I have personally ran the mobile 424, lost a converter to the fluid. I had the converter cut open by the manufacture and was told fluid was incompatable with lock up clutches. In the mean time the trans builder took a look in the trans to find nothing wrong, reinstalled trans with a rebuilt converter and ran dextron for the next 5 years with no problems.
The trans builder contacted me when he lost another lock-up converter due to the use of mobile 424 a few months later, now we both do not recommend the fluid.
This is personal experience, not just saying it does not work, finding out it did not work in my car and having to pay the bills and redo the work.
Maybe there is something to this, but I will not recommend if there is a possibiltiy of failure involved.
Question for all? I used it in a daily driver which got a good workout every day. So maybe 10 years in a car with 100 miles a year it would be fine. So how many miles are being put on these trans with the mobile 424 and how well does your converter still lock up? I would like to know the facts, of how many miles and what type of converter please, not speculation.
Dextron fluid always worked.
Thanks
Bill