2nd Gen Non-Engine/Transmission Rear differential leaking after fluid change...

[tbrudder]

Well, I finally got around to changing my differential fluid, using the directions on this excellent forum. Went with the Royal Purple (surprised to find it was, indeed, purple) 75W-90 (the only distributior around here didn't have the -140, and I don't tow heavy too much, anyway).



Anyway, the AutoZone (yeah, I know, I know... ) was out of the red and orange RTV, but they had some blue stuff, so that's what I used. I'm not exactly sure it's RTV, though. The package said it was good for use on differential covers, and needed no curing time.



However, I noticed a spot of oil under the rear differential this morning, and there's oil seepage on the bottom of the cover. Also, the blue 'goo' (for lack of a better word) that was squeezed out the side is still, um, gooey. It hasn't solidified.



So, a few questions, if you please...



1) Anyone know what this blue stuff is (I don't have the tube anymore), and whether it's really suitable for this application?



2) If it is suitable, could I possibly have used too much, or is it normal to squeeze some out?



3) How critical are torque values here? I managed to break my torque wrench a few weeks ago, and haven't gotten another yet. I've heard 30 ft-lbf; could overtorquing cause a problem?



4) Anyone know of a way I could make it stop leaking without taking the cover off and doing it again? Yeah, I'm not really counting on it, but I thought I'd ask. I guess I can siphon out the oil into a clean container so I can reuse it, then pull the cover off and reseal it, but if I can get away with something easier...



Fluid level's still good, so it appears to be a slow leak. It'll annoy the (*&# out of me until I get it stopped, though.



Thanks, all.



--Ty

 

[DavidC]

I changed mine a few months ago and skipped the RTV section and used Permatex Anaerobic gasket maker. It is a little pricey and could only find it at Napa. Between the permatex and the spray primer that activates it was $32. 00. Torqued the cover and added the RP fluid, no leaks. I think you will have to drain and reseal and I would recommend the Anaerobic and a torque wrench. Synthetic gets pricey after a while. One last note I tried autozone, checker and pep boys, they never heard of the anaerobic and thought it may have something to do with PE class



Dave

 

[Texas Diesel]

Any oil residue on the cover or diff housing will result in a leak. I know of no way to stop a leak like this without redoing it.



I use the grey silicone, AutoZone here carries it, no probs with many seal jobs.



Take her to the carwash, clean the diff and the area above it, go home and spray it with carb cleaner and wipe dry. Get a clean pan and drain the lube into the pan, set it aside and remove/reseal the cover, make sure you use enough (1/16"-1/8") bead.



The most difficult part will be finding a way to pour the lube back into the diff.



You made a good choice in lube



Make sure the surfaces are completely oil free before applying the sealer. PM me if you want to talk on the phone for other tips.

 

[illflem]

I use the Permatex Anaerobic gasket maker, it may be pricy but one tube will do at least 25 covers and it keeps, won't harden in the tube.

Some folks let the RTV type sealers dry for 24 hours before filling with oil, seems like a hassle to me, the Permatex is ready to go right away. Never had a leak.

 

[krs]

Back to your questions:

The 'blue stuff' - does "Permatex" sound familiar to you? If so, permatex blue is usually a fine sealant but it does require some air time before mating the parts as I recall. Whatever you use, read the directions and follow them.

Yes, torque is pretty critical. At the least there should be an even application of it all around the part. On differential cover bolts I'd think that 18 ft. lbs. would do. Having stuff squeeze out is normal.

Did you put your sealant all around each bolt hole and did you put a dab of it on the end of each bolt before you stuck it in the hole? If not. these are good tips. for next time.

Though it's very unlikely to help you could try removing each bolt in turn, smearing it liberally with sealant, and then putting it back in before going on to the next.

 

[Rman]

I always let mine sit over night before adding any lubricant, I've never had a leak before. I put my mag-hytec on and used a small amount of sealant and let it sit over night as well, not a drop. Torque is important, more so the eveness of the torque.

 

[tbrudder]

Thanks for the help, guys.



The blue stuff may well have been Permatex--I don't recall exactly, but I do remember it said it needed no curing time before mating.



Looks like I'll be pulling the cover off and redoing it this weekend with either the gray or the anaerobic stuff.



I'm thinking my problem might be oil on the mating surface (thanks, Tejas!). I thought I got it clean, but it was getting dark when I finished the job. Maybe the carb cleaner will help. Am I right in thinking I should avoid getting this stuff inside the differential?



Now I just hope I can manage to get the lube back in once I'm done...



Thanks again, all!

--Ty

 

[GWHaley]

For cleaning the old oil off the cover, I only use brake cleaner. Carb cleaner can be nasty on the hands and lungs, besides I find brake cleaner works better anyway (this type job is what it was designed for) and it doesn't really matter if you get some inside.

Go to your auto parts store and get a suction gun (looks like the tube from a grease gun). This is the cheapest and least messy way to get the oil back in the diff