Are there any risks to doing this? The car has well over 200,000 miles and I was considering doing some proactive maintenance. Is there any reason I shouldn't change the gear oil?

 

Tell me they have been changed before...??

Take it easy on him fellas...

Fink

 

while you're under there change your muffler bearings as well.
http://kalecoauto.com/index.php?main...products_id=10

and your blinker fluid
http://kalecoauto.com/index.php?main...&products_id=6

 

Fink

 

Wow, this is the maturity level you expect of your forum? I suppose it's good for your ego to lurk the newbie forum?

 

We're just razzing you - figured we'd break the ice before the other members start posting.

We're mods so we have to "lurk" everywhere!

Seriously though, please tell me those fluids have been changed before?

Fink

 

This question would have probably been a better one to ask your buddies or your local autozone guy. When you throw a question like this out for 57,000 members to see expect to get razzed a little. And Fink is right...were everywhere around here "lurking" I moved your thread here. Consider yourself lucky because normally threads like these get immediately deleted.

No there's no reason to NOT change your fluids especially if you have no clue when they were changed last. While your at it spend a few extra bucks and put some good synthetic in there such as Royal Purple, Amsoil, or Redline. I run Royal Purple in all my vehicles only because I can get it locally. Your owners manual will tell you how much and what weight each component holds and there are a few write ups in the tech section of the forum that tell you how to do it.

Oh ya and please dont' call your 4-Runner a "Car" ever ever again.

 

if someone had been doing proper maintance on the truck the diff/TC fluilds would have been changed every 15K-30K..

you can download the Factory Service Manual using the hyperlink in my sig
it will have the recommended maint. schedule etc.

 

The most important thing to figure out is whether this stuff has been done before (surely it has) and when the last time it was done.

Fink

 

OK. It's all good.

The 4runner has been my wife's car since I met her. She bought it at 136k miles and it now has around 220k miles on it (hard to tell with faulty VSS and quirky odometer). All I know is what has been done to it since she got it and not before.

To be honest, it's kinda weird. I have done most of my own repairs and tune-ups over the last 20 years or so and have never once done, or heard of anyone doing, a fluid change in differentials. It's just not something people do around here for whatever reason. That's why I thought it to be a valid question as I wanted to take care of my wife's car with our twins on the way

So... I can't tell you it's been done before. That's why I'm doing it now, along with the myriad of other repairs that it needs.

So thank you all so much for the harsh lesson in gear oil changing!

 

Changing your diff fluids isn't a regional thing - everybody around the world does it. You may seriously benefit from reading the owner's manual - there's probably a few other things in there you may not have known about like greasing your driveshaft, changing your coolant, tranny fluid, the other diff, etc... oh and of course the muffler bearings! That website is awesome Tofer.

 

I'm not sold on the Royal Purple-Redline-Amsoil spiel. I bought some Mobile 1 for eight bucks a quart after finding out the Royal Purple was a lot more. What's the big deal if you change it every 20k?

 

Mobil 1 gear oil is synth too isn't it? I personally don't believe it matters one bit if you change it every 20-30K, but a lot of people go way longer than that and Amsoil for instance is a longer interval than most (I could be wrong, but I believe it's 60K for their gear lube).

You don't need to do it as often which in the long run can save you $$. I still would personally rather do Mobil 1 every 30K than Amsoil every 60K, mostly because I think it's better protection to run a fluid that's say 90% as good, but only for 1/2 as long. After 50K, I'm sure the Amsoil is more broken down than 20K old Mobil 1 would be.

 

Yep, it's full synth. Just 75 W90. Let's just figure out the cost:
Tranny = 2.5 quarts
t-case = 1 quart
rear diff = 3 quarts
front diff = 1.5 quarts

Total = 8 quarts at $8 apiece = $64

Except for the front diff, the oil is easy to change. I drive at most 10k a year, so that means I should do a change every two to three years. That's $32 a year if I change it out every 20k. That's nothing! And, personally, I wouldn't change out the front diff or t-case oil but every 50 - 60k because it just doesn't get used as often. Really, the tranny and rear diff are all you need to worry about every 20-30k. That's only 6 quarts = $48 = $24 a year!

It's so cheap I might as well do it every 10k!

 

Short answer is, it's 100% necessary to change the differential fluids.
Just like motor oil, there is degradation whether the vehicle is moving or not - the more you use it, the most frequently you need to change the fluid.

I would change that ASAP.
If you wanted to be sure you got it cleaned out - I would run it for maybe 1,000-2,000 miles and then change it again.
I always go way above and beyond when it comes to regular maintenance and it seems to pay off on each rig I own.

As the others have said, and I mean this is in a completely non-condescending way, definitely read the owners manual.
Maybe keep it next to the toilet for the next few days, get some good quality reading in.

There is also a ton of info on here and all over the web about preventative maintenance - do a few searches on here about it and you'll have even more reading to do.

Changing fluids can never really hurt anything, as long as it is done right and done on time.



Fink

 

Synthetic oil has far less drag than regular gear oil. I picked up 2mpg and had a noticeable increase in power after switching to synthetic in my drivetrain. When your only getting 15-16mpg that's huge. If you change your oil every 20K your the vast minority out there. I'd venture to guess there are plenty of vehicles out there with well over 100K that have never been changed or checked. In my Tundra manual it doesn't have you touch it until 60K.

 

I'd agree that synth is the way to go. What I don't believe is all the hype that one oil is so much better than the other. It's easy to find Mobile 1, but you have to jump through hoops to get Amsoil. Royal Purple is super expensive, and I haven't been able to locate Redline. All I'm saying is that the OP should go to NAPA immediately and pick up some decent oil to stick in his drivetrain.