swampy_swimmer
New member
So, 80W90 3 qts.
Never changed since I got it, probably 40K miles.
What do you think: Synthetic or Non?
Thanks.
Never changed since I got it, probably 40K miles.
What do you think: Synthetic or Non?
Thanks.
Changing Rear Diff Fluid. Synth or Regular?
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mtbtim
Elite Member
#1, it should have been changed much sooner. Every 30,000 miles at a minimum under normal driving conditions. If you tow or are regularly loaded down with lots of weight, it's advisable to change it every 15,000 miles. I just changed mine at a 30,000 mile interval and it looked pretty darn dirty. I'm going to switch to a 15,000 mile interval due to the way I use my rig and based off how dirty the gear oil was waiting 30,000 miles.
With that said, choosing between synthetic and conventional is all personal preference. But, being that synthetic is a little thinner than conventional, you might end up getting some leaking through your axle seals if they are worn and on there way to be needing to be replaced.
If it were me, I'd use a conventional 80w-90 because it's a safer bet that you won't have any issues after the fluid renewal.
With that said, choosing between synthetic and conventional is all personal preference. But, being that synthetic is a little thinner than conventional, you might end up getting some leaking through your axle seals if they are worn and on there way to be needing to be replaced.
If it were me, I'd use a conventional 80w-90 because it's a safer bet that you won't have any issues after the fluid renewal.
Strange that Toyota spec'd 80W90 in the rear diff but 75W90 everywhere else. Maybe to save cost. It doesn't really matter which you go with, but personally I use 75W90 due to the -45C winters here in Canada. I also get a nice corporate discount when buying whole 5 gallon pails of gear oil so I just stick with one oil.
The only advantage I can think of for 80W90 is cost and maybe slightly higher shear stability, but that shouldnt matter if you're changing the fluid out regularly.
The only advantage I can think of for 80W90 is cost and maybe slightly higher shear stability, but that shouldnt matter if you're changing the fluid out regularly.
PWD4R
New member
I think it depends on the vehicle honestly. My last vehicle recommended for 40k intervals and I did 50k and it was perfect. Looked brand new; only wiped off the magnet.
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swampy_swimmer
New member
I read somewhere about RP and how happy the owner was with it. But he did a lot of towing. I don't.
If I go with conventional, does brand matter? or I can just buy cheap Walmart brand like Supertech. Or better go with something like Lucas?
If I go with conventional, does brand matter? or I can just buy cheap Walmart brand like Supertech. Or better go with something like Lucas?
You're right. I'm doing 50,000 km intervals on my driveline fluids and they look almost new when I drain them. This is with mild offroading too. Most of the break-in wear happens when the truck is brand new off the lot. With 300,000 kms+ on the clock things have been pretty steady.
jgue467
Senior Member
I went with wally world's full synth 75-140 about 100k ago, changed twice since, no leaks before or after, great stuff at a great price. Luck! :cowboy:
Super Tech 75W-140 Synthetic Gear Oil, 1 Quart - Walmart.com
Super Tech 75W-140 Synthetic Gear Oil, 1 Quart - Walmart.com
I was going to ask about the super tech stuff. Its super cheap so it always has me a little leery to try it out.
mtbtim
Elite Member
That's interesting you say your gear oil looks almost new after 50,000 km (30,000 miles) and [MENTION=141906]PWD4R[/MENTION] says his looks perfect even after 50,000 miles. My rear differential fluid after 30,000 miles was pretty dark, so that got me thinking maybe I should change it more frequently. I'm not really towing a lot, but I do quite a bit of mountain driving loaded down with gear.
The whole k or km is a little confusing on this thread. When I hear somebody say 40k, I think 40,000 miles. But then others are saying km, which is obviously kilometers. Anyway, I think I got it figured out.
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Konkordmusk
New member
There are no wearable materials inside an axle tube. The fluid being dark can only be a result of dirt or anything allowed inside the breather, if anything. At any rate, new fluid will do a decent job of cleaning the inside and suspend any loose particles by design. I do 50k intervals as well, but I do keep an eye on my fluid, since I wheel so hard, tow pretty often and I recently regeared. Not yet have I determined I needed to change the fluid prior to 50k based on the condition of the fluid. Discoloration of any oil is absolutely not a reliable symptom.
PWD4R
New member
Mine was miles. I owned the vehicle starting at 27k so I doubt the previous people off roaded. I had mine in 4 wheel drive every week and both diffs were bright pink and the xfer was perfect. Like I said just wiped the magnet and that was all. Granted the magnet was built up a solid quarter inch so maybe it was still strong enough not to have any shavings floating around but after seeing that I didn't plan on changing it until 100k.
Editing for clarification: I still changed it at the 50 though. I didn't reuse it lol
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Editing for clarification: I still changed it at the 50 though. I didn't reuse it lol
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mtbtim
Elite Member
Well, something is happening with the gear oil to turn it a darker color and I'm having a hard time believing it can be attributed to dirt finding it's way into the breather. That breather hole is small and covered with that cap so I'm thinking very little dirt could find it's way into there, and if it did, it's not going to be enough to change the color of the gear oil. If it's true that much dirt can enter the diff breather, I'm definitely going to do the breather mod and run it up to the gas tank fill tube. I drive dirt roads quite a bit but I haven't had the need to cross any deep creeks so I haven't bothered with that mod yet.
I agree there's nothing really wearable in the axle tube other than maybe the axle seals and bearings, BUT, there's definitely wearable parts in the differential. The drain plug is magnetized and I find a small amount of metal debris attached to it every time I change the gear oil so there's definite wear happening.
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mtbtim
Elite Member
I did, sort of. Don't know if all the years are the same but my owner's manual called for 80W-90. There's can't be that much of a difference between 80W-90 and 75W-90 so I understand why some are just using 75W-90 in everything since the transfer case and front diff call for 75W-90.
My manual actually said to use straight 90W for temps above 0 degrees F and use 80W-90 for temps below 0 degrees F. I couldn't find straight 90W, so I just got some 80W-90 and called it good.
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Mozambique
New member
Hi Guys,
I hope to take delivery of my new to me Surf and would like to do a full fluid change out.
There are only two products available to me immediately.
Castrol and Fuchs.
I eventually will go fully synthetic when I can find the right stuff probably out of country, but for now which brand would you guys suggest/recommend please.
Thanks,
Moz.
I hope to take delivery of my new to me Surf and would like to do a full fluid change out.
There are only two products available to me immediately.
Castrol and Fuchs.
I eventually will go fully synthetic when I can find the right stuff probably out of country, but for now which brand would you guys suggest/recommend please.
Thanks,
Moz.
NoVAphotog
New member
I use Mobil 1 75W90 for both front and rear diff as well as transfer case with good results, no leakage, 233K miles.
Just used the same on mine all around. No issues. Old fluid looked ****ing disgusting. Glad I did it when I did...