Rear diff cover

[HS108]

Does that Ford cover look thick enough to tap for a drain plug?

I could always get a chunk welded on at work but it'd be really nice to be able to drain it without removing it.

Its pretty thick. Idk about a drain plug, maybe, but it will only catch a couple threads

 

[Hydro-idi]

Or you can just drill a hole, smooth out the burs and install a Dana 35 differential cover plug. They also have these available at Azone.

https://www.summitracing.com/parts/...MIu-6p9JCL2QIVE4J-Ch0cOgEHEAQYAyABEgKpy_D_BwE

 

[Garbage_Mechan]

I just drill a hole for 1/4" pipe threads in the diff housing straight up the the bottom. My old fleet of F250 to FSuperduty had this done at the first oil change. Just use an Allen head plug and tap it deep enough to be flush or slightly below.

 

[Garbage_Mechan]

Housing drills very easily. The ones I did personally I used a small jack or a block and prybar to turn the drill into an upside down drill press.

 

[chillman88]

I just drill a hole for 1/4" pipe threads in the diff housing straight up the the bottom. My old fleet of F250 to FSuperduty had this done at the first oil change. Just use an Allen head plug and tap it deep enough to be flush or slightly below.

I never would have thought of that but it sounds like a great tip. Thank you!

 

[Garbage_Mechan]

On the gear oil..... remember over the years oil developed ang got much better and drain intervals were extended. On the 75w vs 85w in my head I can hear the departments arguing at Ford: Fuel mileage department: We want to run 75w gear oil to improve MPG.....axle department: let us run some wear tests. Months later axle dept: don't like it but we can get by......,,,mileage dept.....ok we are doing it!

 

[Garbage_Mechan]

And now years later we are still arguing about it. I would run either but prefer the 85w-140 syn. Never had leaks develop after the change Must have done 50 pairs of tandems on the truck fleet.

 

[Thewespaul]

Use what’s on clearance.

How often you change it makes more of a difference than the brand or weight.

 

[03wr250f]

Personally I’m not a fan of royal purple. I used to run it in difs. I did some reading on it in at least one oil viscosity study (no there’s no way I can find it now) and it didn’t even come close to maintaining viscosity. Way too thin at temp. That may be why you were seeing leaks. Mobil 1 was right near the top of the heap so that’s what I’ve been running. No leaks that I can see.

For the record, I run that ford diff cover with a gasket and rtv on both sides of the gasket. Just the way I was taught. Never had one leak though. I tend to use permeated ultrablack. It’s good for about anything.

I found the article I believe you were referencing
http://www.lastgreatroadtrip.com/wp-content/uploads/2010/11/gear-oil-comparison.pdf
I also posted a thread about it so others can find and read it.

 

[laserjock]

The RP is not much of any cheaper than the mobil 1 so I just stick with it. It’s done well in my gasser crank cases so far.

 

[austin92]

When I built a 10.25 for my 83 I put an undercover fab works diff cover on. It’s made out of 1/4 steel and with a drain plug it was like 140$. Also running a lube locker. It’s nice to reuse when I had to check on the new gears a few times



http://www.undercoverfab.com/fabric...rling-1025-105-rear-hd-diff-cover-welded.html

 

[rwk]

I like what Garbage mech said, drill the diff bottom, there is quite a bit of oil that sets in those casting pocket, when I change oil I have to soak it up with a rag, all the crap goes there also.