I was going to put AMSOIL Multi-Vehicle automatic transmission fluid in my 2000 E-459 Super Duty with a 4R100 tranny, but the owner's manual says don't mix the types if yours uses Mercon. Anyone got some insights on this?

 

Should be okay if you flush out the current fluid (Mercon V?). A pan drain then fill with Amsoil might not be a good idea.

Sixto
07 E350 5.4 198K miles

 

The trans came from the factory with MERCON ATF. MERCON was discontinued in 2006, and MERCON V was reformulated to be compatible with the 4R100 and other transmissions that used to use MERCON.

I recommend a synthetic MERCON V ATF. AMSOIL is not MERCON V rated, though AMSOIL says it will work.

 

Not a fan of Amsoil anything
Some Fords leak oil
Most Fords running Amsoil engine oil, leak oil or will start soon IMO
I have been watching that stuff make Fords leak oil since 1979

 

I used to know a guy that had all seven possible ASE master tech certifications. He told me he loved AMSOIL. He loved it because it provided so much work for him with needless failures. He said he would NEVER recommend it but was happy others used it to keep him working.

 

Factors that come to mind with ATF alternatives are cost, lower fluid temp, longer drain interval and transmission plain lasts longer. I don’t know that any alternative has been scientifically and conclusively proven to outperform Mercon in use. Alternatives might do better in generic lab boiling and shear tests.

Valvoline MaxLife ATF is half the cost of Motorcraft Mercon V and Amsoil but you’re saving $80 over 50k miles. You need fleet volume to realize a benefit.

Then the question of whether Motorcraft Mercon V is better than Valvoline Mercon V or Walmart’s Super Tech Mercon V.

Sixto
07 E350 5.4 198K miles

 

I also have all 7 ASE's + L1 and a Ford Chassis Masters, I hate replacing rear main seals, and agree wholeheartedly
I do have friends around here that have run the stuff for years and love it

 

MaxLife is not MERCON V.

 

Definitely! It’s an example of ATF that claims compatibility with Mercon V that’s substantially cheaper than Motorcraft. Amsoil isn’t cheaper so cost isn’t a deciding factor.

Sixto
07 E320 wagon 198K miles

 

OK, there is a reason why I asked. I'm an Amsoil dealer, so I naturally head to their products. Amsoil used to have different ATF formulations for different makes, but they now only have the "fuel-efficient" and the "multi-vehicle". I find this rather suspicious, regardless of what Amsoil HQ tells me. So, since I'm in the company of experts, is there an ATF that is recommended for a Ford E-450 with a 4R100 gearbox?

 

Mark said it in post #3 - Mercon V

Mark was a Ford transmission engineer.

Sixto
07 E350 5.4 198K mlles

 

Got a brand in mind?

 

Ah, brand. I use Motorcraft. I see Valvoline and Walmart Super Tech labeled Mercon V. I haven’t read anything about those brands. Try the transmission forum.

https://www.ford-trucks.com/forums/forum69/

Sixto
07 E350 5.4 198K miles

 

If it says MERCON V on the label, but does NOT say recommended for use where MERCON V is specified, it will be fine.

I believe the best one on the market is Mobil 1 Synthetic ATF. It meets or exceeds the MERCON V spec. I've also had good results with Walmart's SuperTech MERCON V.

When I was at Ford we supplied transmissions to an off road race team. Over the years they used the E4OD, then 4R100, then 5R110W, and then I left Ford. And this truck made about 650 HP.

These were highly modified race trucks that ran the Baja 1000, among other races. The transmission coolers were mounted in the bed of the truck with large fans supplying air. At one Baja 1000 (with a 4R100) the fans failed. We were in the lead when this happened, so they didn't want to take a lot of time in the pits to try and solve it. They worked on it, but couldn't fix it. The decision was made to run it as far as it would go to try to get the best finish possible, given the circumstances.

The trans temp gauge only read up to 320°F. It was pegged for almost the entire 1000 mile race. Oh, and we won the race, too!

After each race the transmission was returned to us for teardown and analysis. This trans didn't have any internal failures or unusual wear. The only unusual thing we found was that the solder had melted out of the solenoid body and was laying in the bottom of the pan! Solder melts at 450°F. So we know that the trans got at least that hot. And it still worked, and the trans had the usual amount of wear.

The trans fluid? Mobil 1 Synthetic ATF.

 

Good to know and congratulations!

Mobil 1 website says ATF is recommended for applications requiring Mercon; meets or exceeds requirements of Mercon V. Second part meets your criteria.

Amsoil website about signature series ATF says use in applications which require Mercon or Mercon V specifications. Umm…?

Thats difficult for a lay person to distinguish.

Sixto
07 E350 5.4 198K miles