Well in some of my other threads you may have read I have been having serious trouble with my ZF542. Every down shift to 2nd is a major clash and only comming to a complete stop can I shift. 60% of my upshifts to 3rd grind and almost every down shift to 3rd is a clash causing me to stop also. I had dumped the fluid which was ATF and a little low. Ist try was Penzoil and ATF Mercon the crashing was worse. I started to look for a new deal on a good ZF5. I read several accounts of guys useing RP with great results after a week. As with redline and some other brands but I have always been skeptcal of these types of claims. I also noted Ford has high regard for RP. So I spent the bucks to try the royal Purple Synchro fluid. All the way to the fill hole and after a couple of days the clashing was driving me crazy. Ihad put a couple of hundred miles on it and on day 3 I got in and put it in reverse and a huge clunk. Kinda scared me but I took off a bit later I was leaving a parking lot and clunk again then it wouldn't shift. I finaly got it into low range and it seemed to work back in to place so I took it up to the top of the Horse Heaven hills here and drove for miles in 2nd and 3rd. It did seem to start to quite down. Today I took it for a 150 mile run. The grinding noise in nuetral has been cut in half. It never clashed 1 time today and down shifts into 3rd were clean. I was still very careful going into 2nd (still chicken) but never even a scrape. The gear whine in 3rd and 4th are almost gone. All I can say is that I am amazed. This RP product seems to have loosened up the synchros and is a very excellent lubricant. I am not prone to this kind of review but it is incredible.

Just thought I would pass it along. I always avoided Royal Purple because of the cost but not anymore.

 

Couldnt give you any RP insight but,

Those pictures are amazing. I like the scenery!

 

Make sure to use the Royal Purple violet scented air in your tires...or it won't balance out properly and you'll be stranded in the field.

LOL

I'm just kidding, I'm glad that you found a product that helped your truck shift better. I've been using RP for years in my performance vehicles. Great company!

 

No way I would believe it if I had not used it myself.

 

Here is a couple more from the hills above where I live. I took them from the truck so I guess it's ok. lol