cornfed89

hey yall its been awhile since I've been on here (went the diesel route for awhile) but just picked up a 2006 f150 screw 4x4 and couldn't be happier! Well that's until I looked under my truck earlier after noticing what sounded like a popping or grinding noise when my tires spun for a second. There is fluid all over the left side of my diff cover (non on the front of diff or anywhere else) there was also what looked like red rtv all over where I would expect a drain plug to be. I pulled the hardened red **** off and the diff cover seems thin there??? Also the last week or so I have heard a humming that I thought was possibly a wheel bearing but after shaking the tires while installing my leveling kit last weekend seems more likely it may have been the rear end. Any help or suggestions are greatly appreciated I am working out of town and tryin to research on my phone but not finding much.

Toshbar

There is no drain hole on factory covers. All I can suggest is to remove the cover, inspect gears, change fluid, and seal it back up with good oil-resistant RTV.

cornfed89

Thank you! Will do tomorrow after work and see what happens. What should I look for other than cracks in the cover and chunks in the fluid?

Toshbar

I don't know what kind of experience you have so here are some tips:

Make sure to scrape all the old sealant off the cover lip, and to let the new stuff 'tack up' between when you squirt it around the diff cover flange and when you mate it back to the housing. There is a depression in the housing at the bottom that will hold a little bit of fluid check there for chunks and metallic sludge. I hosed mine out with a few cans of brake cleaner, just make sure to let it all evaporate off the gears and get as much out of the bottom with paper towels/rags as possible so it doesn't cut the gear oil. Also, if you have a limited slip, get some friction modifier, even if the oil you get says it is built in. I used Valvoline synthetic in my diffs this spring and needed to put 6 oz of friction modifier in to stop the chatter around sharp turns.

Check the carrier for play in bearings, chipped, cracked, or severely worn ring gear and spider gear teeth. It's going to be pretty hard to eyeball an out of alignment ring and pinion.

goodburbon

Good advice here. I run a Ford tear end in my jeep and it leaked the first few times i dug into it and replaced the gears, carriers etc. The final solution was to put a good bead of RTV around the perimeter and loosely bolt the cover on so that the Cover made contact all the way around but wasnt squeezing the RTV out. I let it dry and then torqued it all up several hours later before filling. I have havent had a rear diff leak in years, and the cover is a bit bent from being drug over a rock or two. I imagine that letting it tack up before mounting would be similar.

cornfed89

I appreciate it! I got the leak fixed (it was the diff cover leaking as they tried to ghetto rig repair it with some kinda plaster like crap) I put 2.5 quarts of royal purple and some friction modifier from advance auto in it. $120 later it makes two clicks when I take of from a dead stop! There where no shavings in the diff or any gunk etc...it actually looked a lot better than I expected. Are the two clicks the clutches in the limited slip? Could this be from using the advanced auto modifier instead of fords? What are my options at this point?

Toshbar

Are you turning or going straight when the clicks happen? If straight, it's not the clutches/FM.

How did all this cost $120?

cornfed89

Because I got a new cover for it as well ($30). And I did a gasket and rtv which was a little extra. But it clicks occasionally regardless of straight or turning.