Rear Diff Fluid Chang Question

[Samm25]

I feel like I’ve been posting a bunch on here. So apologies if you’re getting tired of seeing my name haha

I had a question on my rear differential fluid change. Never done it before but looking to now. My ‘05 2wd has 191k on it. It’s running perfect. But I’m looking to change that rear diff fluid. I don’t drive the vehicle in extreme conditions or anything, nor have I ever done a transmission fluid change and I know the previous owner didn’t. I called a transmission shop the other day and he told me not to change it as long as I’m not getting to 220 degrees F on the Tranny Fluid because it will last the life of the vehicle in that sealed transmission. He said if I change it I could risk actually ruining the transmission.

So, my question is: does this have anything to do with the rear diff fluid? Is it sort of the same concept or does it have nothing to do with me risking damage to it since it’s never been done?

Thanks for the help

 

[JeffMerr]

I feel like I’ve been posting a bunch on here. So apologies if you’re getting tired of seeing my name haha

I had a question on my rear differential fluid change. Never done it before but looking to now. My ‘05 2wd has 191k on it. It’s running perfect. But I’m looking to change that rear diff fluid. I don’t drive the vehicle in extreme conditions or anything, nor have I ever done a transmission fluid change and I know the previous owner didn’t. I called a transmission shop the other day and he told me not to change it as long as I’m not getting to 220 degrees F on the Tranny Fluid because it will last the life of the vehicle in that sealed transmission. He said if I change it I could risk actually ruining the transmission.

So, my question is: does this have anything to do with the rear diff fluid? Is it sort of the same concept or does it have nothing to do with me risking damage to it since it’s never been done?

Thanks for the help

No fluid will last the life of a vehicle, especially a 4runner that lasts forever. You can always do a drain and fill, or series of drain and fills if you're worried about it. And no, the rear diff fluid is completely separate and should be changed if it hasn't in a while. Use a 75-90w synthetic gear oil.

 

[Samm25]

No fluid will last the life of a vehicle, especially a 4runner that lasts forever. You can always do a drain and fill, or series of drain and fills if you're worried about it. And no, the rear diff fluid is completely separate and should be changed if it hasn't in a while. Use a 75-90w synthetic gear oil.

Appreciate your response. I’ll look into both changes. I plan to do the diff myself because it’s easiest, the tranny id let someone professional do it

 

[Atlanta_man]

Be sure you can get the fill plug off first, before you drain it.

Couple years ago I had the shop drain and fill mine. Best $40 I ever spent.

 

[Bossman]

I'd recommend also checking on, and possibly replacing, your rear differential vent when you do the fluid change.

 

[99Runnr]

A transmission service at 191k is NOT a bad idea unless you just want to dump the vehicle. I changed mine at 160k and it was original, one was very dark and nasty an new dealer fluid is a nice red.

As mentioned, check both plugs at the rear differential before going fully into the project. You find level ground, pull the drain plug, remove fill plug while it's draining. Once it's done draining, replace drain plug, an fill differential housing through the fill plug opening. The truck should be on FLAT ground, you fill until it dribbles out. I believe rear diff is ~3.5 quarts.

As for transmission, it can be done by a backyard mechanic. It's tedious and messy as you are almost guaranteed to spill fluid somewhere somehow. The write up is out there an works great. Essentially you drain the pan, capture an measure fluid, re-fill transmission with same amount. Remove return line up by front radiator, start the truck, once you have captured 1.5 quarts, shut vehicle off an it will continue to run briefly up to about 2 quarts. Re-fill 2 quarts, re-start truck, quickly go through the gears with foot on the brake, park, reverse, neutral, down into drive, ect. Return to park, don't let the line spit out more then 2.5 quarts without shutting engine off and re-filling. Repeat this process until trans fluid on the return line is coming out clean. At that point, you get transmission fluid up to temp, an remove overflow plug on transmission pan. If it runs out, let it level out. If it doesn't run out, you are not full an add small amounts until it dribbles out.

It's just a process of remove and replace until you cycle out about 12 quarts of fluid. It is a 90k mile interval replacement fluid for majority of people. IE: Those who don't abuse/tow/constantly run their stuff hard. The lifetime fluid is a myth unless you don't care about maintenance or transmission longevity. Shop's like Toyota and independent transmission service, are often leery to use their pressurized flush equipment as it can dislodge debris an create problems internally. Doing the drain and fill at home is perfectly safe if you can understand remove 3.5 quarts, add 3.5, remove 2, add 2, an so on.

 

[Seymore Butts]

You should definitely replace both fluids. And find a different transmission mechanic who knows what he's talking about.

 

[Samm25]

See, that’s the idea I’m torn with. I have done MUCH research on the transmission fluid change and everyone has their own different opinion about it. Toyota tells me it’s a “life” long fluid as long as you’re not doing heavy driving such as towing a lot, off roading, etc. which I don’t. I have my scangauge and monitor my tranny fluid and it never gets above 170ish even in the Texas heat. I’ve called different mechanics and they all recommend NOT changing it, especially on a 2wd if I’m not abusing it.

According to what I’ve seen, the fluid in the transmission is rated up to 220 degrees until it starts to deteriorate, as long as you’re not running it over 220 often, I’ve been told by mechanics and Toyota that it should not be changed. Even on the recommended service manual from Toyota, it doesn’t recommend changing the tranny fluid unless you’re under those heavy load circumstances.

I’m just torn between what to do, because I’ve also been warned that if I change it at 191k and the fluid doesn’t sit right, it’ll cause my gears to start slipping therefore I’ll end up needing transmission service done.

Just torn between what to do with the tranny. Appreciate everyone’s help though!

 

[woodman60]

I’m just torn between what to do, because I’ve also been warned that if I change it at 191k and the fluid doesn’t sit right, it’ll cause my gears to start slipping therefore I’ll end up needing transmission service done.

Just torn between what to do with the tranny. Appreciate everyone’s help though!

I'm in this same boat. Nearly identical 191K mileage and no evidence from service records of tranny fluid ever being changed. I'm thinking of calling my three nearby Toyota dealers and seeing if there's a consensus.

 

[djkurious]

When a dealer says "lifelong" or "lifetime" fluid it means 4 years or when the warranty runs out. Then you trade-in your vehicle for another vehicle with "lifetime" fluid.

 

[AuSeeker]

See, that’s the idea I’m torn with. I have done MUCH research on the transmission fluid change and everyone has their own different opinion about it. Toyota tells me it’s a “life” long fluid as long as you’re not doing heavy driving such as towing a lot, off roading, etc. which I don’t. I have my scangauge and monitor my tranny fluid and it never gets above 170ish even in the Texas heat. I’ve called different mechanics and they all recommend NOT changing it, especially on a 2wd if I’m not abusing it.

According to what I’ve seen, the fluid in the transmission is rated up to 220 degrees until it starts to deteriorate, as long as you’re not running it over 220 often, I’ve been told by mechanics and Toyota that it should not be changed. Even on the recommended service manual from Toyota, it doesn’t recommend changing the tranny fluid unless you’re under those heavy load circumstances.

I’m just torn between what to do, because I’ve also been warned that if I change it at 191k and the fluid doesn’t sit right, it’ll cause my gears to start slipping therefore I’ll end up needing transmission service done.

Just torn between what to do with the tranny. Appreciate everyone’s help though!

Look at it this way, you have asked Toyota, you have asked other mechanics, but I can most likely assure you that most of who you have asked don't own or have ever owned a 4runner, most of these people are telling this because of the moniker "lifetime fluid" that my friend is a misnomer, there is no such thing as a "lifetime fluid" when it comes to a lubricate/oil, all lubricates loses their viscosity, additives degrades, etc.

That being said everyone here on this forum do own and drive 4Runners and most of us are saying to do the transmission fluid changed or at least a "drain and fill" which only replaces about 3 quarts of the 12 the transmission has in it, this advice is from experience of us doing exactly that, changing the fluid, we see what the old fluid looks like when we drain it out, almost always it's very dark to black, not what it should look like, and almost all have reported the transmission shifts much smoother and also seems to eliminate the torque conventer "Shudder" that many owners have had with their 4Runners, I don't recall anyone having any ill affects of the changing the fluid.

Toyota's maintenance schedule does indeed say to change the transmission fluid at 60,000 miles..IF it's been used for towing, or offroad etc., this in itself is very telling to me, it tells me the fluid does indeed degrade albeit the fluid is under a bit more heat, but degrade it does even under normal conditions.

I'm an old school mechanic, but I have kept up to date on the latest technologies, I have over 40 years experience in diesel and automotive mechanics, 20 to 25 years ago I would have given you the same advice on "Not Changing the fluid in a high mileage transmission", but the transmissions and especially the fluids of more modern times are not the same as they were back then, the fluids now don't leave the same deposits if any as they did back then, unless you let them overly degrade over time, those old fluids as they degraded over shorter periods of time then now-a-days left deposits A.K.A. sludge which could become dislodged in older high mileage transmissions when you changed the fluid and then could possibly clog the valve body which would prevent the fluid from going through the proper passages and could cause the clutch pack to burn out because of lack of hydraulic pressure to squeeze the clutch pack together tightly enough to prevent them from slipping and overheating, it could also cause improper shifting for the same reason, fluid not going where it should through the valve body, 25 years ago a high mileage transmission was around 80,000 to 100,000 miles, now days 250,000 to 300,000 or more.

I say all this not to convince you to do the fluid change but just a bit of FYI so you have more info to make the call to do it or not.

 

[Samm25]

Look at it this way, you have asked Toyota, you have asked other mechanics, but I can most likely assure you that most of who you have asked don't own or have ever owned a 4runner, most of these people are telling this because of the moniker "lifetime fluid" that my friend is a misnomer, there is no such thing as a "lifetime fluid" when it comes to a lubricate/oil, all lubricates loses their viscosity, additives degrades, etc.

That being said everyone here on this forum do own and drive 4Runners and most of us are saying to do the transmission fluid changed or at least a "drain and fill" which only replaces about 3 quarts of the 12 the transmission has in it, this advice is from experience of us doing exactly that, changing the fluid, we see what the old fluid looks like when we drain it out, almost always it's very dark to black, not what it should look like, and almost all have reported the transmission shifts much smoother and also seems to eliminate the torque conventer "Shudder" that many owners have had with their 4Runners, I don't recall anyone having any ill affects of the changing the fluid.

Toyota's maintenance schedule does indeed say to change the transmission fluid at 60,000 miles..IF it's been used for towing, or offroad etc., this in itself is very telling to me, it tells me the fluid does indeed degrade albeit the fluid is under a bit more heat, but degrade it does even under normal conditions.

I'm an old school mechanic, but I have kept up to date on the latest technologies, I have over 40 years experience in diesel and automotive mechanics, 20 to 25 years ago I would have given you the same advice on "Not Changing the fluid in a high mileage transmission", but the transmissions and especially the fluids of more modern times are not the same as they were back then, the fluids now don't leave the same deposits if any as they did back then, unless you let them overly degrade over time, those old fluids as they degraded over shorter periods of time then now-a-days left deposits A.K.A. sludge which could become dislodged in older high mileage transmissions when you changed the fluid and then could possibly clog the valve body which would prevent the fluid from going through the proper passages and could cause the clutch pack to burn out because of lack of hydraulic pressure to squeeze the clutch pack together tightly enough to prevent them from slipping and overheating, it could also cause improper shifting for the same reason, fluid not going where it should through the valve body, 25 years ago a high mileage transmission was around 80,000 to 100,000 miles, now days 250,000 to 300,000 or more.

I say all this not to convince you to do the fluid change but just a bit of FYI so you have more info to make the call to do it or not.

I appreciate your response and info. Definitely makes sense! You may have just convinced me to do it after all haha. I love the idea of getting it changed, just hate the one of possibly causing “damage” to it, but I guess I’ll never know unless I try it. And there’s never anything wrong with getting clean fluid in a major working component.

 

[AuSeeker]

I appreciate your response and info. Definitely makes sense! You may have just convinced me to do it after all haha. I love the idea of getting it changed, just hate the one of possibly causing “damage” to it, but I guess I’ll never know unless I try it. And there’s never anything wrong with getting clean fluid in a major working component.

Just a bit more FYI, just clean fluid usually will not dislodge sludge if present, what will dislodge sludge is doing a "power flush" of the transmission, many shops have a fluid flushing machine they use to flush transmissions, these machines use high pressure created by the machine to force new fluid into the transmission and pushing the old fluid out, I would advise to not let a shop do this type of flush, I would do the "fluid exchange" as described on the forum here using the cooling lines to let the transmission pump out a few quarts at a time, then add the same amount into the tranmission, and then repeat until clean fluid is being pumped out, thia will take around 12 to 14 quarts, by doing it this way you are only subjecting the transmission to normal operating pressure, or do several drain and fills about a month apart until you have replaced around 12 quarts.

 

[Whiskey & Wrenches]

I'm a big believer in synthetic fluids, I bought a 4Runner last year with 185K that was in great shape and didn't look like it had ever been off road. Shortly after, I put synthetic in all 3 differentials. A very easy job. It seemed like it ran smoother but I have no way of measuring that but my mileage did go up by 1 mpg which made me happy.

The transmission fluid on this vehicle was changed by the dealer at 100K, so I'm going to do another flush at 200 K. A tranny flush is cheap and I don't believe it will hurt my vehicle while replacing the 4WD transmission in my runner would be expensive and would definitely hurt my wallet, so I'll err on the side of caution.

I did break down and buy a case of Toyota fluid from the dealer (I think the guy made a mistake and I got a smoking deal, less than 5 bucks a quart out the door!) so Toyota fluid it is.

 

[Samm25]

Just a bit more FYI, just clean fluid usually will not dislodge sludge if present, what will dislodge sludge is doing a "power flush" of the transmission, many shops have a fluid flushing machine they use to flush transmissions, these machines use high pressure created by the machine to force new fluid into the transmission and pushing the old fluid out, I would advise to not let a shop do this type of flush, I would do the "fluid exchange" as described on the forum here using the cooling lines to let the transmission pump out a few quarts at a time, then add the same amount into the tranmission, and then repeat until clean fluid is being pumped out, thia will take around 12 to 14 quarts, by doing it this way you are only subjecting the transmission to normal operating pressure, or do several drain and fills about a month apart until you have replaced around 12 quarts.

Appreciate you! You’ve been a huge help to me. As well as everyone else. On with changing the differential fluid as well as transmission fluid!

 

[williamteichroeb]

couple things.....

Good on you for trying to do stuff yourself. I am a complete noob, youtube mechanic, but have learned so much since buying this 4runner and doing everything myself on it. It's incredibly rewarding, and easy if you're even a tiny bit mechanically inclined, have the right tools, and are ORGANIZED! go slowly, and do it right the first time.

Look into my build thread in the signature to see what I did, and pictures on the processes on the maintenance and upgrades....

change your front, transfer, and rear diffs at the same time. They are all easy, except the front uses a stupid 10mm hex bit.....Even being careful I stripped it the first time I changed my front diff...... before I started this project, I ordered brand new fill and drain plugs for everything as well as crush washers, and a breather plug. For about 30 dollars I'd recommend you do the same, then they'll all be new and you'll potentially save yourself some headache later

Lastly....I did a transmission flush on mine through toyota.....for about 100 dollars it will save you TONS OF HEADACHE. I took one look at the instructions and the mess some people go through, and said, yup, that's one job I'll pay a professional toyota dealership mechanic to do

Have fun,

Will

 

[rodsrunner]

Does the rear end fluid need any additives such as friction modifiers for the limited slip ?

 

[williamteichroeb]

Does the rear end fluid need any additives such as friction modifiers for the limited slip ?

No. 75-90 gear oil is what you need. Personally I used amsoil severe gear synthetic 75-90 gear oil in my front and rear diff as well as transfer case. It took approx....

1.5l for the front diff
1.5l for the xfer case
3.2l for the rear diff

 

[AuSeeker]

[MENTION=147280]williamteichroeb[/MENTION] , you say you had the dealer do the transmission fluid change and they only charged you $100, it sounds like they only did a "drain and fill" which only replaces 2 to 3 quarts, I assume this because of the cost of the fluid itself, just 1 quart of the WS fluid cost anywhere from $8 to $12 depending on where and how many you buy, so to do a complete fluid exchange using 12 quarts the cost of the fluid alone would be at a minimum of $96 to well over $100 and then you still have the labor cost, do you know exactly how much fluid they changed out?

 

[fihnguy]

Indeed, $100 is way too low. I was quoted 260 CAD a couple of weeks ago, which is close to 200 USD (they said about $260, whatever that means). The quote was obtained at the dealership over the phone and the person on the other end could not explain what exactly is included in the price.