Transfer case fluid? Best grade?

[Muzzle of Bees]

Multigrade gear oils
Viscosity of gear oils may be stabilized by polymeric additives (viscosity index improvers). Viscosity of such gear oils is specified at both high and low temperature. These oils are called multigrades and they are designated by two numbers and the letter “W” (SAE 75W-90, SAE 80W-90, SAE 85W-140 etc.). The first number of the designation specify the oil viscosity at cold temperature, the second number specifies the oil viscosity at high temperature.
For example: SAE 85W-140 oil has a low temperature viscosity similar to that of SAE 85W, but it has a high temperature viscosity similar to that of SAE 140.
Multigrade gear oils are used in a wide temperature range.

That’s why I specifically said in my post that the transmission fluid I purchased was not the manufacturer recommended oil, thicker. Hence the grinding at cold temps. I didn’t want to get into the differences between the multi vs. single weight oils.
Toyota transfer case fluid is their designed weight and works with their setup. I personally prefer the factory fluid. I’m not putting a multi weight fluid in my Toyota transfer case. I would rather not change the fluid then put in a multi weight that is recommended by someone at a help desk. I’m not buying anyone else’s used crap, so I’m not concerned if someone else has issues with their transfer case.
I was just at a local Toyota dealer near me and they are still replacing the 75 weight in the transfer case with the multi they put in both differential’s. Most people don’t keep their vehicle long enough to see problems so it’s likely difficult to get a good handle on the data.
I used to change oil viscosity from summer to winter too. That’s the old days and never had issues either, but then again, I didn’t keep my vehicle long enough to know if it had any adverse effects on the vehicle.

 

[CutthroatSlam]

That’s why I specifically said in my post that the transmission fluid I purchased was not the manufacturer recommended oil, thicker. Hence the grinding at cold temps. I didn’t want to get into the differences between the multi vs. single weight oils.
Toyota transfer case fluid is their designed weight and works with their setup. I personally prefer the factory fluid. I’m not putting a multi weight fluid in my Toyota transfer case. I would rather not change the fluid then put in a multi weight that is recommended by someone at a help desk. I’m not buying anyone else’s used crap, so I’m not concerned if someone else has issues with their transfer case.
I was just at a local Toyota dealer near me and they are still replacing the 75 weight in the transfer case with the multi they put in both differential’s. Most people don’t keep their vehicle long enough to see problems so it’s likely difficult to get a good handle on the data.
I used to change oil viscosity from summer to winter too. That’s the old days and never had issues either, but then again, I didn’t keep my vehicle long enough to know if it had any adverse effects on the vehicle.

316K miles on a 2014 that sees ambient temps ranging from 115 F in SoCal and the SW US deserts to -15 F in the winters of Montana and all I’ve used is 75w90 synthetic in the transfer case and differentials. Guess we haven’t kept our vehicle long enough.

 

[Grug556]

That’s why I specifically said in my post that the transmission fluid I purchased was not the manufacturer recommended oil, thicker. Hence the grinding at cold temps. I didn’t want to get into the differences between the multi vs. single weight oils.
Toyota transfer case fluid is their designed weight and works with their setup. I personally prefer the factory fluid. I’m not putting a multi weight fluid in my Toyota transfer case. I would rather not change the fluid then put in a multi weight that is recommended by someone at a help desk. I’m not buying anyone else’s used crap, so I’m not concerned if someone else has issues with their transfer case.
I was just at a local Toyota dealer near me and they are still replacing the 75 weight in the transfer case with the multi they put in both differential’s. Most people don’t keep their vehicle long enough to see problems so it’s likely difficult to get a good handle on the data.
I used to change oil viscosity from summer to winter too. That’s the old days and never had issues either, but then again, I didn’t keep my vehicle long enough to know if it had any adverse effects on the vehicle.

The big problem is that you cant get 75w or 75w85 at any Toyota dealers ive ever been to. Most seem to use low grade mineral 75w90. Funny today I went to the dealer for some gaskets, asked about the oil. They cant get it they say..yet they happily gave me a print out from Toyota Canada saying use 75w for transfer case of void your warranty. Thats some funny shit... use what we wont and cant sell you...

I got transfer case draining now. Odd the bolts were barely finger tight.

 

[kjbenner]

I just did all my fluids today, and used Redline MT-LV GL-4 in the transfer case. I've since driven about four miles and haven't died yet.

 

[02SE]

I just did all my fluids today, and used Redline MT-LV GL-4 in the transfer case. I've since driven about four miles and haven't died yet.

The Aisin VF2A transfer case in your Trail, was speced for 75w90 for years, before Toyota decided to try and eeek out a fraction of an MPG improvement, with the 75w spec oil.

The oil you put in is fine. A 75w90 would be fine too.

 

[Grug556]

Guys anybody have the torque specs for the transfer case fill and drain bolt? I cant find them anywhere. I think the specs are low, but need to confirm.

I am seeing 27lbs torque on transfer case fill and drain bolt? This sound right?

 

[jdc62]

Here's a link to maintenance information for the 5th gen 4Runner. It includes torque specs. Both are 27 lb-ft.

DIY maintenance quick reference

 

[Grug556]

Thanks!!! Appreciate it. Ive found tons of diagrams online, must have their toque specs removed..ugh!

:becky:

 

[jbtvt]

Hey any links on this? I did a quick search and found several saying their Redline made their diffs seems smoother? Only thing I saw was one person saying it made their motor louder on the lifters etc, using 10w30 redline, which is a bit thick.

Here's a couple just generally talking about thinner synthetic causing a whine

Just a moment...

Just a moment...

And redline specifically here
Rear diff whine after fluids swap - PeachParts Mercedes-Benz Forum

 

[02SE]

Here's a couple just generally talking about thinner synthetic causing a whine

Just a moment...

Just a moment...

And redline specifically here
Rear diff whine after fluids swap - PeachParts Mercedes-Benz Forum

Those links don't indicate that 'thinner synthetics cause a whine'.

The first link sounds like maintenance neglect, and a worn differential.

The second the Explorer diffs from that era were known to have issues.

The third is a high-mile, worn, neglected example.

Lack of maintenance and/or a poor design are the big issues in those examples.

Draining out neglected gear oil which has become filled with metal debris, and thickened due to neglect, and then replacing with clean gear oil makes the existing wear more audible, the problem is the excessive wear, not the new gear oil. The gears and bearings are on borrowed time either way.

 

[jbtvt]

Those links don't indicate that 'thinner synthetics cause a whine'.

The first link sounds like maintenance neglect, and a worn differential.

The second the Explorer diffs from that era were known to have issues.

The third is a high-mile, worn, neglected example.

Lack of maintenance and/or a poor design are the big issues in those examples.

Draining out neglected gear oil which has become filled with metal debris, and thickened due to neglect, and then replacing with clean gear oil makes the existing wear more audible, the problem is the excessive wear, not the new gear oil. The gears and bearings are on borrowed time either way.

The first example had 80k miles, that's sooner than 99.9% of diffs on the road will get a service and is in no way neglected. I previously owned 3 Explorers and never had a diff problem, and never heard of it being an issue with anyone else I've known who had them. Transmissions are another story. Regardless of whether you've heard differently, every link is an example of someone replacing thicker dino with thinner synthetic and a whine appearing after, colloquially speaking, "causing". I've changed plenty of high mile neglected diff fluid before with 80w90 dino and never gotten a whine.

Here's another, went away when he switched back to dino
Just a moment...

And another one about brand new vehicles with a common whine that often goes away when thicker oil is swapped in
Rear differential whine | Page 2 | Dodge Challenger Forum

It's very possible the whine is harmless, I recall someone else with the issue speculating about that on I think Ih8mud.com when researching it the first time, and I don't plan on changing mine again soon unless it gets worse. Certainly the straight cut gears in my 3500 Chevy trans make a ton of noise and always have. I also don't own a 5th gen so maybe the gear pattern can handle it better if they're specing straight 75w. This was my experience and that of quite a few others, weight it how you will.

 

[CutthroatSlam]

Those links don't indicate that 'thinner synthetics cause a whine'.

The first link sounds like maintenance neglect, and a worn differential.

The second the Explorer diffs from that era were known to have issues.

The third is a high-mile, worn, neglected example.

Lack of maintenance and/or a poor design are the big issues in those examples.

Draining out neglected gear oil which has become filled with metal debris, and thickened due to neglect, and then replacing with clean gear oil makes the existing wear more audible, the problem is the excessive wear, not the new gear oil. The gears and bearings are on borrowed time either way.

Thank you for this post. Anecdotal internet posts identifying a correlated observation do not represent a causal relationship. Uninformed, inexperienced grasp at correlation because they don’t know enough to ID causal.

 

[jbtvt]

Thank you for this post. Anecdotal internet posts identifying a correlated observation do not represent a causal relationship. Uninformed, inexperienced grasp at correlation because they don’t know enough to ID causal.

"Uninformed, inexperienced" yea, ok bud.

I'm the first one to call out selection or sampling bias when it comes to things like transmission fluid changes (not) leading to failures, this is not that. Thinner oil can lead to more gear noise. More viscous oil will generally lead to less gear noise. That does not necessarily mean that a higher viscosity is better, even if it reduces noise, although personally I'd rather have a slightly more viscous oil and no noise the the other option.

If you're unaware of any of this, then you've got some "experiencing" to do. You can debate the cause, or whether the noise leads to damage, but get off your high horse first.

 

[baldrik78]

I've used Redline MT-LV in the transfer case and Redline 75w90 in the diffs on the last 2 fluid changes. It's all been fine for 50k miles.

 

[CutthroatSlam]

"Uninformed, inexperienced" yea, ok bud.

I'm the first one to call out selection or sampling bias when it comes to things like transmission fluid changes (not) leading to failures, this is not that. Thinner oil can lead to more gear noise. More viscous oil will generally lead to less gear noise. That does not necessarily mean that a higher viscosity is better, even if it reduces noise, although personally I'd rather have a slightly more viscous oil and no noise the the other option.

If you're unaware of any of this, then you've got some "experiencing" to do. You can debate the cause, or whether the noise leads to damage, but get off your high horse first.

If the viscosity rating says 75w90, then there is no difference in the viscosity between mineral and synthetic oil. What's your basis for claiming "thinner oil?"

 

[Bmnorm2]

Maintenance schedule calls for inspecting diff oil at 30k and replacing if needed or if “heavy duty” use . Waiting till 90k is abuse.

Generally, you want to replace diff oil after break in to get all of the metal debris from gear meshing out and clear the magnet. After that the oil can last a very long interval if not subjected to high temp/heavy use case or contaminated from fording or bad vent.

 

[CutthroatSlam]

Maintenance schedule calls for inspecting diff oil at 30k and replacing if needed or if “heavy duty” use . Waiting till 90k is abuse.

Generally, you want to replace diff oil after break in to get all of the metal debris from gear meshing out and clear the magnet. After that the oil can last a very long interval if not subjected to high temp/heavy use case or contaminated from fording or bad vent.

This ^^^ is good advice. I’m changing at approximately 50K intervals with 75w90 synthetic. This last change at over 300K miles had minor sludge on the drain plug magnet and the oil was clear and same color as new oil.

 

[Mike Beyers]

75/140 Valvoline synthetic in the diffs. 75/90 Valvoline synthetic in the Tcase. Both done at 100k. Both will get changed again at 200k. I'll be the first to let you all know if anything changes, but I don't think it will.