Anyone have any luck with LUBE GARD Instant Shudder FIXX in there 10R80?
I have a 2018 F-150 4x4 5.0 with 80k on it and have shudder at 35-40 and 55-60,
I put two 2 ounce tubes in. Only ran it 10 miles so far,
How long might it take and any suggestions on
what speeds are best to run at and for how long continuously?
Should a manually shift through the gears up and down while driving ?
Hoping it works !!

 

you may want to do a filter and fluid change Motorcraft friction modifier is basically the same thing just more of it put in a bottle

 

already did a dealer service, they did a total back, they claimed it got all the fluid including the converter and pushed everything backwards out of the screen ( filter).

 

Ford Friction modifier is for Traction Lock rears with Clutch Discs Paks each side so they (don't lockup "so hard") on a turn.
I don't think that is what should be done by using it in a 10R80 to >>prevent slip with any parts that need to friction Lock up during gear changes.
10R80 has Friction Disc Clutch Packs as well as the TC Lockup does.
Good luck.