Besides reading the manual, are there any thoughts here on when to first change the transmission and transfer case fluids for the Overtrail? 2025 GX 550 Overtrail. Assume no extended idling or other hard driving conditions for the early miles on the truck during "break in" period.
1st change of transmission & transfer case fluid(s)
- Thread starter Colby82
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SandMonster
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Would be curious to know as well if anyone in this community has any thoughts on this.
The warranty and service guide has "recommended" service intervals and "special" operating service intervals. The "recommended" service intervals only indicate that they should just be inspected, not replaced. That doesn't seem realistic in my opinion giving that fluids do deteriorate. The "special" operating service intervals indicate that the transfer case oil should be replaced every 30,000 miles and the automatic transmission fluid should be replaced every 60,000 miles. If you drive under the special conditions, do that. However, since my wife just sticks to the streets, I decided to go somewhere in between. I'll change the transfer case oil at 60,000 miles and every 60,000 thereafter. I'll change the transmission fluid at 90,000 miles and every 60,000 miles thereafter. The same logic holds for some other maintenance items such as changing the front and rear differential oils. I did this with my wife's 2018 Land Cruiser and had no issues. I traded it in at 162,250 miles. The chart I created below shows the initial service mileage and the interval thereafter.
| Schedule | Actual | |||||
| Mileage | Mileage | Service | Date | Frequency | ||
| 5,000 | Change Oil and Filter | Every 5,000 miles | ||||
| 10,000 | Rotate Tires | Every 10,000 miles | ||||
| 15,000 | Lubricate Propeller Shaft | Every 15,000 miles | ||||
| 15,000 | Torque Propeller Shaft Bolts | Every 15,000 miles | ||||
| 30,000 | Change Brake Fluid | Every 30,000 miles | ||||
| 30,000 | Change Front Differential Oil | Every 30,000 miles | ||||
| 30,000 | Change Rear Differential Oil | Every 30,000 miles | ||||
| 30,000 | Replace Cabin Air Filter | Every 30,000 miles | ||||
| 30,000 | Replace Engine Air Filter | Every 30,000 miles | ||||
| 40,000 | Replace Spart Plugs | Every 40,000 miles | ||||
| 60,000 | Replace Transfer Case Oil | Every 60,000 miles | ||||
| 90,000 | Replace Automatic Transmission Fluid | Every 60,000 miles | ||||
| 100,000 | Replace Drive Belts | Every 100,000 miles | ||||
| 100,000 | Replace Engine/Intercooler Coolant | Every 50,000 miles | ||||
| 100,000 | Replace Radiator Hoses | Every 100,000 miles |
I'm planning on having the dealer do the transfer case & rear diff at 25 or 30k miles.
I found it on page 48 in the 2025 GX 550 Warranty and Services Guide. I'm all for a good laugh, but why is that funny? Page 50 indicates that the spark plugs are required to be replaced at 80,000 miles and page 52 indicates that they're required to be replaced at 120,000 miles.
Don't forget the front differential.
These high compression engines really do a number on spark plugs. Same thing with my IS. I tried to wait 10k more miles but it started to run poorly.
I knew there had to be a reason and that makes sense. I'll comply.
LOL, I won't, meant to type front & rear diff
jeez, 40k miles for changing plugs. I believe my Tundra with the 5.7 has spark plug change interval at 120k miles, which I did myself about 5 years ago. They still looked new. Hope it's easy to change plugs on the GX. I prefer to do plug changes myself and properly torque. Once had a dealer change plugs on a Grand Cherokee with 5.2 V-8 and 2 of the plugs were so tight they snapped off. I had to use an "easy-out" and torch to get them out. Never again...
It's not impossible, but some of the plugs are a bit of a squeeze and it's definitely way more involved than what I had to do on my Mazda which took all of 10 minutes. Depending what the dealers are going to charge when I need it done will determine if I do it myself or not.
You guys need better reading comprehension. According to the table in post#3 it's only the "spart plugs" that need to be changed at 40k. That's totally normal.
Hell, I change my spart plugs more often than underwear.
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