Diff Fluid Change

[chefduane]

Good advice, to be sure. Rear shoes have already been done and I had a right axle seal done a few years ago. Left one is still holding.

 

[ccm2001]

Just go t Ford and buy the XL3 FM its only 5$ BTW keep it in a bag it really does have a heavy odur like Trans fluid

 

[rb142]

There's a lot of suspicion with the use of RTV in place of gaskets and rightly so if you've seen some of the messes out there from using it incorrectly.

I use it all the time and don't have problems, that's because I put a bit of thought and care into it.

How I do it is -
clean both mating surfaces,
apply a bead of RTV to the movable surface (the diff cover)
apply a thin coat of oil to the stationary surface
when the bead is "off" but before it sets, apply the cover to the diff and press gently making the bead form a gasket.
screw the bolts in just enough to hold the cover on without squeezing the RTV out - this step is very important.
when the RTV is set torque the bolts up.

You now have a silicone gasket that is formed in place and should come off the diff ok.

I agree completely. Good for you for doing it properly. Many people just goop it on, torque the bolts down, fill and go. This often results in the cover being glued on so hard that they have to chisel it off with a screwdriver or something, which then bends the lip and creates a leak.

I prefer to use a gasket, mostly because it is faster -- there is no waiting time while the rtv cures. That doesn't matter if one isn't in a hurry, but it does if it is your only vehicle. It's easy too, especially with the re-usable rubber gaskets. But RTV will do the job fine if done properly. RTV certainly is more common than the gasket approach.

 

[chefduane]

So I got the differential oil and cover changed...
Man!! How many thousand ft/lbs of torque do they put those cover bolts on with?? Had to break them loose with a rubber mallet! I had it changed about 75k ago and they used RTV and most likely an air wrench to torque them down. Real PITA to get them off. I scraped all the RTV off the mating surface and used the regular gasket that came with the Dorman cover. I also cleaned up all the bolts and threads with my bench grinder fitted with a wire brush. Everything went back together quite nicely. I also cleaned up the threads of the fill nut and used Loctite Red on them. Went with Valvoline 75w-140 Full Synthetic and the Sta-Lube EquaTorque Friction Mod. I used a cheapie Harbor Freight transfer pump and that worked out OK to refill the diff. I'll keep a look out for any leaks.

I did not do any of the other maintenance items that you all suggested.

But, I started the day by changing out the fuel filler tube. The plastic sleeve at the top was cracking and chipping quite badly and I was concerned that it could potentially get into the tank and foul the pump intake, so I changed it out. I also dropped the spare and pulled the cover for the Vapor Canister Vent Solenoid and opened it up and gave the solenoid a thorough cleaning. Really filthy and grimy. Been chasing an elusive P0442 code, and after tightening and swapping out some loose breather tubes I figured that the solenoid was next. If I can't get the code to clear at that point I'm thinking Canister Purge Valve under the battery.

Tomorrow is Transfer Case flush/fill (which I hope will go somewhat easier than the diff), and I also have to install a new Wiper Washer Pump that has crapped out (already checked electricals and relays).

I have Sat/Sun/Mon/Tue off so I'm gettin' done what I can while I'm out of the kitchen! Hopefully, Tuesday will be jacuzzi and cigars!! AND, I hope my hands don't stink of gear oil when I get back. Man, that stuff stinks BAD!! Don't wanna' serve any entrée that smells like gear oil!

..thanks for listening.

 

[rb142]

The diff cover bolts should only be 33 ft-lbs. They are usually way easier to get out than the fill plug.

I think you made a mistake putting Loctite Red on the plug. No need for that (blue would do fine). Good luck getting that out again. It will probably require a lot of heat.

Don't forget about the front diff while you are at it. People tend to neglect those, but they need changing just like the back.

 

[chefduane]

Loctite Red was on the plug when I removed it. Perhaps that's why it was a SOB to get off. I won't be changing it again for some time so I'll just deal with it then. As far as the front goes, I've had that done by my local shop. Front is a SOB all by itself and I'd rather just pay to have it done.

 

[rb142]

If it was factory, the red stuff on the plug was a thread sealant, not red thread locker. But it is possible someone put red locktite on it along the way. The plug won't go anywhere on it's own, so overkill just makes it harder to get out. If you are trying to undo one of those in the future, heat is the best (sometimes only) way to release red locktite. A very good example of that are the T30 torx bolts on the front driveshaft differential yoke. Those will either break or strip if you don't heat them.

 

[SoNic67]

A very good example of that are the T30 torx bolts on the front driveshaft differential yoke. Those will either break or strip if you don't heat them.

Mine came out with penetrating oil (PB Blaster) left there over night. They were not lock-tited from factory.
PS: I use only blue locktite on my screws, it's more "removable".