on the outside of the drivers seat, but not sure what it is for.
Thanks in advance

[93 Euro]

It happens in a straight line. often when i let off the gas. i have an automatic, but seems to occur when the engine is downshifting.
I had the mounts checked prior to posting this, but i wonder if they new what they were doing. i may bring it elsewhere.

thanks. p.s. do you know how to engage the aux battery under the seat? i have a weekender and not sure if the interior lights and radio will draw automatically from aux battery when ignition is off or i need to do something. thanks !!