Diff Fluid Question
#1
Diff Fluid Question
For the rear differential, it says to use a particular type of gear oil for above 0 degrees F and another one for below 0 degrees F.
If our winter consists of both temperatures, which type/weight of gear oil should I be putting in?
Al
If our winter consists of both temperatures, which type/weight of gear oil should I be putting in?
Al
#3
I would use the above 0 dergee weight, but I would use synthetic as it flows better at sub zero (as in it does flow).
You need the higher temp stuff to lube adequately at the upper temps, and the lower temp stuff so it isnt like peanut butter when cold. Synthetics do both, but at a higher cost (but cheaper than doing 2 changes a year to keep the "right" oil in there)
I use Valvoline 75W-90 synthetic in all my gearboxes and diffs.
That is a Landcruiser, Toy 4x4, Heep Cherokee (diffs only, sythetic ATF in TC), and Subaru. I like its extreme anti wear properties
My local NAPA store gets $9 qt for it (US $)
You need the higher temp stuff to lube adequately at the upper temps, and the lower temp stuff so it isnt like peanut butter when cold. Synthetics do both, but at a higher cost (but cheaper than doing 2 changes a year to keep the "right" oil in there)
I use Valvoline 75W-90 synthetic in all my gearboxes and diffs.
That is a Landcruiser, Toy 4x4, Heep Cherokee (diffs only, sythetic ATF in TC), and Subaru. I like its extreme anti wear properties
My local NAPA store gets $9 qt for it (US $)
#4
More on my diff fluid issue...
Thx for the reply YodaDood. 
New news on this. After much frustration (actually not 'much frustration'...let's say 'some frustration'), I'm going with 75W-90 Amsoil synthetic in both front & rear diff & the transfer case. Let me explain...
I called PartSource & they said they only have 75W-90. I call Toyota and speak with their service guy. He says it should be 85W-90 in the rear diff. I call PartSource back, nope, they don't have it. I call Toyota back and the other service person I spoke to says 75W-90 in the front/rear and transfer case and that the other guy was on crack.
I talk to the PartSource guys again and they were as surprised as I was. We wondered to ourselves "Why would I want a more viscous gear oil in my rear diff? Plus, the 80W-90 (recommended by some) is dino oil, not syn oil so it may not entirely count for synthetic."
All the text books we found said 75W-90 goes in both diffs and the transfer case for my 97 4Runner.
Here's our conclusion after reading the specs on the gear oil:
-75W-90 is obviously more flowing than 80W-90 or 85W-90
-at a higher temperature, the 80W/85W is more like molasses than the 75W which is good for protection (to a point) but bad for fuel economy
-the gear oil being more fluid/flowing is fine, especially as it's below 0 degrees F right now
-the pouring temp of 75W is lower than 80W so it won't freeze up on me for sure
-with a less viscous rear diff oil, there shouldn't be as much pressure in there as there would be with the 80W or 85W and hopefully that will help prevent me from blowing another rear axle seal
-The book says so.
Anyhow, those were our thoughts on the gear oil confusion.
I bought all 6 gaskets (thx jalaber for the part #'s from your site) and am good to go. I'm getting it all changed tomorrow. If anyone has any last second "GAWD NO! NO! NO! DON'T DO IT!" comments, please pipe in soon.
Al

New news on this. After much frustration (actually not 'much frustration'...let's say 'some frustration'), I'm going with 75W-90 Amsoil synthetic in both front & rear diff & the transfer case. Let me explain...
I called PartSource & they said they only have 75W-90. I call Toyota and speak with their service guy. He says it should be 85W-90 in the rear diff. I call PartSource back, nope, they don't have it. I call Toyota back and the other service person I spoke to says 75W-90 in the front/rear and transfer case and that the other guy was on crack.
I talk to the PartSource guys again and they were as surprised as I was. We wondered to ourselves "Why would I want a more viscous gear oil in my rear diff? Plus, the 80W-90 (recommended by some) is dino oil, not syn oil so it may not entirely count for synthetic."
All the text books we found said 75W-90 goes in both diffs and the transfer case for my 97 4Runner.
Here's our conclusion after reading the specs on the gear oil:
-75W-90 is obviously more flowing than 80W-90 or 85W-90
-at a higher temperature, the 80W/85W is more like molasses than the 75W which is good for protection (to a point) but bad for fuel economy
-the gear oil being more fluid/flowing is fine, especially as it's below 0 degrees F right now
-the pouring temp of 75W is lower than 80W so it won't freeze up on me for sure
-with a less viscous rear diff oil, there shouldn't be as much pressure in there as there would be with the 80W or 85W and hopefully that will help prevent me from blowing another rear axle seal
-The book says so.
Anyhow, those were our thoughts on the gear oil confusion.
I bought all 6 gaskets (thx jalaber for the part #'s from your site) and am good to go. I'm getting it all changed tomorrow. If anyone has any last second "GAWD NO! NO! NO! DON'T DO IT!" comments, please pipe in soon.

Al
#5
You might want to get yourself a cheater bar for the front diff fill plug. I had a time with mine when trying to remove it.
#7
Make sure you drive it some distance to warm up the diffs before draining. Below zero the dino won't want to come out. Might be a good idea to loosen both drains and filler plugs to make sure you don't have one bound up first. Snug them before the warmup drive.
Just curious, how much is the Amsoil 75W-90??
Just curious, how much is the Amsoil 75W-90??
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#8
I agree. After the warm-up, make sure that the fill plugs can be opened BEFORE you drain all your fluid. And are you doing this outside? In this weather? Oooo, your a stronger man than me. I'm coming up on the need to flush out my coolant but I think I'll wait, oh, three of four more months!
Good luck.
Good luck.
#9
I'm going to drop it off at the garage by my work, on my way to work. It's -6 degrees F out. I'm not freezing off my calzones to change the fluids.
I'd like to do it myself but I want it done now, and it's too cold for me, especially w/o a heated garage.
Thx for the info about warming up the dino oil first though, I will make sure that happens.
The Amsoil 75W-90 is pricy. It cost me almost $9 USD a quart, and I bought 6 of 'em.
To those of you who changed them or have seen the gaskets, did you notice the front diff fill gasket is monstrous in comparison to the other 5, or is that just a wild optical illusion?
EDIT: "front diff fill" should read "front diff drain"
I'd like to do it myself but I want it done now, and it's too cold for me, especially w/o a heated garage.
Thx for the info about warming up the dino oil first though, I will make sure that happens.
The Amsoil 75W-90 is pricy. It cost me almost $9 USD a quart, and I bought 6 of 'em.
To those of you who changed them or have seen the gaskets, did you notice the front diff fill gasket is monstrous in comparison to the other 5, or is that just a wild optical illusion?

EDIT: "front diff fill" should read "front diff drain"
Last edited by HBoss; Jan 16, 2003 at 07:09 AM.
#10
No, you're absoultely right. And the friggin parts dept by me was like "They'er all the same size" while staring a a schematic of the diff on his computer. I so look forward to seeing this guy again.
#11
Well, it's all done. Next time I do it myself in warm weather though. An hour of labor to change the diff & transfer case fluids, ouch. Not to mention it cost me about the same for the gear oil. I'm glad this doesn't have to be done that often.
On the bad side though, they told me I had some shavings come out on the rear diff plug/bolt. Not a lot of shavings, but some, which isn't good. Hopefully synthetic will help a bit.
Does anyone else here think I should be concerned? I'm sure the diff in there will still last me quite some time yet, but what do you guys think?
Al
On the bad side though, they told me I had some shavings come out on the rear diff plug/bolt. Not a lot of shavings, but some, which isn't good. Hopefully synthetic will help a bit.
Does anyone else here think I should be concerned? I'm sure the diff in there will still last me quite some time yet, but what do you guys think?
Al
#13
Originally posted by Yoda
Normal to see a little bit of stuff on the magnet. Hopefully no big chunks.
Normal to see a little bit of stuff on the magnet. Hopefully no big chunks.
#15
1 gasket each for:
-front differential fill plug
-front differential drain plug
-transfer case fill plug
-transfer case drain plug
-rear differential fill plug
-rear differential drain plug
Not sure if it's the same for the 2nd gens but if they include all of the above, my guess is yes. You can use the old gaskets but it's highly recommended you buy new ones each time, especially as all 6 is only about $5.
Al
-front differential fill plug
-front differential drain plug
-transfer case fill plug
-transfer case drain plug
-rear differential fill plug
-rear differential drain plug
Not sure if it's the same for the 2nd gens but if they include all of the above, my guess is yes. You can use the old gaskets but it's highly recommended you buy new ones each time, especially as all 6 is only about $5.
Al
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