ronaldmignone

I want to submit this with as many tips that I can remember. Quite a few of the comments that I have read don’t describe the full job of drilling and tapping a drain hole in the 2012 Ford Edge AWD PTU (Transfer Case).

In AllData and Chilton the fluid capacity of the PTU is listed as 18 oz. There have been comments in various threads that the best level of the 75/140 lube oil in the PTU is anywhere from 3/8 inch to 1 ½ inches below the fill hole. I left the level at the bottom of the fill hole because I think the more lube oil the better.

My Edge has 61,000 miles. The only way you can access the bottom of the PTU is to raise the front end enough to crawl under the Edge. I do not have a lift. I have a two-car garage with a seven-foot ceiling. I raised the Edge high enough that the front tires were 4 inches off the floor. Use caution in placing the floor jack point directly to the side frame just behind the front suspension on each side. Place the jack stands just behind the floor jack (floor to frame). I did not raise the rear purposefully. I do not believe that the vehicle needs to be level when filling the PTU. The full 18 oz. of lube oil was pumped into the PTU at the end of my job. Remove the right-front tire.

Remove the small protective guard from the drivetrain mount (10 mm socket) Reinstall when finished.

Set the center point of the drain plug. From the edge of the PTU half measure 18.5 mm. Be careful, there is an 10 mm thick adapter ring between the case halves. Don’t measure from the wrong edge. Measure 23 mm from the center point of the neighboring bolt. The cross of these measurements is the center point of the hole that will be drilled. The engineer that supplied photos of this measurement is in one of the threads in this forum.

I decided on a ¼ NPT threaded hole. If I messed up I would drill and tap a 3/8 NPT hole. I found an S.S. ¼ NPT plug with a square 3/8 head. I have square head sockets. I used four drills from 1/8 up to 5/16 to drill the hole. The 7/16 drill did the final job. The lube was leaking out after the first drill so I used a 4-cup clear plastic measuring cup. I drained out 16 oz. of dark lube oil. The oil did not have a burnt odor. I think the other 2 oz was undrainable (low points). Once done drilling I removed the fill plug by reaching behind the frame cross member with a 3/8 ratchet. It was easy to reach and easy to remove. I called it a day and allowed draining overnight.

The next morning there was a lot of wiping, with paper-shop-towels, to clean up the dripping oil. The exhaust pipe had a lot of oil on it.

I cut the threads with a ¼ NPT tap. The head of the tap is 7/16 inch square. I used a 7/16 square socket (3/8 drive), extender, and the adapter to a ½ inch drive T handle. The handle is 8 inches long. Before I started cutting thread I measured, with calipers, the large and taper diameters of the cutting threads of the tap. I measured the large and tapered diameters of the plug threads. I estimated the wall thickness where I had drilled the hole to be near 7/16 inch. I marked, with a felt-tip pen the taper diameter of the plug on the tap. And measured up the tap nearly 7/16 inch and wrapped duck-tape there. I cut threads until the tap reached the tape. There was about a thread or two exposed on the plug after I torqued it.

I filled the PTU with ATF (Ford -spec) drove around the neighborhood block and then drained. (I had to install the tire, take the Edge off the jacks and then Put the Edge back on jack-stands and remove the tire again). The ATF came out just slightly darkened. I then final-filled the PTU with 75/140 Ford-spec lube oil and will drive nearly 800 miles and then drain the PTU and refill with Motorcraft 75/140 Synthetic lube. A year from now I will service again. The shaft seals on the PTU were not leaking. My next job later on this summer is to replace the lube in the RDU (rear Diff.) and also do the transaxle flush routine with 12 quarts of Mercon LV ATF.

 

 

I was just after an experience like yours. I want to drill a hole to install a drain plug in the PTU of my Edge 2011. Would you be able to send me a picture of your PTU so I can see the exact location for the PTU drilling of my car? I do not want to make mistakes.