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Changing Differential Fluid?


HRTKD

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So how exactly are you guys changing the differential fluids? I crawled under mine yesterday to do it but I couldn't find a drain plug on either the front or rear differential. I could drop the cover on the rear differential but then I would have to replace the gasket. :(

I could only find the fill plug on the transfer case. Is there really a drain plug on that?

While I'm at it I wanted to say thanks to the guys that posted info about the limited slip rear differential losing it's ability to do its thing. I looked up the codes on my rear diff and thought that either someone had removed that feature from mine or the codes were wrong. I guess it's just worn out. What is the best option for getting that corrected? I have an e-locker in my Nissan Titan and I love it. How tough would it be to get the same thing in the Ranger?
 


michowski

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The rear axle you have to remove the cover to drain the fluid. The transfer case and transmission both have drain plugs. The front diff has to be manually emptied. It only has a fill plug so you will need a syphon to get the fluid out. Obviously the drain plug is near the bottom of the rear differential. Its not a nut screwed into it either. Well it is but the head is square so all you need to do it just put your ratchet on there how it is.
 

MAKG

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On some models, the transfer case drain plug is hidden behind a damper. It comes right off with four bolts.

The plug is always on the back of the transfer case, at the lowest spot.
 

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for the differentials there are no drain plugs. you have to pull the diff cover for it. on the front you can use a cheap siphon pump to get the fluid out with out unbolting the pig from the beam. on the Tcase, there is a drain plug, sometimes it is just hidden by a steel thing that has a rubber grommit in it and bolts to the back of the case. i think its a vibration dampener but i am not sure.

i posted a few minutes ago to your thread in the introductions forum. with all the little stuff that you will be doing i would highly recommend a chilton manual or haynes manual for your truck. basically its a book that has every possible do it yourself item covered in it. you can get one at most parts stores.

about your L/S diff. i just repacked mine in my 97 with 108K on it. it was so bad before i did it that i could jack the back end up, put my truck in gear with the engine running and easily stop one tire with my shoe. now that i repacked it with some clutchs out of another axle, with it in gear with the engine off and the rear jacked up, no parking brake, i can torque my lugnuts with a breaker bar and it does not slip. it will wear out again and more quickly this time because i used clutches that were not new but it will be fine for me until i put a different axle under there. check out the tech library for the write up on repacking a L/S.

if you want a locker, you have 3 types. automatic, selectable, and solid.
a solid one is either a "Lincon locker" where the spidergears are welded together and to the carrier or a full spool that serves the same purpose and replaces the carrier or a mini spool that just replaces the spiders.
an automatic locker is one that has a ratcheting mechanism in it so that it can slip when your turning and are not on the gas and will lockup as soon as you give it gas. lock-right, detroit and aussie all make automatic lockers. most automatics replace the spiders but one of the two that detroit makes replaces the carrier. the replaces the spiders.
a selectable locker is one that you can turn on and off like the e-locker in your titan. the one made my OX is manual and has a shift lever that mounts in the cab. ARB lockers are operated by air. this means that they need some type of compressor to go with them. E-lockers are electronicly operated. then there is the Ected locker/limited slip which is made by Auburn. this one is again an electric locker but it also has the L/S feature when unlocked.

lockers are not cheap though. welding or spooling is the cheapest but if you have a daily driver then you will not want to do either of those. automatics are about 200-300 dollars and alot of people like them for the price. selectables are really nice but they are expensive both in initial cost , 600-900 dollars and in the installation cost because the gears need to be set up again because selectable lockers replace the carrier. gear setup can be 150-300 dollars.

wow that was a long post. did i answer all of your questions?

EDIT: wow it was so long that two other ppl answered before i did. MAKG confirmed that that thing i talked about on the Tcase is a dampener.

michowski, our rear diffs dont have drain plugs. fill plugs yes obviously but no drain plugs.
 
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HRTKD

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On some models, the transfer case drain plug is hidden behind a damper. It comes right off with four bolts.

The plug is always on the back of the transfer case, at the lowest spot.
OK, I saw the "damper" (didn't know that was what it was) and I'll see about removing that.

Hey, I used to own a '72 chevy pickup. Mine was a heavy half ton 4x4. Sounds like we had the same color.
 

HRTKD

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for the differentials there are no drain plugs. you have to pull the diff cover for it. on the front you can use a cheap siphon pump to get the fluid out with out unbolting the pig from the beam. on the Tcase, there is a drain plug, sometimes it is just hidden by a steel thing that has a rubber grommit in it and bolts to the back of the case. i think its a vibration dampener but i am not sure.

i posted a few minutes ago to your thread in the introductions forum. with all the little stuff that you will be doing i would highly recommend a chilton manual or haynes manual for your truck. basically its a book that has every possible do it yourself item covered in it. you can get one at most parts stores.

about your L/S diff. i just repacked mine in my 97 with 108K on it. it was so bad before i did it that i could jack the back end up, put my truck in gear with the engine running and easily stop one tire with my shoe. now that i repacked it with some clutchs out of another axle, with it in gear with the engine off and the rear jacked up, no parking brake, i can torque my lugnuts with a breaker bar and it does not slip. it will wear out again and more quickly this time because i used clutches that were not new but it will be fine for me until i put a different axle under there. check out the tech library for the write up on repacking a L/S.

if you want a locker, you have 3 types. automatic, selectable, and solid.
a solid one is either a "Lincon locker" where the spidergears are welded together and to the carrier or a full spool that serves the same purpose and replaces the carrier or a mini spool that just replaces the spiders.
an automatic locker is one that has a ratcheting mechanism in it so that it can slip when your turning and are not on the gas and will lockup as soon as you give it gas. lock-right, detroit and aussie all make automatic lockers. most automatics replace the spiders but one of the two that detroit makes replaces the carrier. the replaces the spiders.
a selectable locker is one that you can turn on and off like the e-locker in your titan. the one made my OX is manual and has a shift lever that mounts in the cab. ARB lockers are operated by air. this means that they need some type of compressor to go with them. E-lockers are electronicly operated. then there is the Ected locker/limited slip which is made by Auburn. this one is again an electric locker but it also has the L/S feature when unlocked.

lockers are not cheap though. welding or spooling is the cheapest but if you have a daily driver then you will not want to do either of those. automatics are about 200-300 dollars and alot of people like them for the price. selectables are really nice but they are expensive both in initial cost , 600-900 dollars and in the installation cost because the gears need to be set up again because selectable lockers replace the carrier. gear setup can be 150-300 dollars.

wow that was a long post. did i answer all of your questions?

EDIT: wow it was so long that two other ppl answered before i did. MAKG confirmed that that thing i talked about on the Tcase is a dampener.

michowski, our rear diffs dont have drain plugs. fill plugs yes obviously but no drain plugs.
Thanks for all the great information. I have used the Chilton manuals before and I'll have to pick one up for the Ranger.

I have a siphon that I normally use to get diff fluid out of the bottle and into the differential. I suppose I can use it to go the other way also.

I guess since the clutch plates are fried on the rear differential there is no need to put the friction modifier in there, right? I'm going to be putting in synthetic 75w-90 to both front/rear. I have 5 unopened quarts of it already.

Can you give me a price range on replacement clutch plates? And how tough is it to do? I haven't opened a differential since shop class in high school (26 years ago!).

In the Titan community the Detroit TrueTrac is well thought of. But around here it sounds like Lock Right is the most popular. I'll have to check that out. For a change like that I would probably take it to someone else to have it installed.
 

metalmacguyver

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here is a rebuild kit.
http://store.summitracing.com/partdetail.asp?part=FMS-M-4700-B&view=32&N=700+

its not too hard to do. i did mine in about 3hours total and it was my first time going into a L/S. that write up in the tech library was very helpful and reordering the clutches like it mentioned makes it much tighter. i really like it. also i am using no friction modifier because i want my diff to be as tight as possible. it may wear out faster but i dont care.

the detroit is in many circles the god off lockers for durability and reliability. however around here, with most of us being less hardcore than those on pirate, the lock right is prefered for its ease of installation and price.

if you think your up to replacing the clutch packs in your L/S, then your equally able to install a Lock Right. this has lots of pictures in it. --> http://www.4lo.com/94jeep/lock-right-d35c/install.html
 

HRTKD

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I got the front and rear differential fluids changed today. That was a royal pain in the butt. The front wasn't too bad - siphoning out the fluid is odd - but the rear was difficult. The gas tank blocks the access to the fill plug so I had to use a pump and hose to get the new fluid in there. The hose was wedged into the fill plug so tight that I over filled the rear differential. I had to wait around a while for it to drain off before I put the fill plug back in.

However much the dealer charges for replacing the differential fluids, it's not enough money. Next time I'll let them do it.

Next up, changing the transfer case fluid.

FWIW, I doubt the differential fluids were changed within the last 100,000 miles.
 

metalmacguyver

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what i usually do to change the diff fluid is jack the truck up and put the jack stands on the frame so that the axle droops down and it gives alot more room and access to the fill plug.
 

HRTKD

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what i usually do to change the diff fluid is jack the truck up and put the jack stands on the frame so that the axle droops down and it gives alot more room and access to the fill plug.
Ya know, I thought of that about half way through filling the differential. By that time my gloves were messy enough that I didn't want to have to get on another pair. I did have all four wheels on jack stands already, but just to give me a little more room underneath.

Is there much danger in overfilling the differential? There was some information on the AMSoil web site that indicated that the level was to be 1/4" below the drain plug. When I have changed differential fluids on other vehicles it was alway fill it until it just starts to come out the fill plug.
 

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100,000 miles (depending on what year yours is) is the recommended interval for the differential fluid (those with the factory synthetic fluid).

No actual danger in overfilling an axle. The most that'll happen is a little bit may blow out of the breather tube, creating a bit of a mess.
 

HRTKD

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No actual danger in overfilling an axle. The most that'll happen is a little bit may blow out of the breather tube, creating a bit of a mess.
Thanks for the assurance. That brings up a question. Do you guys do the Axle Vent Mod?
 

HRTKD

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At least on the Titan there is a vent on the axle that allows pressure build up to be released without causing the seals to blow out. At least that is what it is _supposed_ to do. The vent can get damaged or dirty and get stuck either in the open or closed positions. Both are bad. The solution is to run a hose from the axle vent up into the tail light assembly with a fuel filter on the end of it to prevent water/crud from going into the axle. Many Titan owners have done this mod and credit it with preventing axle seals from blowing out and causing the differential fluid to leak. It's a cheap $15 mod that I think may have originated in the Jeep community.

I have done this on my Titan. Here is the writeup I did on it:
http://mightytitans.boardnation.com/index.php?topic=765.msg17719#msg17719
 

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Fords come factory with a vent hose already on it. It doesn't go quite as high as up to the taillight, however that's just a matter of pulling off the stock hose, and shoving a new longer one over the fitting.
 

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