Changing the rear dif fluid on a 1998 Clubwagon 6.8L V10 this week. Can't find what type of gear oil is supposed to be used and whether or not I need additive. Research on the dif cover tag reading V606049-3, it's a Dana 3.73 unit. I have no idea as to whether or not it's limited slip.

Anyone have a part number for the check/fill hole plug?

 

Cut and moved to the proper forum.

Stewart

 

Pics

 

I'm sure I'm showing my inexperience here, but I'm still not understanding exactly. According to the footnotes in this manual, all Ford conventional, Ford Traction-Lok, Dana conventional, and Dana limited-slip require the added friction modifier.

So, all differentials require the additive? I had read somewhere that only limited-slip diffs need the additive. Hope I'm not being difficult. Just want to make sure I put the right goop in there.

Since I think mine is a conventional Dana 60 with 3.73 gear ratio, my guess based on this manual is that I need 3.0 liters of Motorcraft SAE 80W90, topped off with 6 ounces friction modifier.

 

Make sure you know what kind of Dana you have whether it be a 60, 70, 80. It says that only Traction Lok axles require the friction modifier.

The larger the differential the bigger the series number.

​​​​​​​I'm confident in saying you should use 75W-140 with friction modifier.

 

Oh no! Now I'm even more confused. How did you come to that conclusion?

My door jamb sticker axle code is 34, and the only tag I can find on the rear differential itself is on the dif cover. It has the code V 606049-3 stamped on it. Searching that tag digit gives me hits for "1998 E-350 Van SRW - Full Float - ABS Standard" Here's a picture. The tag is between the two rightmost cover bolts.


Is this not a Dana 60?


It does look like a PO has been into the dif case before, as there seems to be dried RTV where the cover meets the case. It could be that the cover was replaced at some point with one sporting a mismatched tag.

When I punch my VIN into the decoder tool on this website, it says that the rear axle should be "Ford Semi-Floating" which is contradictory to the info I find when searching 606049-3, the number on my dif cover tag.

 

I'm​ sorry I was very tired last night.

All axles use 75W-140 oil except for Dana 60, 70 and 80 unless it has 4.10 gears.

So you have a 60 with a 3.73. That is 80W-90. I meant to write that.

If you lift up the back end of the van with both wheels off the ground and spin one wheel, and both wheels spin it is Traction Lok, if not then it is worn out or an open differential