1st change of transmission & transfer case fluid(s) (1 Viewer)

[GT3Tim]

Its a turbo thing.

Porsche recommends the same thing.
Plugs every 40k.

My Porsche (2021 Cayenne GTS) is every 30K...I have a tune on it too, so it's even more important to stick to that interval, or less.

 

[Warrantero]

I am doing my diffs and xfer case at 15 k to dump all the break in metals out. May be overkill but it’s worth it to me. Using AMSOIL for the diffs and liquid moly for the xfer case.

 

[Bret_T]

Please let us know how the old fluids looked when they were drained.

 

[Warrantero]

Here goes, my GX has 16706 miles, just did the front/rear diffs today, have liquid moly 75W on order for the transfer case.

Dropped the spare tire made it a lot easier to drain and fill. Need a 24 mm socket to remove. Man it was tight! Cripes! Used AMSOIL 75w-85. Squeeze bags worked well on rear diffs. Used a little over 7 qts.

Front diff you will need a 10mm Allen socket for the fill and drain plugs they are torqued down too, it took a bit to break them loose.

Front and rear Drain plugs had a little bit of material on it looked alright to me.

Recommend a fluid pump for the front diff not much room to get a squeeze bag in there. I don’t have a lift so I removed the skid plate and gave me room to work. Just shy of two quarts to fill.

Looks like the transfer case is a 10 mm socket to remove fill and drain plugs. You will need a fluid plump for the transfer case also.

I tightened plugs to 20ft lbs, seemed to be pretty snugged down.

12157-10010 and 90430-24017 are the parts numbers for drain and fill plug gaskets on the front differential.

12157-10010 is the part number for drain and fill plug gaskets on rear differential.

Transfer case drain and fill plug gaskets are 90430-18008. Hope this helps.

 

[Bret_T]

Any thoughts on using the more available 75W-90 GL-5? 75W-85 GL-5 is difficult to find and over twice as expensive.

 

[Warrantero]

You would probably take a very small hit in gas mileage, as long as it meets the spec. I used amsoil to meet the 75w-85 spec.

 

[1mikezat1]

I spoke with a retired Toyota/Lexus master mechanic a while ago and asked for his advice regarding gearbox and transfer case fluids.

According to him, gearboxes and transfer cases, especially those manufactured in Japan, tend to have very tight internal gear tolerances when new. Because of this, fluid selection during the early service intervals can be important.

For vehicles operated under what Toyota considers "special driving conditions," such as frequent short trips under 5 miles, heavy stop-and-go traffic, extensive idling, towing, driving in extremely hot or cold temperatures, or operating on dusty or unpaved roads, he did not recommend using 75W-90 gear oil for the first two fluid changes. His concern was that the higher viscosity could create additional resistance, not being able to "sneak" in required volume between moving parts, and potentially generate extra heat during the initial break-in period.

For normal street driving, he recommended staying with Toyota OEM fluid for the first gearbox and transfer case fluid change. For the second change, he suggested that a fluid such as Amsoil or Ravenol 75W-85 would be acceptable.

After the first two fluid changes, he said the choice between 75W-85 and 75W-90 becomes less critical, and that using 75W-90 afterward should not present an issue.

My recommendation is to do the gearbox and transfer case fluid changes yourself if you are comfortable doing the work, but buy Toyota OEM fluid directly from a dealer. OEM fluids are ridiculously expensive, but if you do the work yourself, the pain is much less. Do not buy OEM fluids from Amazon or eBay; there are too many counterfeits.

 

[Bret_T]

Thanks for the information. I'll stick with the 75W-85 GL-5. I looked back at my old 2017 Land Cruiser maintenance records. It turns out that I used both Ravenol and Red Line 75W-85 GL-5. Since I never had an issue with that vehicle, I'll go with the Red Line again. I just can't stomach the ripoff price for the Toyota 75W-85 GL-5. I have a partial quart of the Red Line left and the bottle label indicates that it meets the Toyota specification.

 

[Warrantero]

Thanks for the information. I'll stick with the 75W-85 GL-5. I looked back at my old 2017 Land Cruiser maintenance records. It turns out that I used both Ravenol and Red Line 75W-85 GL-5. Since I never had an issue with that vehicle, I'll go with the Red Line again. I just can't stomach the ripoff price for the Toyota 75W-85 GL-5. I have a partial quart of the Red Line left and the bottle label indicates that it meets the Toyota specification.

I used the AMSOIL 75w-85 GL5 and went with Redline MT/ML 70/75 which meets the Toyota LF spec per Redlines website. I was going to use Liquid Moly but the Redline was available locally.

 

[Bret_T]

I changed the front and rear differential oil yesterday at 29,670 miles. The rear oil looked surprisingly clean while the front oil was pretty dirty. The front took about 1.3 quarts. The rear took about seven. If you let the rear wheels hang when using a lift or jack stands, the rear differential will hang downward towards the rear of the vehicle. This will result in not enough oil going in. I have a lift, but had to put all four wheels on the ground in order to get the proper amount of oil in.

 

[cmfhsu]

I changed the front and rear differential oil yesterday at 29,670 miles. The rear oil looked surprisingly clean while the front oil was pretty dirty. The front took about 1.3 quarts. The rear took about seven. If you let the rear wheels hang when using a lift or jack stands, the rear differential will hang downward towards the rear of the vehicle. This will result in not enough oil going in. I have a lift, but had to put all four wheels on the ground in order to get the proper amount of oil in.

How much extra gear oil went into the rear diff after you set the car down on the suspension? I'm hoping it's only like an ounce or two, because I almost guarantee this is how nearly every dealership & shop will do the service. Nobody's gonna crawl underneath the car for you or take up valuable space on their alignment rack to do it. And with almost 2 gallons of gear oil in the rear diff, I'm not too worried about 2 fl oz.

I did my front & rear diff as well as an ATF drain and fill at ~12k miles, but I did do everything while the vehicle was lifted with the frame level, since the ATF needs level and it's the most sensitive to fluid quantity.

Front and rear diff fluid was mostly freshly golden, without any big chunks from the rear diff like Car Care Nut found in his Tundra. That's a relief. I did get a bunch of smaller shavings and bits from the rear, as you'd expect, and almost nothing from the front.

ATF drain & fill made a pretty big difference, IMO. The fluid seemed to be in decent condition when drained, but I can tell the friction coefficient of the fluid changed pretty dramatically. 6 quarts of fresh ATF (not because that's how much it needed - purely because my dealer gave me the wrong crush washers and I needed to check the level twice, wasting a quart) caused my Torque Converter Clutch to slip a little bit while it was re-learning and it's noticeably smoother when shifting & locking the TCC now, especially when towing. Would recommend draining the factory ATF and replacing with fresh Genuine WS ATF if you get the opportunity; get some of that nasty break in clutch dust out of there.

Pro tip for anybody doing an ATF drain and fill - either make sure you have a really good, fresh 6mm hex bit socket (i.e. tool truck brand with no damage) or buy a 6mm GripEdge hex socket (they manufacture the highly regarded MAC RBRT bits), like the one you can find in this set. Toyota calls for 30 foot pounds on a 6mm hex drain bolt and there is no way to put that much torque on the bolt without rounding out the hex hole unless you have a bit that fits absolutely perfectly without any slop. I'm going to have to get a new bolt next time I do another ATF drain & fill because my trusty old Pittsburgh socket started to round it out starting at 20-25 foot pounds.

 

[Bret_T]

How much extra gear oil went into the rear diff after you set the car down on the suspension? I'm hoping it's only like an ounce or two, because I almost guarantee this is how nearly every dealership & shop will do the service. Nobody's gonna crawl underneath the car for you or take up valuable space on their alignment rack to do it. And with almost 2 gallons of gear oil in the rear diff, I'm not too worried about 2 fl oz.

I only put 2 quarts in when it was on the lift. That was a big mistake as it was harder to pump the oil in when the vehicle was on the garage floor due to less space. I would think that dealerships/shops would use one of those drive on lifts for this type of service. If they fill it while on an asymmetrical lift like I have, they’ll come up very short.

 

[1mikezat1]

I got cheap rhino ramps supplemented with cheap jack stands, so my tires are not hanging when I do maintenance. This gives me plenty of clearance even w my beer belly.

 

[cmfhsu]

I got cheap rhino ramps supplemented with cheap jack stands, so my tires are not hanging when I do maintenance. This gives me plenty of clearance even w my beer belly.

Careful, though - checking the ATF requires the frame to be level, so the natural forward rake of the suspension might leave you with an inaccurate amount of fluid. And we've seen that modern transmissions can be sensitive to fluid differences of a few fluid ounces. Drop a bubble level on the running board or the underside of the frame before doing an ATF job.

Differentials and transfer cases don't care, though.

 

[Bret_T]

Careful, though - checking the ATF requires the frame to be level, so the natural forward rake of the suspension might leave you with an inaccurate amount of fluid. And we've seen that modern transmissions can be sensitive to fluid differences of a few fluid ounces. Drop a bubble level on the running board or the underside of the frame before doing an ATF job.

My wife had a Sequoia. I had a local dealership change the transmission fluid. After that, the transmission consistency had trouble shifting when the vehicle was cold while going up hill on cold days. I took it back to the dealership and had them recheck the fluid level. They claimed it was spot on. The vehicle still had the problem, so I bought some transmission fluid myself and added half a quart. The failure to shift problem immediately went away.

 

[1mikezat1]

Is the GX550 transmission a sealed type, and is its dipstick accessible from the bottom? If so, the fill level must then be adjusted based on the fluid temperature. I bet the dealership did not level the SUV or use an OBD reader to check the temperature and calculate the proper level. When I change the ATF in a sealed transmission, it is always a long process. I drain the old ATF into a measuring container, then let it sit overnight right next to the new ATF so both fluids are at the same temperature by morning. This way, in the morning, when the old ATF shrinks, I can see exactly how much was drained and easily measure how much new ATF I need to use right away before the temp changes.

 

[cmfhsu]

Is the GX550 transmission a sealed type, and is its dipstick accessible from the bottom? If so, the fill level must then be adjusted based on the fluid temperature. I bet the dealership did not level the SUV or use an OBD reader to check the temperature and calculate the proper level. When I change the ATF in a sealed transmission, it is always a long process. I drain the old ATF into a measuring container, then let it sit overnight right next to the new ATF so both fluids are at the same temperature by morning. This way, in the morning, when the old ATF shrinks, I can see exactly how much was drained and easily measure how much new ATF I need to use right away before the temp changes.

The GX uses Toyota's standard modern "sealed" transmission approach.

There's a stand pipe that screws into the pan drain hole which is a very specific length & does require you to check the oil while the vehicle is running, frame level, at a specific temperature. There's a pretty easy procedure to put the vehicle into ATF check mode which indicates when you're at the correct fluid temperature, and it requires no scantools or pin shorting at all. I verified this gear shifter song & dance approach against the ATF temperature values from my Autel scantool. This video documents it well:



I'm a little nervous about the "measure what comes out and refill" approach, as other Toyota owners have seen that their transmissions were underfilled at the factory, and it's hard to get exactly the same amount of fluid back in - though my GX appears to have been exactly correctly filled. Given how easy it is to get into temp check mode, that's what I'd recommend.

 

[cmfhsu]

One more tip for an ATF drain & fill which I forgot - the ATF warms up pretty quickly and blows through the specified temperature range in like 2-4 minutes, so you need to move fast.

I used Car Care Nut's recommended technique, where he started the car, put it into temp check mode, and then opened the stand pipe drain plug while everything was still cold (but running) and let any excess fluid drain until it nearly stopped trickling. He then reinstalled the plug and waited for the fluid to heat up & expand to the specified temperature before opening the plug again for the final level check.

This lets you quickly set the level while it's at the right temperature without waiting for a bunch of excess fluid to drain. If I didn't do this, I think it's likely that the temperature would have exceeded the specified maximum before the fluid drained to the correct level, since I put a decent amount of extra fluid in to mix around and avoid having to open the fill plug again. I drained the ATF after the vehicle sat overnight; about 5 quarts came out and I put 6 quarts back in, requiring me to drain about an extra quart of fluid before I hit the level check temperature.