Haven't heard of transmission leaks due to changing to Synthetic. Have heard of this for the engines a lot.

I would think that once we use Semi-Synthetic, it would move to Full Synthetic and not have any leak issues since the cleaning is very good on Semi-Synthetic over a conventional oil.

If I understood the Mercon vs Mercon V the Mercon V is a Semi-Synthetic. So far, after I think about 90K miles since I switched, no leaks on the Mercon V.

Also, based upon how clean the internal visible parts and pan are when I remove drop the pan, it makes me think I should be safe to switch to Full synthetic and not fear a leak.

Any thoughts on that philosophy?

X-Hemi, interesting how they say screen? The filter material appears to be a polyester type material and not a fiberglass or metal type screen as one would think is like your windows on the house. Back Flushing will just push the dirt back into the system, so I personally run hard when I hear responses like that from a dealership or any service provider!

There can't be anything better than dropping the pan, remove the dirty filter and put in a new one, then do the flush. I just don't get the mentality of not following common logic in proper maintenance.

 

I agree that going from a semi synthetic to full synthetic most likely will not cause any problems. However on high mileage vehicles going from the old style merc 3 to synthetic can cause leaks. It happened to our 94 trucks transfer case, at 350K miles we switched from the normal atf to full synthetic to help gas mileage. It all leaked out within 20K miles and locked up the transfer case.

 

Strictly to pic nits, there never was a Mercon III. It was Dextron III/Mercon.

Stewart

 

I know but dexron is a chevy thing so I don't like mentioning that part.

 

You have to realize I was talking to a service "writer" and not the actual mechanic.

We always tell people to RTFM and talk to your manufacturer on these forums so I feel comfortable with allowing Ford to utilize their manufacturer developed procedures on this service.

While I feel qualified to do many maintenance items (and I'll once again be changing brakes on one of my cars and do all kinds of things on them)...as I crunch the numbers on this...it just doesn't add up for me with the fluid costs and my time versus dealer costs.

As far as the size of the 7.3 vs V10 vs 6.oH coolers...yeah those are striking differences!...in real world towing experience for me...I have found that the V10 cooler is sufficient for my needs though...I guess if I ever had a need or reason to change my cooler...I would consider the 6.oH cooler though.

Joe.

 

I've found it's a common mistake by some, calling it Merc III instead of Merc, when referencing Dex III/Merc.

Like I said, just picking nits on my part...i'll just move along now...

Stewart

 

It takes a 1/2" if I remember right and it is located on the passender side of the tranny.

 

my 03 eb 4x4 has 285k and no idea if its orig tranny.

i bought 20 plus quarts of mobil 1 synthetic trans planning to chg fluid. called best trans shop in milwaukee to confirm my thought process and guy said dont touch it if it shifts good and otherwise works properly. "dont rock the boat". once it starts acting up, change over then he said. also said dont touch filter until issues are noted.

i have heard of this theory before but always thought improving fluid would be a good thing no matter what. any truth to what this trans specialist says?

 

Not for the trans in your rig.

Back in the day, yeah, but not anymore.

Only good can come from replacing the trans fluid in your 4R100.

Stewart

 

Yup, change that fluid!

 

All of the older mechanics have that "dont touch it" advice. My brother in law who owns a successful shop in a big city told me to leave the fluid alone in vehicles you dont know about. I have no idea if/when my 90K mile fluid was changed last.... They say the clutch material/sludge in your old fluid could be whats keeping things working and changing to new fluid would drop pressures and change frictions to the point that things might slip. I want to trust him, but think I will feel better having it flushed. I swap engines under my carport, but dont like disposing of that much fluid and hate the smell of trans fluid, so i will pay someone for that messy hassle.

 

Yep.

You do realize how counterintuitive, idiotic, and illogical that line of thinking is, right?

Stewart

 

I always heard the same things and asked the same question here and had the same worries. I flushed my fluid and couldn't be happier! Flush that fluid!

 

Oh I never said I believed it. I have on the other hand I once had a Tbird trans flushed only to have it start flaring shifts and slipping. Flushed by one of those machines that hooks to your cooler lines. I had to have it rebuilt and the builder said the flush killed it. Who really knows for sure. I think I will let Ford do the Excursion. First thing I have taken to a dealer to pay for myself out of warranty in a long time.... On the plus side, we go back a long time and they all know me by name there, so im sure they will take care of me.

 

I just did this flush on my new to me Excursion. It has 196k on it, the fluid was a bit dark but still had some bright red in it. It took 22qts to flush and now with a new filter I feel confident it was the right thing to do. The magnet had some minor gray gook on it, normal. It does shift a bit better also. The procedure is not as difficult as it sounds, and I would recommend this to anyone thinking of it. It costs about half of what the dealer wanted for just a flush and I know this was done right.