I have a 2000 5.4, 4R100, 4X4 and recently had the trans flushed by the dealer and the fluid changed. I noticed that they used Mercon V fluid (XT*5*QM) when they changed the fluid. I called the dealer back, talked to the Service Manager and he said that fluid can be used with this trans with no problems.

Truck is running fine after about 500 miles. When Ford says they are not compatable with one another, are they saying just do not mix them together (Mercon and Mercon V), or do they mean that Mercon V should never be used in the 4R100?

Thanks in advance.

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2000 F150 XLT SuperCab, Short Bed, 4X4, ORP, 5.4L, Auto Trans, 3.55LS, Captains Chairs with power drivers seat, rear slider, class III towing package, remote entry with alarm and just about everything you can get on this truck. Added a Ford bug deflecter, floor mats, a Dynamax Race magnum muffler and 3" mandrel bent pipes, Superchip, K&N FIPK Gen II, Bilstein shocks, Redline Synthetic oil, Kenwood stereo system, an MTX Thunder 204 4 channel amp, ProComp AT 33/12.50/17 tires and 17X8 American Racing Python wheels.

 

I was under the impression that it couldn't be used in the 4R100, mixing a samll amount isn't a problem, because it happens in the factory sometiems and there is a spec for how much of one type can get into another, (we also build the 5R55N, which uses Mercon V and sometimes the fluid lines get some of one type in where the other type is going, don't know how it happens but I know that there is a provision for it) I myself would go back to the dealer, point to the page in the manual that says "MERCON" only and make them change it again. It's about half likely that the tech looked up F-150 and saw MERCON V (which is what a 4R70W would get) and put the wrong type in, without being aware that the 4R100 uses a different fluid. Stanger things have happened.

G

 

The owner's manual in my 2001 (and the 2000 I had before it) says not to use Mercon V in a 4R100. Look in your manual - it is in the last couple pages.

Mark

 

Well, I got the Mercon V flushed out and replaced with Mobil 1 synthetic Mercon. Could not wait until Tuesday since I have to be back in Death Valley by then. I know someone that manages a quick change place, so he did it for me. Really tough to tell the difference in performance though. Shifts may be slightly "crisper", but no major difference.

I will talk to my dealer about this as soon as I get back in town.

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2000 F150 XLT SuperCab, Short Bed, 4X4, ORP, 5.4L, Auto Trans, 3.55LS, Captains Chairs with power drivers seat, rear slider, class III towing package, remote entry with alarm and just about everything you can get on this truck. Added a Ford bug deflecter, floor mats, a Dynamax Race magnum muffler and 3" mandrel bent pipes, Superchip, K&N FIPK Gen II, Bilstein shocks, Redline Synthetic oil, Kenwood stereo system, an MTX Thunder 204 4 channel amp, ProComp AT 33/12.50/17 tires and 17X8 American Racing Python wheels.

 

Thanks Factory Tech and everyone - I already knew that the 4R100 uses Mercon. Unfortunately I didn't find out about them putting in Mercon V until I got the truck back, and then the Service Manager insisted that it was all right to put Mercon V in the trans.

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2000 F150 XLT SuperCab, Short Bed, 4X4, ORP, 5.4L, Auto Trans, 3.55LS, Captains Chairs with power drivers seat, rear slider, class III towing package, remote entry with alarm and just about everything you can get on this truck. Added a Ford bug deflecter, floor mats, a Dynamax Race magnum muffler and 3" mandrel bent pipes, Superchip, K&N FIPK Gen II, Bilstein shocks, Redline Synthetic oil, Kenwood stereo system, an MTX Thunder 204 4 channel amp, ProComp AT 33/12.50/17 tires and 17X8 American Racing Python wheels.

 

Kind of funny how Amsoil makes 1 ATF that meets both Mercon and Mercon V specs.

I guess if you are in doubt use one product that covers both!!!!

http://www.amsoil.com/products/atf.html

Meets or exceeds the following performance specifications:

GM Dexron II, Dexron III
Ford Mercon, Mercon V
Chrysler ATF+, ATF+2, ATF+3, ATF+4
Allison C-3 & C-4
Caterpillar Powershift Transmission TO-2 & TO-3
Voith Commercial Transmissions
GM Strasbourg (European Imports) and Opel


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Hey guys-
I need to change my tranny fluid and aint sure what to use? The dipstick says Mercon V.
I guess thats what will use. How can I tell what model tranny I have?
My truck is a 99F150 sc 4x4 5.4l auto w/3.73ls . Is there a tag or # that will tell me my tranny? Thanks.