5r55 questions

[6gun]

Currently: '99 XLT 4.0,4X4,5R55, Unknown mileage but well over 230K

I'm about to begin a mild makeover to include 2006 SD axles, 5.38:1 gears, Trutrac Front, Grizzly locker rear, turning 39.5X12.50R17 Kanati Mud Hogs.

This truck will be taking us on a roughly 5,000 mile adventure in Sept across the Mid-West into the Colorado mountains and home (hopefully). Full fresh fluids and filters are planned beforehand. Long winded intro out of the way now.

Question is have any of you used "Performance trans fluids IE: Royal Purple, Amsoil, B&M Trickshift, etc, and if so would you again? The old girl has treated me well and I'm not afraid to put money into her one bit. Just looking for the best fluid possible. I also plan on adding a larger trans cooler in the process so if you have any suggestions on that, or any other comments I'd be happy to hear them.

 

[RangerFabWorks]

Amsoil has a cult following. Lots of people swear by it. Never used the stuff personally.

IMO. best fluid you can get, is the original motorcraft Mercon V fluid. It’s already synthetic. And half the price of royal purple,

B&m trick shift is just super thin fluid essentially. Very hard on the trans. Would not recommend using it.

 

[bobbywalter]

Currently: '99 XLT 4.0,4X4,5R55, Unknown mileage but well over 230K

I'm about to begin a mild makeover to include 2006 SD axles, 5.38:1 gears, Trutrac Front, Grizzly locker rear, turning 39.5X12.50R17 Kanati Mud Hogs.

This truck will be taking us on a roughly 5,000 mile adventure in Sept across the Mid-West into the Colorado mountains and home (hopefully). Full fresh fluids and filters are planned beforehand. Long winded intro out of the way now.

Question is have any of you used "Performance trans fluids IE: Royal Purple, Amsoil, B&M Trickshift, etc, and if so would you again? The old girl has treated me well and I'm not afraid to put money into her one bit. Just looking for the best fluid possible. I also plan on adding a larger trans cooler in the process so if you have any suggestions on that, or any other comments I'd be happy to hear them.

a new transmission and high quality torque converter. mercon fluid....giant fat bastard cooler with thermal bypass and fan.

 

[Dirtman]

I agree with using motorcraft mercon v. Ford engineers know what they are doing. I have never been a fan of any of the "universal" fluids. Ford designed that trans and that fluid to work together and I see no benefit from straying from that.

I do however always add a bottle of lubeguard red to my older transmission and it has noticeably made a difference. Its one of the very few additives that isn't snake oil and is actually recommended by Ford under certain circumstances.

All that being said with over 230,000 miles and the mods you are planning that transmission is not long for this world.

 

[6gun]

Thanks for all the replies!

I know I'm kinda gambling on longevity but that's why I called it an adventure and not a vacation! Sounds like Motorcraft Mercon V will be my fluid of choice.

As far as additives, while I don't believe in "Chemical fixes for mechanical problems" being a former diesel mechanic I am a firm believer in Lucas oil products and have ran their auto transmission treatment in every auto vehicle I have owned the last 20yrs to great results(knocking vigorously on wood!).

 

[Craig0320]

All the replies are spot on. Cooler with fan, mecron fluid and no universal. Lubeguard red does work. I have never strayed away from factory trans fluid on ford or gm.