Rear Differential Fluid
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Rear Differential Fluid
I have a 2000 Ford F-150. It has over 100,000 miles on it. I am going to be changing the rear differential fluid. I purchased the Mobil Synthetic recommended.
My question is, since it has never been replaced, should I take the rear cover off and completely drain it that way, or would pumping it out do the job just as well? I've never had any problems, noises, binding etc...
scott
My question is, since it has never been replaced, should I take the rear cover off and completely drain it that way, or would pumping it out do the job just as well? I've never had any problems, noises, binding etc...
scott
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Joined: Nov 2007
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From: Michigan
according to my haynes manual it says to pump it out.
I recently had to replace my rear axle seals and it won't hurt to open up the rear end, drain the fluid wipe it clean on the inside, inspect for unusual wear in there and this insures that you get all the old liquid out. Mine came out a milk chocolate color.
To take off the diff cover use a razor knife to cut out the old rtv after all the bolts have been removed. this of course is after you warm up the rear end. after 3/4 of the rtv has been cut razor knife deep around the cover should pull of the rearend without being bent or anything. when putting it back together just clean the surface of the axle and diff cover and apply rtv around the rear axle housing. torque the bolts to i believe 23 ft/lbs. (not very much) and you'll be set to add fluid which i thought was the hardest of things because you have to fill it sideways.
be sure to check for friction modifier in the oil and add accordingly. good luck.
I recently had to replace my rear axle seals and it won't hurt to open up the rear end, drain the fluid wipe it clean on the inside, inspect for unusual wear in there and this insures that you get all the old liquid out. Mine came out a milk chocolate color.
To take off the diff cover use a razor knife to cut out the old rtv after all the bolts have been removed. this of course is after you warm up the rear end. after 3/4 of the rtv has been cut razor knife deep around the cover should pull of the rearend without being bent or anything. when putting it back together just clean the surface of the axle and diff cover and apply rtv around the rear axle housing. torque the bolts to i believe 23 ft/lbs. (not very much) and you'll be set to add fluid which i thought was the hardest of things because you have to fill it sideways.
be sure to check for friction modifier in the oil and add accordingly. good luck.
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I would agree to pull the cover and completely clean it out with brake parts cleaner real good. As papajoemrt said, use a razor if need be and clean all old sealant off. Make sure to reaply and then to add a bottle of friction modifier even if the oil has it in it! Good luck!
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From: Michigan
Keeping the diff cover straight is vital so it doesn't leak in the future, hence the razor knife. use brake parts cleaner but i wouldn't want to get that stuff in the clutches if you do have a LS rearend. ford's recommends adding 4 oz. of friction modifier if you were looking for an amount.
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I really appreciate the replies. Very good info...
I have a Haynes manual, and it says its ok to pump it out. I just wondered if that was the best course of action, since I had never changed it. It's never leaked, which is why I considered just pumping it out.
I did get the friction modifier, and was told to add it all in first, to make sure all that got in. I also read to make sure and get the filler plug out before taking the cover off. It seems that they get stuck in there some times, and of course not being able to refill it, would be a problem.
Any trick to using the rtv to reinstall the cover? Would a gasket be better?
I have a Haynes manual, and it says its ok to pump it out. I just wondered if that was the best course of action, since I had never changed it. It's never leaked, which is why I considered just pumping it out.
I did get the friction modifier, and was told to add it all in first, to make sure all that got in. I also read to make sure and get the filler plug out before taking the cover off. It seems that they get stuck in there some times, and of course not being able to refill it, would be a problem.
Any trick to using the rtv to reinstall the cover? Would a gasket be better?
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From: Michigan
it's ok to pump it out but in my opinion removing the cover is the better way, that way you get it all out of the bottom, if you open it up you'll see.
make sure that it comes out and if it doesn't then spray it with some people on here call PB blaster or something that's made to unfreeze rusted parts.
i don't think there is a gasket for it, may be i'm not sure but rtv is cheaper and won't fail if put on correctly later down the road. use the rtv sealant that comes in a caulk tube, throw it in the gun, cut the tip on a bit of a slant but not too big (pencil sized hole). go around the axle housing, inside or outside the bolt holes in a continuous stream of sealant. then go back and go around the bolt hole.
hope this helps. I don't remember what kind of rtv i used but it was black in color. place the cover back on after cleaning it. torque the bolts in a criss-cross fashion like you would when you torque a wheel. then clean the rtv from the outside of the cover then you'll be set.
make sure that it comes out and if it doesn't then spray it with some people on here call PB blaster or something that's made to unfreeze rusted parts.
i don't think there is a gasket for it, may be i'm not sure but rtv is cheaper and won't fail if put on correctly later down the road. use the rtv sealant that comes in a caulk tube, throw it in the gun, cut the tip on a bit of a slant but not too big (pencil sized hole). go around the axle housing, inside or outside the bolt holes in a continuous stream of sealant. then go back and go around the bolt hole.
hope this helps. I don't remember what kind of rtv i used but it was black in color. place the cover back on after cleaning it. torque the bolts in a criss-cross fashion like you would when you torque a wheel. then clean the rtv from the outside of the cover then you'll be set.
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NOTE:
the filler plug is magnetic so when you remove it be sure to clean all the junk from it and then put the cover back on with the rtv. shouldn't have any leaking problems. my oil wasn't very dirty but there was a film of crude on all the inside parts. I washed with a mild solvent. Like papajoemtr said it takes longer to refill than to empty and clean out.
the filler plug is magnetic so when you remove it be sure to clean all the junk from it and then put the cover back on with the rtv. shouldn't have any leaking problems. my oil wasn't very dirty but there was a film of crude on all the inside parts. I washed with a mild solvent. Like papajoemtr said it takes longer to refill than to empty and clean out.
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From: Michigan
i must add that according to your owner's manual that the differential fluid is considered "lubed for life" as long as there are no leaks, if the rearend hasn't been submerged in water, or the rear end doesn't need service.
the reason i did mine for example was because the rear axle seals were bad requiring me to change fluid. i had the same mindset you had, getting old start changing some fluids because it can't last forever, well i ended up changing it anyways.
hope it goes well, just thought i'd mention that.
the reason i did mine for example was because the rear axle seals were bad requiring me to change fluid. i had the same mindset you had, getting old start changing some fluids because it can't last forever, well i ended up changing it anyways.
hope it goes well, just thought i'd mention that.
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dont believe any manual that says the original oil is "good for life". the gear lube dont wear out, but the crud setting on everything and the magnet is not good. take the cover off and wire brush the face. clean the insides with solvent and dry. put a bead of RTV on the face of the cover and bolt it on square. using a piece of plastic tube about 8 inches long on the tip of the new lube bottle will help get it into the pipe plug fill hole. You can get the friction modifier at Auto Zone, comes in a 7 oz bottle, add the whole thing.
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I think it best to open it up all the way (which is what I did) and to stick a strong, but small, magnet into every crevice after draining. Brake cleaner sonds like a good idea, then, too, but you're adding a small amount of time for that big of an area to allow the brake cleaner to evaporate off.
On one 8.8" rear end I did I got a LOT of metal on the magnet, but on the last 8.8" I did I did not get so much.
I went with Mobil 1 Synthetic rear-end fluid (there are two weights - get the correct one for your Ford), but no friction modifier... well - that was a mistake. I lived without posi-traction (or whatever ford calls it) for a long time until it all started working again. Use a 4 0z. tube with Mobil 1 and, hopefully, it will work better than mine did for two years, lol.
On one 8.8" rear end I did I got a LOT of metal on the magnet, but on the last 8.8" I did I did not get so much.
I went with Mobil 1 Synthetic rear-end fluid (there are two weights - get the correct one for your Ford), but no friction modifier... well - that was a mistake. I lived without posi-traction (or whatever ford calls it) for a long time until it all started working again. Use a 4 0z. tube with Mobil 1 and, hopefully, it will work better than mine did for two years, lol.
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From: Southeast FLA
Let me clarify that magnet - I used a typical mechanic's magnet on the antenna-type extension to get into those tight places.
I also used a new gasket that I smeared an RTV gasket stuff on both sides of but, while it has held it at an acceptable level for years - there is a little darkening of the bottom of the pumpkin from some seepage. How it can look like it isn't a tight seal, but never leak out any appreciable amount over years, is beyond me. Still, you may want to try just a gasket and gasket prep (which does not dry up like RTV gasket maker), or just an RTV gasket sealant.
Any of you guys actualy do the job and never, ever, have some darkening of the bottom from some seepage? If so, what method did you use to seal it up?
I also used a new gasket that I smeared an RTV gasket stuff on both sides of but, while it has held it at an acceptable level for years - there is a little darkening of the bottom of the pumpkin from some seepage. How it can look like it isn't a tight seal, but never leak out any appreciable amount over years, is beyond me. Still, you may want to try just a gasket and gasket prep (which does not dry up like RTV gasket maker), or just an RTV gasket sealant.
Any of you guys actualy do the job and never, ever, have some darkening of the bottom from some seepage? If so, what method did you use to seal it up?