Lazy Daze Owners' Group

Ford 4R100 transmission questions

October 08, 2013, 07:52:00 pm

Yahoo Message Number: 143058

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Apology:  this is the first time we have logged onto Yahoo since all  the big "improvements," and I cannot locate the reference libraries or Q&A  pages at all, and my husband has a question about automatic transmission fluid,  so if this has been discussed elsewhere previously, we apologize.

Pat, Piscataqua River 30' LD IB

Here's Bob:
 P. River is based on the 2000 Ford E-450 chassis with the V-10 engine and  the 4R100 transmission.  It now has 42,000 miles on it, and according to  the book, is overdue for a trans fluid change.  This unit is supposed to be  filled with Mercon, but Mercon is no longer available.  Mercon V is the  official substitute, but some sources say DO NOT mix the two.  This would  mean that the trans and the torque converter should be thoroughly drained before  filling with Mercon V, and the refill should be 15 to 16 quarts.  Has  anyone had experience with this situation?  If so, did you A) do it  yourself?  B) have a Ford dealer service dept. do it? C) go to a  transmission specialist like AAMCO? or D) have an independent service shop do  it?  I recall seeing one report of a Lazy Dazer who had synthetic trans  fluid installed and wound up with a ruined tranny.

Re: Ford 4R100 transmission questions

Reply #2 – October 09, 2013, 12:35:25 am

Yahoo Message Number: 143065

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Pat

Confusing, isn't it? Our 2003 LD's owner manual states, in bold lettering, not to use Mercon V.
Then back somewhere in 2006, Ford decides to stop production of Mercon and that Mercon V is just fine for the 4R100. What changed?
 Here is a chart showing Ford's present ATF recommendations, for its various transmissions. machenry.com/documents/atffluidchart.pdf It shows your 4R100 using Mercon V as the replacement for Mercon.  Interestingly, Mercon is also known as Dextron III and is still available at Napa.

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/A-Trans-Fluid-NAPA-Dexron-III-Mercon-1-Qt-/_/R-NCA75200_0274141270 So you do have a choice, stay with the original recommendation using Dextron III or use Ford's Mercon V replacement.
 I suspect most 4R100 model owner's have switched to Mercon V. I still wonder...

Switching to Mercon V does require a total replacement of the fluid. The flushing, done through the transmission cooler's supply line, and refilling will take about 22 quarts before the fluid run cleans.
Any competent auto mechanic should be able to do it. Transmission shops have a power flushing machine.

There are a lot of LD's running synthetic ATF.  Mobil 1 synthetic ATF is listed for transmissions using both Mercon and Mercon V. Like switching from Mercon to Mercon V, the transmission needs a through flushing when switching to synthetics.
 After seeing how clean the drained ATF is, from our LD, I'm sticking with a conventional ATF and changing at the the recommended 30,000 intervals. The E450's cooling system does a good job of keeping the transmission oil cool and from deteriorating. Synthetics may be overkill in this situation.

Larry

Re: Ford 4R100 transmission questions

Reply #4 – October 09, 2013, 02:59:50 pm

Yahoo Message Number: 143071

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Bob,
 I change my 4R100 oil at about 38,000 miles in my 2000 SOB, dropped the pan, new filter in the pan, drained the transmission cooler and the torque converter (the 2000 models have a drain plug on the converter - take off the cover plate on the bottom and rotate the converter until you see the plug).  I refilled with Mobil 1 ATF and now have over 60,000 miles on it with no ill effects.  I did find, however, that the transmission fluid temperature on my ScanGauge II reads lower now and has never exceeded 225 degrees climbing grades in Arizona.  I even use Mobil 1 in my 20 year old Toyota pickup!

Glen

Re: Ford 4R100 transmission questions

Reply #6 – October 09, 2013, 06:07:02 pm

Yahoo Message Number: 143075

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Bill, your 2003 (and mine) has the 4R100 four-speed transmission.  This link is a very handy "model changes by year" reference:
 http://www.andybaird.com/travels/LD-guide-web/changes.htm 
Joan