Their carrier oil is clearly not the ingredient in Lucas Transmission Fix that fixes transmissions, it is the other up to 40% of the product not listed on the SDS, that helps the transmission. And no, the SDS is not a recipe for what's in the product. Frankly the carrier oil could cost them no more than ten cents a bottle and I would not care, I care about whether the product works in the car. Your statement "Lucas just increases the viscosity." is not supported. The carrier for their additive package, sure that is high viscosity.
It does increase viscosity, considerably, and everything you ascribe to other ingredients
may in fact just be a function of the viscosity increase as I already mentioned.
The product doesn't "fix" anything. No wizard in a bottle has the ability to actually repair a mechanical issue and I assume you are aware of that despite the language you've used. The product masks underlying mechanical issues by primarily increasing the viscosity considerably (
otherwise it wouldn't be so heavy) and potentially altering the friction modifying characteristics, depending on what else they are putting in it.
And no, while the SDS isn't a recipe, it shows that the majority of the product consists of the cheapest base oil imaginable with a VI that's so low it's laughable. We also don't know how much of the wickedly heavy viscosity is achieved from the base oil itself or the VII they are dosing the product with.
As I already noted, increased line pressure and reduction in friction modification can stop slip. Look at folks that used to use Type F to firm up shifts for example in drag cars. Lucas of course knows this, that's why the product is so heavy.
At the end of the day, what is being achieved here is that you are diluting a fully formulated ATF that's presumably blended with base oils of sufficient quality to have a VI that makes the product suitable for the anticipated range of operating temperatures and resist oxidation, with the lowest possible group base oil whose oxidation resistance characteristics are going to be horrendous (because it's group I) and a VI that's equally awful.
Like 20w-50 will mask worn bearings, yes, increasing the viscosity of ATF will stop slipping and other things. Manipulating the FM characteristics may be taking place as well, either through dilution or through something added. Regardless, you are negatively impacting numerous aspects of the fully formulated ATF with this product, that's in spite of the "benefits" you are perceiving. This is the same as with the "Oil Stabilizer" which does the exact same thing (dilutes a fully formulated lubricant with a garbage base oil and tons of VII and dramatically increases viscosity).
We've been down this road before on your defence of Lucas, and I think
@RDY4WAR contributed the last time around.
At the end of the day, what you think of the product doesn't change what it's primarily comprised of and it certainly doesn't excuse the price they charge for a product blended with a base which isn't even suitable for use in a lawnmower.
This is a bandaid marketed at people trying to limp along something that either isn't worth putting the money into to properly fix or the person who owns it can't afford to. They are charging a premium for that because they can and because of stories like yours where how the result is achieved is of no consequence because the perception of the product "fixing" a mechanical issue is enough.
Personally, I was taught to fix things properly. But, I've also been in the position of being in a pinch and having to use a workaround. Having a leaking tailstock seal on the T5 in my Mustang that I couldn't afford the downtime to fix, I used a seal conditioner (Valvoline Maxlife ATF) to mask the issue until I could. So, I understand the OP's position with the value of the vehicle and his acknowledgement that this is just a bandaid and while I wouldn't go the route he has, he's at least aware of what is going on and acknowledging that nothing has actually been repaired.
