I have a 2000 E-250 cargo van has the 5.4L engine, the 4R70W transmission, and approximately 125,000 miles. I had it in storage over the winter months and found a huge puddle of ATF underneath when I went to take it out of storage. Refilling the transmission with ATF resulted in all of it leaking out within a day. Careful inspection revealed the transmission extension housing has developed a crack near the passenger side mount, which research leads me to believe is caused from electrolysis that takes place due to the aluminum extension housing being attached to a steel mount.


I provided my VIN 1FTNE24L8YHB19094 along with a detailed description of my van to two authorized Ford dealerships who both told me that the VIN won't be much help in determining the correct part as there were 2 different extension housings manufactured for the 4R70W transmission. I was also told that if my extension housing is 11" long, I will need part# F5UZ7A039A and if my extension housing is 10" long, I will need part number F3LY7A039A. However, I continue to come up with a length of 10.5" despite carefully measuring the extension housing several times. My understanding is that the extension housing's part number located on the flange area where it connects to the main transmission case, which means that it must be removed to view the part number.


My questions are:


1. Is there any other way to determine if I have a 10" or 11" extension housing besides measuring the length or removing it to view the part number?

2. Any recommendations on the brand/part# or style of extension housing gaskets/seals that provide the best and longest-lasting seal?

3. Any recommendations on brand/part # of the transmission mount I should use to replace the original with?

4. Are there any preventative services that would be wise to perform and/or parts that would be wise to replace while I am replacing the extension housing?

5. Other than marking where the driveshaft bolts up with a paint pen to ensure I reattach it to the same position to prevent potential driveshaft vibrations, are there any other precautions that are wise to take when replacing the extension housing?

6. Is there anything I can do to help prevent the transmission extension housing from cracking again in the future? Perhaps painting or coating the aluminum extension housing mounting points with something so that they won't react with the steel mounts would be wise?

7. Is buying an extension housing with a lube mod kit installed or installing a lube mod kit on the extension housing I buy a worthwhile improvement?


http://www.ebay.com/itm/321341699318?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT


8. Is buying a used extension housing a bad idea and if not, is installing new tailshaft bushing a wise move?

9. Any suggestions on which brand/type of Mercon ATF I should buy?


I'll deeply appreciate any wisdom you are willing to share with me as I've spent hours researching this frustrating problem as it's important to me that I do the best job of replacing the transmission extension housing as possible so that the repair will be lasting and so I won't make mistakes that cause more problems.

 

The rubber on the trans mount should have isolated the tailshaft and prevented electrolisis. The tail shafts go on with silicone. I would measure the tail from the trans body to the mark on the driveshaft, where the rear seal hits the driveshaft. I would go to some trans shops and see if they have any laying around they are willing to get rid of. Other than that it's an easy fix, run a ground wire from the bolt on the tailshaft to the trans body and the other end to the frame or the bottom nut of the rear mount. Just in case. Good luck

 

Please forgive the dumb question from a non-expert:
Are you sure it's a 4R70W? My 97 E250 has a 5.4 backed up with a 4R100.

 

I don't believe that transmission made its appearance in vans until much later than 2000. 4R70W is pretty much guaranteed in the OP's chassis of that year.

 

Oh thanks - maybe mines an E40D? Now I want to crawl under it and figure it out...

Sorry for the hijack.

I do know 4R70W in Panthers had 2 tail shaft housing lengths but used the same tailshaft. Basically, cop cars got a longer housing and shorter drive shaft to address "critical speed" concerns. I had to replace a drive shaft on my civilian Crown Vic and got the aluminum drive shaft and housing used from a junkyard cop car.

 

What is the trans code on the drivers door pillar?