changing rear diff fluid
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Fleet Mechanic
Joined: Sep 2007
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From: down south
changing rear diff fluid
Is the only way to drain the old stuff to crack the back cover? That would require a new gasket and didnt want to open it up if I didnt have to. See the refill hole, but not a drain. Am I seeing this right?
Senior User
Joined: Nov 2003
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From: northern Illinois
Some people use a siphon hose through the filler hole, but the best way is to take off the cover. There is usually no gasket there anyway. It usually has a bead of RTV silicone around the mating surfaces. I always like to take the cover off, so I can clean out any sludge that may have accumulated in the bottom of the diff. That said, sucking the old fluid out through the fill hole is still better than leaving the old fluid in there.
Senior User
Joined: Nov 2003
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From: northern Illinois
I've used some brakleen around the gasket surfaces and on a rag to wipe the bottom of the diff off, but I would be leery of hosing everything down with any solvent. Probably just best to wipe out whatever you can off the bottom or other easy to get to spots. The biggest trick in this job is getting the sealing surfaces clean so you can put some fresh RTV on them and not get any leaks.
Cross-Country
Joined: Oct 2005
Posts: 93
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From: SE Michigan
RTV with Synthetic Gear Lube
My parts guy recommended using a gasket rather than RTV with Synthetic. He said that the synthetic lube broke down the RTV. So I used a gasket, no leaks so far...
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Tuned
Joined: Jun 2003
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From: poughkeepsie ny
Weirdly, I used a gasket on my '94 and it leaked anyway. Mating surfaces looked smooth, I coated both sides of the gasket with oil and I followed the recommended torque pattern. Only way I could get a leak proof seal was to use the RTV (like the pan had when I took it off). BTW, if you do use RTV, make sure to follow the directions on the package to the letter.
Like dart7383 said, it'd probably be best to steer clear of using any solvents in there. Change the oil once you've driven around for a good long while so it's nice and warm, and use that rag if there's any junk that doesn't drip out. Change the oil again in 3k or so, if you think you've missed any of the goo.
Like dart7383 said, it'd probably be best to steer clear of using any solvents in there. Change the oil once you've driven around for a good long while so it's nice and warm, and use that rag if there's any junk that doesn't drip out. Change the oil again in 3k or so, if you think you've missed any of the goo.
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Fleet Mechanic
Joined: Sep 2007
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From: down south
Mine looks nothing like that!
Senior User
Joined: Jan 2006
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NewportNic, What breaks down the RTV is "Friction Modifier". Permatex just came out with a RTV that is not affected by this. I have not been able to find it in stores yet but it is on their site. It has some Green rings on the tube.
