Hey I love being on vacation, I got plenty of time to give some love to my baby, and post some DIYs!!!
My car is a '98 Camry 4cyl with 290 000 kilometers (around 180 000 miles), not all models of Camry have their Differential fluid in a separate casing, but if yours does, here's how you can change it. It's an easy job, but a messy one. This job shouldn't be overlooked, as it is as important to change the diff fluid than it is changing the tranny fluid.
Things you will need :
1.Engine degreaser / LINT FREE cloth : always a good idea to work on clean parts around the tranny.
2.2 Quarts of Dextron III auto transmission fluid, 1.7 Qts actually go in.
3. A piece of rubber tube, I used a 3 ft (I think) piece of fuel hose.
4.A small funnel that will fit in the rubber hose
5.A 3/8 hex bit or Allen wrench and a 17 MM socket or open wrench
6.A bucket for the used fluid.
THE PROCESS :
1. Securely jack the car up on tracks or jackstands, then carefully clean up the area around the differential drain plug and fill plug with engine degreaser.
Red = Drain plug
Green = Fill plug.
2. Use the Hex bit/Allen wrench to unscrew the drain plug and let the used oil drip in a bucket, then remove the fill plug with the 17 MM socket and a ratchet. I'm unscrewing the fill plug on the picture and the drain plug is still there, but yours shouldn't be, I just forgot to take the picture. It will be easy to access/unscrew by going around the exhaust pipe with your arm.
3.Put the drain plug back in securely, be careful not to bring up any crud/dust/foreing objects on the plug or around the area where it goes.
4.Now grab the piece of hose and push the funnel in one of it's ends until it securely in place. Then from the top of the engine snake the other end of the hose down until you can see it underneath the car, mine was right between the throttle body and firewall. Then crawl back underneath your beloved Camry, grab the loose end of the hose and put it in the fill plug, again be careful for rocks and foreign objects if the hose touched the ground. Don't push it too far in, just to it stays there while you pour the new oil in, you can also have a friend help you out on that. PUT YOUR OIL BUCKET BACK UNDERNEATH THE DIFFERENTIAL CASE, cause it's gonna drip when it's full.
5.You can put a full quart of Dextron III in there without looking, then start pouring down the second quart slower until you see oil dripping out of the fill plug and in the bucket, my second quart was just below half when that happened. There is no dipstick or anything to check the differential fluid level, the fill plug hole IS the correct level so when it drips out of it, it's full. My car was jacked up on tracks, and not jackstands so it wasn't level. When I pulled the hose out of the fill plug it started dripping out of the fill plug so I capped it off quickly, just a little "overfill" to compensate for the fact that the front of the car was higher than the back end so it would be alright when back on level ground. Re-tighten the fill plug securely and you are done. You can now witness a swarm of hot chicks in bikini running up your driveway, attracted by freshly changed differential fluid!!
Another well spent afternoon. Again, any questions/comments/additions are welcome.
My car is a '98 Camry 4cyl with 290 000 kilometers (around 180 000 miles), not all models of Camry have their Differential fluid in a separate casing, but if yours does, here's how you can change it. It's an easy job, but a messy one. This job shouldn't be overlooked, as it is as important to change the diff fluid than it is changing the tranny fluid.
Things you will need :

1.Engine degreaser / LINT FREE cloth : always a good idea to work on clean parts around the tranny.
2.2 Quarts of Dextron III auto transmission fluid, 1.7 Qts actually go in.
3. A piece of rubber tube, I used a 3 ft (I think) piece of fuel hose.
4.A small funnel that will fit in the rubber hose
5.A 3/8 hex bit or Allen wrench and a 17 MM socket or open wrench
6.A bucket for the used fluid.
THE PROCESS :
1. Securely jack the car up on tracks or jackstands, then carefully clean up the area around the differential drain plug and fill plug with engine degreaser.
Red = Drain plug
Green = Fill plug.

2. Use the Hex bit/Allen wrench to unscrew the drain plug and let the used oil drip in a bucket, then remove the fill plug with the 17 MM socket and a ratchet. I'm unscrewing the fill plug on the picture and the drain plug is still there, but yours shouldn't be, I just forgot to take the picture. It will be easy to access/unscrew by going around the exhaust pipe with your arm.

3.Put the drain plug back in securely, be careful not to bring up any crud/dust/foreing objects on the plug or around the area where it goes.
4.Now grab the piece of hose and push the funnel in one of it's ends until it securely in place. Then from the top of the engine snake the other end of the hose down until you can see it underneath the car, mine was right between the throttle body and firewall. Then crawl back underneath your beloved Camry, grab the loose end of the hose and put it in the fill plug, again be careful for rocks and foreign objects if the hose touched the ground. Don't push it too far in, just to it stays there while you pour the new oil in, you can also have a friend help you out on that. PUT YOUR OIL BUCKET BACK UNDERNEATH THE DIFFERENTIAL CASE, cause it's gonna drip when it's full.

5.You can put a full quart of Dextron III in there without looking, then start pouring down the second quart slower until you see oil dripping out of the fill plug and in the bucket, my second quart was just below half when that happened. There is no dipstick or anything to check the differential fluid level, the fill plug hole IS the correct level so when it drips out of it, it's full. My car was jacked up on tracks, and not jackstands so it wasn't level. When I pulled the hose out of the fill plug it started dripping out of the fill plug so I capped it off quickly, just a little "overfill" to compensate for the fact that the front of the car was higher than the back end so it would be alright when back on level ground. Re-tighten the fill plug securely and you are done. You can now witness a swarm of hot chicks in bikini running up your driveway, attracted by freshly changed differential fluid!!
Another well spent afternoon. Again, any questions/comments/additions are welcome.