mroxas

RX300 1999 w/ 92.8K miles.

Trouble Shooting from the Manual

1. Oil level (Too high or wrong grade)
2. Rear differential front oil seal (Worn or damaged)
3. Side gear oil seal (Worn or damaged)
4. Companion flange (Loose or damaged)
5. Side gear shaft (Damaged)

Problem:
Rear Differential Leak.
- Left side (Driver Side) - dry.
- Right side (Passenger side) area of Side Gear Shaft bolts connected to Rear Drive Shaft - wet. Also around the fill plug is wet.
- Front (looks okey too).
- Bottom (Wet) - this is where the drain plug is located.

Seems the leak is coming from the right side and drifts down to bottom.

History.
Jan2010 change with Mobil one 75W90. New Lexus Drain& fill plug and gasket.
I notice leak on ground before Sept 4, 2011 (91.8K miles). But on Sep 4, I Inpect maybe about 1ml around the drain plug. Drain only 600ml. Fill one bottle of Royal Purple 75W90 (950ml), making sure it is not overflow/fill with about 5mm before overflow to fill plug. Replace with new plug gasket. Torque 36ft-lb.

Still leaking - I inspect yesterday...

Questions:
1.Can I use 75W140 ? I plan to drain again measure how much is still left after 1.5months and 1.8K miles.
2. Any sealant that can be used ?
3. How an I know if it is Oil Seal or the Side Gear Shaft ?
4. How low from 950ml normal level should I start to worry ? I only drive local most of the time, but also drive back/&forth to new york 120miles, and DC 500 miles.
4. How many hours of labor will it take to change the right Oil Seal ? I will also ask for quotation on $ Oil Seal and $labor.


Thanks a bunch!
-Mike

Lexmex

Thoroughly clean that area off and then take a look at a few hours later and then after driving for a bit to better pinpoint the leak.

1. Yes, you can use 75W140. I've done it with the transfer case when I was in Mexico and there is no issue doing it, and did it to help a similar issue with a leak there. (The oil in the transfer case gets worn faster than the oil in the rear differential).

2. Sealant won't do a thing in the end. That gear oil is still really hot and any use of it will have short-lived effects. I don't use sealant on my tranny pan for example and the one time we did use it in Mexico, it leaked shortly thereafter.

3. That sounds more like a seal issue. The side gear shaft being an issue would likely be more related to some damage along the rest of the axle (bearings, joints, etc.) causing an issue where gear shaft was getting pushed around. Without seeing this directly, tough to fully rule it out, but sounds more like a seal. You might be able to pull back and forth on the side gear shaft to see if there is any bit of play, but really this will only be found out when you have the drive shaft off and are able to get at this piece fully

4. I've driven that stretch of road between DC and NY many times. I'd check the level once a month for now (until you can do a permanent fix). I would not want that level to drop below half. Keep in mind, it's not got as much wear and tear as the transfer case (where the oil level is more important), but you still don't want an issue. I've heard of a few cases with other vehicles where people wound up finding their rear differential/transfer case practically dry and stopping only because they heard a sound, but I would not leave that to chance.

5. That seal is about $17 last time I checked. Not sure what the labor rate is, but it's possible to do this job in about 2 hours.

mroxas

Thanks Lexmex.

Bought the Oil seal, and bring it on one shop but quoted me minimum of $450 to repair... I will look for other shop.

Looking at the manual, got to remove the rear side shaft from wheel, then from the differential. Also the muffler must get out of the way...

I drain last Saturday Nov.5 left of 780ml. Basically loss 170mL after 1.5Kmiles in two months....

Refill with Royal Purple 75W140 and new drain/fill gasket, and leave with it for now. Hope leak to slow down.

But I hope there is something like a Bars Leaks same from the main seal that can be use in rear differential...

Thanks,
-Mike

Lexmex

Let's see where you're at with the 75W140 for the time being.

mroxas

reporting back my rx300 Rear Differential Leak.

Royal Purple 75W140.
Date: From Nov.5 to Dec18'2011. = ~44days.
Mileage: from 92,800 to 94,550 = ~1750miles
Leaks-out total of 150mL. (Leaks slower compare to 75W90)

Lexmex

I still get some leak on occasion from the fill plug (on transfer case on mine) and then it dissipates. Are you still planning to repair it soon?

I wish there was an additive that could be used to help, but I don't know of any that has been successful in the case of the differentials/transfer cases. I know there are some out there, but never have seen them hold up in the long run unlike those used for engine oil.

mroxas

reporting back my rx300 Rear Differential Leak.

Royal Purple 75W140.
Date: 12/18/11 - 2/20/12 = ~2 months.
Mileage: from 94,550 to 98500 = ~4000miles
Leaks-out total of 100mL. (850ml remaining)

Royal Purple 75W140.
Date: 2/20/12 - 5/28/12 = ~3 months.
Mileage: from 98500 to 102520 = ~4000miles
Leaks-out total of 250mL. (700ml remaining)

mroxas

leak looks like it is getting bad on this hot summer season... so I decided to get it into local shop.

bought the OEM (Oil Seal in Side Gear Shaft - 90311-35032 SEAL, TYPE 0 $10.80) + 1 bottle of Royal Purple 75W90.
Local shop charge for two hours job (he charge 95/hr). Worth it, it solves the leak. It is more than a week now without leak.