I used it in three diesel Landcruisers, and never noticed much difference in engine performance or longevity.
Where it did shine was in the gearbox of the first HZJ75 that I purchased from a mine in Queensland...the gearbox was shot, and I was broke so I dumped Slick50 into it and drove it for a further 2 1/2 years by double clutching in each gear and swearing every time the damn thing dropped out of fifth.
When the local Toyota dealer finally got the job of overhauling it they were somewhat surprised to find the bearings fell apart when the unit was dismantled, the mechanic and the dealership owner were horrified and somewhat shocked the thing was still working.
It felt fine apart from the aforementioned issues, and had lugged heavy loads across soft paddocks and mud with no problems that stiff bouts of profanity and dark thoughts could not ease.
