If you have over a 100k on your trans and you've never changed your fluid, and the trans if fine, don't do anything. But if you've religiously changed your fluids over the years, Do whatever you want. GM says to flush the trans every 50k
Actually, if you look it up, you will find studies showing that engine and transmission oil additives do more harm than good. Oil treatments leave deposits that clog your oil passages. Tranny treatments leave a film on the clutches that make them slip and wear faster (hence the smooth shifts) and break down the seals. Use dexron tranny fluid and any oil with the star seal on it and nothing else.
the lucas oil stabilizer is just a thickner. It has no additives and especially no anti-foaming additives. It just thickens oil. So in reality it dilutes the add pack in your current oil. Their gas treatment is okay, but I wouldn't touch any of their additvers.
There are very few oil and trans additives that are worth a darn. One of them is auto-rx.
A while ago i asked a friend of mine if it would be ok to run a full synthetic tranny fluid in my 1995 9C1 Caprice.He said NO,it has been known to cause the cluches and what not to slip,ect...Basicly wearing out your tranny prematurly.
So needless to say i stuck with a good quality dino oil and AC-Delco filter and torque converter seal.The guy i sold the car to said that his tranny is still going strong
Synthetics seem to be ok in anything but GM trannys.I had a 1998 Ford Crown Vic that had pure sysnthetic tranny fluid put in it.That tranny as far as i know is still going great.It even seemed to make the shifts "firmer" so that was a nice plus.