So I recently picked up my '99 SD F250 with the 5.4L/4R100 4WD combo. Today was oil change day, normally not a big deal. But today it was (is).

At first I notice the oil filter is a bit tight, no worries I just keep working on it - I have NEVER been unable to change a filter by hand only. But today that changed... No big deal, poke a screwdriver through and no dice just starts tearing. No big deal, hit up NAPA grab one of their fancy little 3-arm filter wrenches- and no dice, in fact the damn thing breaks. No big deal grab a pair of filter filter channel lock type thingies and money! Manange to work the filter off.

Obviously at this point I'm a bit frustrated and concerned the threads may be a bit screwed up or the PO put the wrong filter on. Throw the FL820S up there and she spins right on... ALMOST. About 1/8in from the top it stops. Feels like I could force it with a socket or channel locks, but lets not do that. Threads look fine to crossthreading or rolled threads so I figure that somebody must have changed the filter adapter out at some point in time to something VERY close to stock but just not quite right.

There is an internal hex key spline I could use to unbolt the actual filter fitting (the tube) but I only have metric allens up to 11mm and this is somewhat bigger. So that leads to my two questions.

1. Does anybody know what size allen wrench I will need to remove the oil filter mounting tube?

2. What are is the stock thread size supposed to be?

At this moment I've spent about 5hrs between actually crawling around under the truck and running back and forth to the parts store through construction so I'm very much thinking "BOHICA" and I would just like to get this wrapped up. Any help is much appreciated!

 

I happened to change my oil today too ironically. Since i started doing my own oil i have always needed one of those filter wrenches. mine also screwed all the way up to the top before it started to get tight. Will it not move once you get 1/8" from the top or is it just hard to move?

 

Well, problem solved. No idea what the problem was, but I removed the mounting insert, dropped the cooler adapter and reinstalled everything and the filter went right on.

 

the filter adapter could have been sized incorrectly
Good job !