'93 Grand Voyager ATF and rough shifts

The easy part. Should I fill my tranny with ATF+4 or search for +3? It seems
most of the local places only have +4 now. It's a '93 Grand Voyager 3.0L, 3
speed auto (A670 I would imagine), 203k kms.

The harder part. This tranny has always had hard upshifts, especially when
cold. By hard I mean it bangs into gear with a good jolt even when very
gentle on the gas. The first 1-2 and 2-3 upshift is usually very hard, and
it usually shifts hard when between gears in stop and go traffic. It's
usually a little less violent (sometimes downright smooth) if I stay on the
gas a little, which is tough in traffic. Not a new problem, it has been
doing this for years now. The previous owner (my late father) never
considered it to be a problem but obviously something isn't right. It never
EVER slips, it just bangs into gear. What are the odds that a simple band
adjustment would help? Anything else I could check? Symptoms seem odd too me
for a bad mount, what do you guys think?

Now that I think about it, would running Dexron cause the rough shifts? I
did a pan-change a while back with ATF+3 and it got a little better for a
while, but that was by no means a complete change. If it had been filled
with with the wrong fluid at some point before that... Whatcha think?

 

ATF+3 was recommended even for the 3 speeds at the time this vehicle
was assembled. ATF+3 has been made by Quaker State, and Valvoline if I
remember correctly for some time, so it should not be hard to find.

I would suggest taking your van to a competent transmission shop to
determine that hard shift problem.

-KM

 

ATF+3 was recommended even for the 3 speeds at the time this vehicle

True, but ATF+4 was obviously not available at the time the vehicle was
asssembled. I know it is recommended for most older model Chrysler trannies
with some exceptions, including those in some (all?) of the minivans. Hence
the question, should the A670 be filled with ATF+3 as spec'ed back in 1992-3
or the modern ATF+4?

Last resort. If the symptoms could be caused by something simple I'd rather
investigate that first rather than risk getting hosed at a shop right off
the bat.