I want to change all fluids.. but how many are there?

[Carbon]

Originally Posted by friendly_jacek

2. the SAE grade specification is based on 100C (212F) temp viscosity. The diff are not going to be that hot, I measured 100-120F external temp in RAV4 IIRC. Thus, 75W90 will be much thinner compared to 80W90 and especially 90 during the working temps. While this could be potentially beneficial in very cold, but not necessarily in hot climate.

Thus, 75W90 is not comparable to 90 in the working temp conditions.

My read is the engineers specified 90 for driving above 0F. Keep in mind that is equivalent to SAE 110 in the revised gear SAE rating. That was "lost in translation" as 80W90 for everyone anytime. Now, even thinner 75W90 are used by owners. This is going away from the original specification.

Interesting point.

Regarding your "revised" comment, is that what is being referred to in Gear oil - Wikipedia, the free encyclopedia where it says

API viscosity ratings for gear oils are not directly comparable with those for motor oil, and they are thinner than the figures suggest. For example, many modern gearboxes use a 75W90 gear oil, which is actually of equivalent viscosity to a 10W40 motor oil.

Are you saying that the revision occured after the rav4.3 specifications, or are you saying that 80W-90 is not nearly as thick as the numbers would seem to imply. Surely if you go buy the 80W-90 or 90 today, it matches what the engineers intended to specify. Or no?

Using higher viscosity would offer some extra protection and quieting with a small effect on fuel economy.

[friendly_jacek]

Originally Posted by Carbon

Are you saying that the revision occured after the rav4.3 specifications, or are you saying that 80W-90 is not nearly as thick as the numbers would seem to imply. Surely if you go buy the 80W-90 or 90 today, it matches what the engineers intended to specify. Or no?

The revision happened in 2005, after the 4.3 RAV4 development and testing:
http://www.penriteoil.com.au/tech_pd...IFICATIONS.pdf

SAE 90 used to be 13.5-24 cSt @100C. There was no 110 grade and the next one was 140. Dino SAE 90 used to start on the thick side to allow for shear down in service. That viscosity, typically over 20 cSt, is now designated as SAE 110. Thus, the post 2005 SAE 90 oils are significantly thinner than they used to be.

[pepepeter]

folks, i have in my possession valvoline durablend synthetic 80w-90 gear oil for both transfer case and rear differential (Valvoline/1 qt. 80W-90 Durablend synthetic gear oil (280) | Gear Oil | AutoZone.com_).

I spoke with the parts department of earnhardt toyota (in AZ of highway 60, mesa, az) and they mentioned in ALL rav4s they put 75w-90 with a limited slip additive (???) for both transfer case and rear differential with no complaints regarding issues with this weight during the summer (>115F). Almost seemed to imply its okay with warranty if I use 75w-90... yeah right!!!!

[pepepeter]

Update for those interested...

I drained, flushed, and filled both the transfer case and rear differential with the Valvoline 80W-90 durablend synthetic gear oil. It went smooth, but getting off the filler and drain plugs was a challenge. In both case the old gears were nasty looking and filledwith black shavings that seemed more like a sludge than metallic particles. See pics.

During the rav4 around for 3 days and the new gears oils, it seems smoother, but there is a slight squeek or shimming sound that is barely audible (sounds similar to a hamster wheel). Anyone know why this sound is now present? It occurs when accelerating and last for no more than 1 second, but obviously was not there withthe old gear oil. Is this a consequence of using a synthetic blend?

[ARK]

pepepeter, you exchanged dirty hypoid with synthetic clean hypoid and thus have removed grindings in the form of small metal particles. These particles grind up to even smaller particles and with time and use and blending with hypoid oils become a grease of sorts and lubricate the crown/pinion and bearing surfaces.

The removal of the grease type grindings may have left a space where frictional parts could cause this minor squeal. You will have to drive more and let the new hypoid oils get into all the areas.

After a month it should be quiet but I suggest yet another exchange as any particles left in suspension can now be drained then replace the hypoid every 2 years. The use of synthetics in crown/pinion are not required because standard hypoid does a great job but remove it every 2 years.

Leaving oils of any kind in service for too long can create a problem with bearings, rubbing surfaces as cooling is diminished, lubrication suffers from crap build up in the oils and O2 oxygenates the lube plus dirt and rust from ferrous and non ferrous as copper, brass get into the mix and add particles to impede lubrication.

Just look at the mess that came out of your gear box and that box is enclosed. Be very watchful of the used oils coming out because they indicate wear.

The Rav4 uses a front differential mated with the transmission and the front diff is lubricated with ATF. The front diff is 100% a work horse in the drive line and crown/pinion gears present a great shear force. ATF compared to hypoid in this extreme condition can be a disaster. The saving grace is the ATF is being pumped around the front end and the differential. The oil ATF is a WS, synthetic but in my opinion should be checked , tested and replaced sooner than what is expressed in the manual

Differentials and lubrication.
I own and operate a 33 year old Goldwing. Rear end takes 80W90 hypoid. Put in 90W140, because the only available grade. Within a week the oil was migrating up and out the breather. Dumped it and ordered the correct grade. Be very careful with oil grades to match your ambients and machine temperatures

[pepepeter]

Originally Posted by ARK

pepepeter, you exchanged dirty hypoid with synthetic clean hypoid and thus have removed grindings in the form of small metal particles. These particles grind up to even smaller particles and with time and use and blending with hypoid oils become a grease of sorts and lubricate the crown/pinion and bearing surfaces.

The removal of the grease type grindings may have left a space where frictional parts could cause this minor squeal. You will have to drive more and let the new hypoid oils get into all the areas.

After a month it should be quiet but I suggest yet another exchange as any particles left in suspension can now be drained then replace the hypoid every 2 years. The use of synthetics in crown/pinion are not required because standard hypoid does a great job but remove it every 2 years.

Leaving oils of any kind in service for too long can create a problem with bearings, rubbing surfaces as cooling is diminished, lubrication suffers from crap build up in the oils and O2 oxygenates the lube plus dirt and rust from ferrous and non ferrous as copper, brass get into the mix and add particles to impede lubrication.

Just look at the mess that came out of your gear box and that box is enclosed. Be very watchful of the used oils coming out because they indicate wear.

The Rav4 uses a front differential mated with the transmission and the front diff is lubricated with ATF. The front diff is 100% a work horse in the drive line and crown/pinion gears present a great shear force. ATF compared to hypoid in this extreme condition can be a disaster. The saving grace is the ATF is being pumped around the front end and the differential. The oil ATF is a WS, synthetic but in my opinion should be checked , tested and replaced sooner than what is expressed in the manual

Differentials and lubrication.
I own and operate a 33 year old Goldwing. Rear end takes 80W90 hypoid. Put in 90W140, because the only available grade. Within a week the oil was migrating up and out the breather. Dumped it and ordered the correct grade. Be very careful with oil grades to match your ambients and machine temperatures

Just gotta say wow; very informative and thanks for taking the time to reply. Im glad to hear the minor squeal is not a major issue just a side effect, especially since another member placed doubt i my head since they claimed a school whine in there rear diff lead to failure. I guess my question is why didnt i hear that when it was brand new? Unfortunately i wont beable to change it anytime soon im moving to oregon from arizona for 6 months. I do believe the valvoline is a synthetic blend, but yes not conventional gear oil.

[RTexasF]

Originally Posted by 4x4 rav

You can change most fluids. however it is not advisable to change all the brake fluid in all the lines. you just need to top the reservoir if needed.

This is 100% wrong. Honda requires it be done every three years where Toyota fails to mention it at all. Just because they failed to mention it does not mean the service should not be done. As previously mentioned the fluid becomes contaminated with moisture over time and can't do its job properly. I'll be having both of ours done this month since they are now five model years old. Read up on it and educate yourself as to why this is necessary.

Pepeter - glad you got the lubes handled. This is another case where Toyota gives poor information but that doesn't mean the service should not be performed.

[IZZY]

I know what the books say. Lets just say I've gotten away with never changing brake fluid for 35+ years in any of my cars and I keep them 15 years or more. Never had anything more than a squeak. I've got a 17 year old Grand Caravan in my driveway now. Brakes are fine. I just never open the lines when changing pads. Never had to change a caliper or brake line. This story may be different if I lived in the southeast.

[friendly_jacek]

Originally Posted by pepepeter

I drained, flushed, and filled both the transfer case and rear differential with the Valvoline 80W-90 durablend synthetic gear oil. It went smooth, but getting off the filler and drain plugs was a challenge. In both case the old gears were nasty looking and filledwith black shavings that seemed more like a sludge than metallic particles. See pics.

Is the rear diff fluid on the left and transfer on the right? I remember rear diff fluid worse than transfer at 22,000 miles, but not so much as yours. If so, rear diff works very hard and stresses the fluid a lot. This is a remainder for anyone who never did one of those to do it before its too late.

The problem with gear oils is like ATF, if you wait too long and gears adjust to thick goop, changing to new fresh fluids, especially low viscosity synthetics, causes new noises and sometimes failures. I had that in my Subaru and learned a lesson.

BTW, how much metal did you see on the magnetic drain plugs? That is graded in 3-tier system: fuzz, whiskers or Christmas tree.

[pepepeter]

Originally Posted by friendly_jacek

Is the rear diff fluid on the left and transfer on the right? I remember rear diff fluid worse than transfer at 22,000 miles, but not so much as yours. If so, rear diff works very hard and stresses the fluid a lot. This is a remainder for anyone who never did one of those to do it before its too late.

The problem with gear oils is like ATF, if you wait too long and gears adjust to thick goop, changing to new fresh fluids, especially low viscosity synthetics, causes new noises and sometimes failures. I had that in my Subaru and learned a lesson.

BTW, how much metal did you see on the magnetic drain plugs? That is graded in 3-tier system: fuzz, whiskers or Christmas tree.

Those are rear diff pics... Left is straight drain, right is flush with new fluid before refilling with new fliud for rear diff.

The goop on the drain plug was at most 3/8 of an inch... There was a lot, thus the reason to flush it a bit before filling with diff fluid.

I still experience the "mouse wheel squeek". Hope its not serious.