Rear Differential & Transfer Case DIY
09-04-18, 06:44 PM
#211
Lexus Test Driver
That looks good to me, Dan. As I recall, the rear diff and the (front) transfer case each used about a quart of gear oil. I didn't measure exactly; I just filled until it overflowed. My dealer had me add a little 4-oz. bottle of GM torque-sensing differential additive ADDT (08800-BOPCKT0, about $15) in each as the first step in refilling the fluid. That's what they use each time.
09-05-18, 02:13 PM
#212
Driver School Candidate
UPDATE: Changing Transfer Case and Rear Differential fluid on 1st Gen RX300
I know this is a super old thread but I still have my '02 RX300 and do my own work. These forums have been a massive blessing to me in keeping my baby in tip-top at 144,000 miles. I spent two months researching how to change the rear differential and front transfer case gear oil. There is good info (from Lexmex and others) but it is not complete and there is also a massive amount of misinformation on changing these fluids properly. I have figured it out and would happy to fill in the important details to anyone looking to change their gear oil on 1st Gen RX300. Please tell me if you'd like me to share as there are many details I had to figure out with the help of a local Lexus mechanic. Also, there is serious misinformation on what is the transfer case and what is the differential in front. They are NOT interchangeable terms:
1) The FRONT DIFFERENTIAL works with the transmission and shares the Type IV fluid. You fill through the transmission fluid fill tube.
2) The TRANSFER CASE uses GL-5 or Amsoil 75W-90 gear oil.
3) The REAR DIFFERENTIAL uses GL-5 or Amsoil 75W-90 gear oil (the same oil used by the TRANSFER CASE).
1) The FRONT DIFFERENTIAL works with the transmission and shares the Type IV fluid. You fill through the transmission fluid fill tube.
2) The TRANSFER CASE uses GL-5 or Amsoil 75W-90 gear oil.
3) The REAR DIFFERENTIAL uses GL-5 or Amsoil 75W-90 gear oil (the same oil used by the TRANSFER CASE).
OK, I posted this yesterday and there seems to be quite a bit of interest still. Let me give a summary of my three months of research and actually changing these fluids. MASSIVE thanks to Lexmex who gives the most complete run down on how to do this, I'm adding to his write up and a few clarifications of things he left out:
I changed my rear diff and transfer case fluid for the first time at 143,000 miles.
REAR DIFF: Use a 10mm hex socket to remove both the rear diff plugs. Easy job. You may need some serious leverage to get them out but i did mine with no lift and a standard 3/8" Craftsman ratchet with 5" extension. The fluid was like new with almost no metal on the plug magnet. Used the correct 12157-10010 crush gaskets on both plugs when I replaced them. Put the crush part against the case. I did without torque wrench. After much research, I used Amsoil Severe Gear 75w-90. It took a little more than 1 quart. I bought a $7 hand pump with 16" attached hose off Amazon to fill. Definitely get this. I drilled a hole through top of Amsoil lid so the pump fit in perfectly.
Transfer Case (not "front differential"): Fill bolt was easy. I used a friend's lift and 1/2" drive 15/16" size socket (bought from Home Depot) and a 1/2" to 3/8" adapter to fit my 3/8" ratchet. I used a total of 12" of extension to get to it. It took some might but it let go pretty quickly. Turn to left. The drain bolt was another story, OH MY. What were these Japanese engineers thinking? Some have suggested the Ace Hardware Pro-Line 15/16" box wrench. This does NOT work. I bought this wrench (special order) but had to have a friend grind the face flush with the teeth AND I also had him grind the entire box end way down to make it much thinner. Once you do this, you are all set. The ground down box end fits perfectly. I used a 12-point wrench but a 6-point will be fine also as the plug is 6-point. With both the fill and drain plugs removed, I let it drain for 30 minutes to make sure it all came out. Guess what? After 143,000 miles it looked like new fluid! No bad smell, no discoloration. I guess I have babied my RX more than I thought. The plug magnet had very little metal on it. One wipe and it was good as new. Now onto the gaskets. I had to talk to SIX mechanics to get the correct gaskets, got much misinformation along the way and bought many wrong gaskets/washers. Here you go with correct info: The Transfer Case fill and drain plugs (both) use the EXACT same crush gaskets as the rear diff fill and drain plugs: 12157-10010 crush gasket. Put the crush part against the case. I did without torque wrench. As in the rear, I used Amsoil Severe Gear 75w-90. It took exactly 1 quart.
For Both: After draining, replace drain plug, fill with gear oil until it drips then replace fill plug.
I hope this helps my RX300 buddies. My 2002 is running like new at 144,000 miles. I keep fluids changed regularly. I have yet to change the plugs and have no error codes. I use regular dino 5w-30 and always use a bottle of Bestline Engine additive. I do work for this company and can tell you it is the only one that has been thoroughly tested. I only use WIX 51348 oil filters and choose this exact filter after many weeks of research.
09-05-18, 02:36 PM
#213
Driver School Candidate
That looks good to me, Dan. As I recall, the rear diff and the (front) transfer case each used about a quart of gear oil. I didn't measure exactly; I just filled until it overflowed. My dealer had me add a little 4-oz. bottle of GM torque-sensing differential additive ADDT (08800-BOPCKT0, about $15) in each as the first step in refilling the fluid. That's what they use each time.
@trhs75: Thank you for for this info. I have a 2002 and i don't think the LSD was an option. I have to do a friends 2001 RX300 gear fluid change. Would you recommend this additive (Amazon part number: 88900330) even if is not an LSD or is this overkill? Would you use it in both rear diff and the transfer case?
09-05-18, 09:05 PM
#214
Lexus Test Driver
I would use in both, Dan, but I am no pro by any means. My dealer didn't even ask if I had LSD (both of my 99's have it) when they recommended the additive. For minimal cost (considering how long the fluid will be in there), I think it was worth it. Oh boy, do I remember trying to get that transfer case drain bolt off. My solution was similar to yours -- grinding down a wrench to fit in there. Goofy design!!
09-06-18, 10:11 AM
#215
Driver School Candidate
UPDATE 2: Pictures of modified tool to remove TC drain plug
----------------------------------------------------------------------------------------------------------------
OK, I posted this yesterday and there seems to be quite a bit of interest still. Let me give a summary of my three months of research and actually changing these fluids. MASSIVE thanks to Lexmex who gives the most complete run down on how to do this, I'm adding to his write up and a few clarifications of things he left out:
I changed my rear diff and transfer case fluid for the first time at 143,000 miles.
REAR DIFF: Use a 10mm hex socket to remove both the rear diff plugs. Easy job. You may need some serious leverage to get them out but i did mine with no lift and a standard 3/8" Craftsman ratchet with 5" extension. The fluid was like new with almost no metal on the plug magnet. Used the correct 12157-10010 crush gaskets on both plugs when I replaced them. Put the crush part against the case. I did without torque wrench. After much research, I used Amsoil Severe Gear 75w-90. It took a little more than 1 quart. I bought a $7 hand pump with 16" attached hose off Amazon to fill. Definitely get this. I drilled a hole through top of Amsoil lid so the pump fit in perfectly.
Transfer Case (not "front differential"): Fill bolt was easy. I used a friend's lift and 1/2" drive 15/16" size socket (bought from Home Depot) and a 1/2" to 3/8" adapter to fit my 3/8" ratchet. I used a total of 12" of extension to get to it. It took some might but it let go pretty quickly. Turn to left. The drain bolt was another story, OH MY. What were these Japanese engineers thinking? Some have suggested the Ace Hardware Pro-Line 15/16" box wrench. This does NOT work. I bought this wrench (special order) but had to have a friend grind the face flush with the teeth AND I also had him grind the entire box end way down to make it much thinner. Once you do this, you are all set. The ground down box end fits perfectly. I used a 12-point wrench but a 6-point will be fine also as the plug is 6-point. With both the fill and drain plugs removed, I let it drain for 30 minutes to make sure it all came out. Guess what? After 143,000 miles it looked like new fluid! No bad smell, no discoloration. I guess I have babied my RX more than I thought. The plug magnet had very little metal on it. One wipe and it was good as new. Now onto the gaskets. I had to talk to SIX mechanics to get the correct gaskets, got much misinformation along the way and bought many wrong gaskets/washers. Here you go with correct info: The Transfer Case fill and drain plugs (both) use the EXACT same crush gaskets as the rear diff fill and drain plugs: 12157-10010 crush gasket. Put the crush part against the case. I did without torque wrench. As in the rear, I used Amsoil Severe Gear 75w-90. It took exactly 1 quart.
For Both: After draining, replace drain plug, fill with gear oil until it drips then replace fill plug.
I hope this helps my RX300 buddies. My 2002 is running like new at 144,000 miles. I keep fluids changed regularly. I have yet to change the plugs and have no error codes. I use regular dino 5w-30 and always use a bottle of Bestline Engine additive. I do work for this company and can tell you it is the only one that has been thoroughly tested. I only use WIX 51348 oil filters and choose this exact filter after many weeks of research.
OK, I posted this yesterday and there seems to be quite a bit of interest still. Let me give a summary of my three months of research and actually changing these fluids. MASSIVE thanks to Lexmex who gives the most complete run down on how to do this, I'm adding to his write up and a few clarifications of things he left out:
I changed my rear diff and transfer case fluid for the first time at 143,000 miles.
REAR DIFF: Use a 10mm hex socket to remove both the rear diff plugs. Easy job. You may need some serious leverage to get them out but i did mine with no lift and a standard 3/8" Craftsman ratchet with 5" extension. The fluid was like new with almost no metal on the plug magnet. Used the correct 12157-10010 crush gaskets on both plugs when I replaced them. Put the crush part against the case. I did without torque wrench. After much research, I used Amsoil Severe Gear 75w-90. It took a little more than 1 quart. I bought a $7 hand pump with 16" attached hose off Amazon to fill. Definitely get this. I drilled a hole through top of Amsoil lid so the pump fit in perfectly.
Transfer Case (not "front differential"): Fill bolt was easy. I used a friend's lift and 1/2" drive 15/16" size socket (bought from Home Depot) and a 1/2" to 3/8" adapter to fit my 3/8" ratchet. I used a total of 12" of extension to get to it. It took some might but it let go pretty quickly. Turn to left. The drain bolt was another story, OH MY. What were these Japanese engineers thinking? Some have suggested the Ace Hardware Pro-Line 15/16" box wrench. This does NOT work. I bought this wrench (special order) but had to have a friend grind the face flush with the teeth AND I also had him grind the entire box end way down to make it much thinner. Once you do this, you are all set. The ground down box end fits perfectly. I used a 12-point wrench but a 6-point will be fine also as the plug is 6-point. With both the fill and drain plugs removed, I let it drain for 30 minutes to make sure it all came out. Guess what? After 143,000 miles it looked like new fluid! No bad smell, no discoloration. I guess I have babied my RX more than I thought. The plug magnet had very little metal on it. One wipe and it was good as new. Now onto the gaskets. I had to talk to SIX mechanics to get the correct gaskets, got much misinformation along the way and bought many wrong gaskets/washers. Here you go with correct info: The Transfer Case fill and drain plugs (both) use the EXACT same crush gaskets as the rear diff fill and drain plugs: 12157-10010 crush gasket. Put the crush part against the case. I did without torque wrench. As in the rear, I used Amsoil Severe Gear 75w-90. It took exactly 1 quart.
For Both: After draining, replace drain plug, fill with gear oil until it drips then replace fill plug.
I hope this helps my RX300 buddies. My 2002 is running like new at 144,000 miles. I keep fluids changed regularly. I have yet to change the plugs and have no error codes. I use regular dino 5w-30 and always use a bottle of Bestline Engine additive. I do work for this company and can tell you it is the only one that has been thoroughly tested. I only use WIX 51348 oil filters and choose this exact filter after many weeks of research.
After a request, here are four detailed pictures of the Ace Pro Series 15/16" box wrench I modified to fit the 2002 RX300 Transfer Case drain plug. The box end has been ground to make the teeth flush. Also, the box end outer wall mass has been reduced by 50%. It's the only way to fit the tool into that ridiculous drain plug! See pics below. Unless someone knows of an absurdly thin 15/16" with a 50% reduced box end profile, you'll have to do the same. It took 20 minutes on a friends grinder. No big deal. You don't have to use the Ace Hardware wrench but it worked for me:
Full wrench. 15/16"
Side of modified box end
Ace Pro Series
Detailed view and description of modifications
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goomz (09-06-18)
05-12-19, 05:26 AM
#219
Driver School Candidate
Pls, what is the consequence of using old oil
Sorry to drag you guys backwards, I am a new owner of rx300 2001. My previous Rav4 didn't have the Differential fluid thing, at least to the best of my knowledge.
So I have been using my rx300 for seven months now and am wondering if there is need to change this fluid now.
What is or are the consequences if the fluid isn't change on time. Thanks boss
So I have been using my rx300 for seven months now and am wondering if there is need to change this fluid now.
What is or are the consequences if the fluid isn't change on time. Thanks boss
05-12-19, 09:34 AM
#220
Super Moderator
Thread Starter
Sorry to drag you guys backwards, I am a new owner of rx300 2001. My previous Rav4 didn't have the Differential fluid thing, at least to the best of my knowledge.
So I have been using my rx300 for seven months now and am wondering if there is need to change this fluid now.
What is or are the consequences if the fluid isn't change on time. Thanks boss
So I have been using my rx300 for seven months now and am wondering if there is need to change this fluid now.
What is or are the consequences if the fluid isn't change on time. Thanks boss
In my experience, you won't notice much, not even on MPG. Where I did notice a difference is in the 1/4 mile when I raced in Mexico and I did notice the shifts were quicker were a bit sharper. However, it's not like the tranny where you really need to be more religious and watching.
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3kay945 (05-12-19)
05-12-19, 03:05 PM
#221
Driver School Candidate
It's only on AWD that you have this, not FWD that's why you probably did not have in your RAV4.
In my experience, you won't notice much, not even on MPG. Where I did notice a difference is in the 1/4 mile when I raced in Mexico and I did notice the shifts were quicker were a bit sharper. However, it's not like the tranny where you really need to be more religious and watching.
In my experience, you won't notice much, not even on MPG. Where I did notice a difference is in the 1/4 mile when I raced in Mexico and I did notice the shifts were quicker were a bit sharper. However, it's not like the tranny where you really need to be more religious and watching.
Thanks boss, I will still have to do it soon.
06-07-20, 09:42 PM
#222
I couldn't get the Ace Pro wrench locally. So I went wrench hunting today (HD, Autozone, then NAPA) and found that the Lowes Kobalt 15/16-in 12-point combo wrench works! Item #337622 Model #85616
I placed the wrench then hammered in a wood stake (the triangular side that goes into the ground or you can use any wedge shaped material that's not too hard), the key is that it needs to get wedged right on top of the drain plug bolt head (also on the box wrench) and between the chassis/body member. This way it keeps the box wrench on the drain plug and prevents it from slipping off! I did lift the RX high for extra working space and had Heavy Duty jack stands plus hollow blocks as back-ups so the front end was not going anywhere.
My only concern now is that the recommended NAPA replacement magnetic bolt pn: 704-1923 is too long. Have many used this? I guess I will use the plastic washer that it came with plus the crush washer. Hope this does not leak when used this way or is too long and something inside hits it.
Thoughts/Comments on this? Has anyone I stuck a finger in there to see how much clearance? I guess I'll check tomorrow. Or is an alternative available at other parts stores? It's a M18x1.5 so that's common but not sure there's a shorter one that's magnetic.
Thx!
I placed the wrench then hammered in a wood stake (the triangular side that goes into the ground or you can use any wedge shaped material that's not too hard), the key is that it needs to get wedged right on top of the drain plug bolt head (also on the box wrench) and between the chassis/body member. This way it keeps the box wrench on the drain plug and prevents it from slipping off! I did lift the RX high for extra working space and had Heavy Duty jack stands plus hollow blocks as back-ups so the front end was not going anywhere.
My only concern now is that the recommended NAPA replacement magnetic bolt pn: 704-1923 is too long. Have many used this? I guess I will use the plastic washer that it came with plus the crush washer. Hope this does not leak when used this way or is too long and something inside hits it.
Thoughts/Comments on this? Has anyone I stuck a finger in there to see how much clearance? I guess I'll check tomorrow. Or is an alternative available at other parts stores? It's a M18x1.5 so that's common but not sure there's a shorter one that's magnetic.
Thx!
06-16-20, 02:39 AM
#223
Driver School Candidate
Hey Enz. I'm glad you found a wrench that worked. I wouldn't have done the wood stake hammering part but if that works, great. The wrench I have listed is still available at Ace hardware. I recommend that others use this specific wrench and have it modified as I detail in my post.
Regarding changing the drain plug - I definitely would not. Differential fluid only needs to be changed every 75,000 to 150,000 miles meaning not very often. The stock plug is fine.
Regarding changing the drain plug - I definitely would not. Differential fluid only needs to be changed every 75,000 to 150,000 miles meaning not very often. The stock plug is fine.
06-22-20, 01:48 PM
#224
Hey Enz. I'm glad you found a wrench that worked. I wouldn't have done the wood stake hammering part but if that works, great. The wrench I have listed is still available at Ace hardware. I recommend that others use this specific wrench and have it modified as I detail in my post.
Regarding changing the drain plug - I definitely would not. Differential fluid only needs to be changed every 75,000 to 150,000 miles meaning not very often. The stock plug is fine.
Regarding changing the drain plug - I definitely would not. Differential fluid only needs to be changed every 75,000 to 150,000 miles meaning not very often. The stock plug is fine.
I did replace it with the NAPA magnetic bolt, I stuck a finger in there and there was a lot of clearance plus most of the bolt length was eaten up by the wall thickness of the transfercase so there really wasn't much protruding into the cavity.
edit: I see that it took you 20 minutes to grind it down. What's there to prevent the wrench from slipping off even if you grind it down? Again, IMHO its not necessary to grind it down if you wedge something in there to keep the wrench in place. It's only needed to break the bolt, you can take the wedge off after the bolt is free.
09-02-21, 10:10 PM
#225
Driver School Candidate
I'm hoping I'm OK with just using a pump to get the fluid out thru the fill hole. Too much trouble this time around to get that drain plug out. I stuck a portion of a clothes hanger into a tube so that I could bend it into an "L" so that I can make sure that the end of the tube goes into the bottom of the diff. I didn't get to clean off the drain plug but will have to try some other time.
