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?