I have read the previous discussions on the subject, including "How To's" videos and repair manual, but I still have some doubts due to conflicting opinions.
Car is on level with rear ramps and front stands.
I first opened the filler hole on the right (17 mm spanner) and a few sporadic drops came out.
Then I opened the more central filler hole (10 mm Allen key) and 0.45 litres came out.
Then I opened the drain hole (24 mm spanner) and 1.6 litres came out.
Total oil removed: 2.05 litres.
The car has 30,000 km, and the oil is quite dirty, so I assume it is the original oil. I bought the car a couple of years ago with 25,000 km from a Toyota dealer, and considering the condition of the oil with only 5,000 km travelled, I don't think they changed it. Maybe they just topped it up to the wrong level?
In the repair manual I looked at, which I believe refers to the 5-speed gearbox, it seems that refilling should be done through the central hole, but the bolt with the 17 mm spanner is not even shown.
I'm thinking of filling it with 1.8 litres halfway between the two caps ::)
Stick with the 10mm hole, and be reassured by how much you get in, rather than how much you got out :)
https://www.mr2roc.org/index.php?topic=62272.0
I've followed similar to the above on 6 speeds, and so long as oil is coming out the 10mm hole - the job is done. And it is very easy to overfill, as there isn't much space for oil to flow out the hole until you remove the filler pipe.
I would not consider how much to add by volume. Just add it as per procedure and then see how much you used for reassurance.
Last time I added a little over 2l, but some flowed back out. Give time for it to settle and flow around the box too.
+1
When the volume is at the point it runs out the filler hole. Your done.
https://quotefancy.com/quote/932326/Wayne-W-Dyer-The-measure-of-your-life-will-not-be-in-what-you-accumulate-but-in-what-you
@alexcap This may be of use for future reference.
mr2 Handy reference.pdf
@froggerI read the how to by shnazzle and the hole he indicates for the fill level of the 6-speed gearbox is the same as the one indicated for the 5-speed gearbox in the repair manual I looked at.
I only have the repair manual for the 5-speed gearbox, and the hole that shnazzle indicates for filling the 5-speed gearbox is not even shown in the manual.
So I'm still unsure.
The numbers don't lie.
If I removed 2.05 litres of oil from the gearbox and that gearbox was filled at the factory by Toyota or topped up by the Toyota dealer, I wonder why I should now only put in 1.6 litres of oil.
@Ardent The document is very useful, thank you.
For the six-speed gearbox, it says 2.1 litres, which is very close to the 2.05 litres that drained from the gearbox in two days.
To completely clear up my doubts, I would like to find the repair manual for my car with a six-speed gearbox.
If I proceed with filling it up to the cap with the 10 mm Allen key, I am almost certain that I will only put in 1.6 litres instead of the 2.05 litres that were there before.
Not sure if this image helps or not.
Screenshot_20260109_173423_OneDrive.jpg
If that image comes from a repair manual referring to a 6-speed gearbox, something doesn't make sense because it is the exact same image found in the repair manual for a car with a 5-speed gearbox.
I've been here a while and the references to repair manuals all seem to be from one source. I'm not sure if the original was updated or not to reflect any changes.
That said, you can go on the toyota site and pay a fee to access/download what you need.
With a bit luck you can find the link in here somewhere or hopefully someone will pop along with it.
Quick search gives
https://techinfo.toyota.com/techInfoPortal/appmanager/t3/ti?_nfpb=true&_pageLabel=ti_home_page&SMENC=ISO-8859-1&SMLOCALE=US-EN&SMAUTHREASON=0&SMAGENTNAME=%24SM%24mT%252bGLraBu9CwUVnZg4mEDzB2kysT90hgbwsWgdZzNOc%253d&TARGET=%24SM%24https%3A%2F%2Ftechinfo.toyota.com%2F
A more eu based may exist
@alexcapFrom what I remember that illustration in post #5 is nothing like the gearbox on my 2002 MR2 with a 5 speed box.
Some members will recall the discussions about the port at the top of the gear box, blanked off, used on other cars to connect the speedo drive. That was sometimes suggested, incorrectly as an alternative filler hole.
From my recollection on my 5 speed box the drain plug is obvious, the lowest point of access.
For the filler hole there was a choice of two " openings" on the front vertical face of the box, which one became obvious as the other went nowhere.
Since the hole and the 17 mm bolt is not shown anywhere in the repair manual for the 5-speed gearbox model, I am inclined to believe that this is the right hole for filling and adjusting the level in my 6-speed gearbox.
I also checked the service receipts for all the services carried out on the car, all at Toyota dealerships, and it seems that no one has touched the gearbox oil. I am reasonably confident that the oil level I found in the car was the same as when it left the Toyota factory in 2003.
@ArdentI found a European website (https://www.toyota-tech.eu/) but I don't know if it's the right one/reliable.
@JoessonI do not intend to fill the gearbox through the hole provided for the speedometer.
I am sure that the photo I posted is taken from the workshop manual for the car with a 5-speed gearbox.
Quote from: Ardent on January 9, 2026, 20:01I've been here a while and the references to repair manuals all seem to be from one source. I'm not sure if the original was updated or not to reflect any changes.
That said, you can go on the toyota site and pay a fee to access/download what you need.
With a bit luck you can find the link in here somewhere or hopefully someone will pop along with it.
Thanks Ardent, following your suggestions I went to the European website, created an account, paid to consult the repair manual, and now I can confirm that my intuition was correct and for my 6-speed transmission c65 or c66, the fill and level hole is the one on the right with the bolt that unscrews with a 17mm spanner.
I think someone here will need to add a bit of oil.
I'm not surprised no receipt for a gear oil change. I think they were a filled for life type thing.
Don't think Mr T, (toyota) were expecting these to be running around in 20 years time. :)
The fill plugs for the 5 speed and 6 speed are in the same location. The only difference seems to be the 5 speed used an external hex, and the 6 speed has an internal 10 mm hex. When we change fluid in a 6 speed with LSD, it took just over 2 US quart, but we didn't measure exactly, just filled until the oil dripped out the fill plug. Here is a link to a picture, probably of a 5 speed.
Transmission Fill Plug (https://ibb.co/HLkq01jb)
Quote from: Beachbum957 on January 10, 2026, 11:42The fill plugs for the 5 speed and 6 speed are in the same location.
Transmission Fill Plug (https://ibb.co/HLkq01jb)
You're wrong, unless you know more than Mr. "T," and in that case, I raise my hands and apologize.
In my opinion, anyone who has set the oil level of a 6-speed gearbox like mine using the hole with the 10 mm Allen bolt is driving with 0.4 - 0.45 litres of oil less than required.
@ArdentI found a European website (https://www.toyota-tech.eu/) but I don't know if it's the right one/reliable.
The Toyota Tech website is the right one. You can pay for access hourly and all of their workshop manuals are available to download for personal use. Navigate to the MR2 section and download like crazy until you have the full set. It took a couple of hours when I did it a while ago.
Happy hunting
Quote from: alexcap on January 10, 2026, 15:11You're wrong, unless you know more than Mr. "T," and in that case, I raise my hands and apologize.
It appears you are correct as I found the same fill plug information for the Celica C60 transmission as shown by the right plug in your picture (not the 5 speed plug).
However, it also seems people have been using the same plug as used on the 5 speed for many years with no issues. We have been running over 10 years with our 6 speed filled to the plug used with the 5 speed. Other people fill from the speedo plug and somewhat guess on the quantity, also will no apparent ill effects. Our car is in winter storage, so a spring check will be to check the level at both plugs and see if they are different, and by how much.
Quote from: Beachbum957 on January 11, 2026, 13:09check the level at both plugs and see if they are different, and by how much.
I took my time to do everything properly and measure carefully.
I drained 2.05 litres of oil, letting it drain for a long time.
I started filling from the bolt hole with the 17mm spanner, leaving the 10mm Allen key hole open. After adding about 1.6 litres, oil started to come out of the 10mm Allen key hole, so I closed the cap. I added another 0.45 litres and it started to drip from the 17mm bolt filling hole.
Total oil added: 2.05 litres.
The difference in quantity between the two holes was 0.45 litres.
If the gearbox container is more or less the same between 5-speed and 6-speed, in the 6-speed there are extra gears that take up space, so a higher oil level is needed just to have the same amount of oil as in the 5-speed gearbox.
The 6-speed gearbox probably works fine even with 0.45 litres less oil, but it is definitely better to use the prescribed amount of oil.
I do like a bit of due diligence.
For a new member to be adding useful info for future reference. Well played.
Further research confirms alexcap is right, the 6 speed fill plug is NOT the same as the 5 speed. You can learn stuff everyday. Thanks for finding this!
Thanks to everyone's comments on the forum , I am learning a lots of new things. I am glad if I have done something useful for the community.
We are here to help and love new owners getting hands on.
I filled my C60 transmission, which has a similar plugs. The one with the hex is wrong and I got the wrong information from members on Spyderchat. What ended up happening is having a strange vibration with my transmission that could be felt through the clutch pedal when shifting gears. The vibration may have been enhanced because I'm using polyurethane mounts. It might not be felt with the rubber mounts, but it could probably destroy the transmission overtime with the wrong quantity of fluid.
I come to find out that was the wrong plug after looking at the service manual, which I should've done instead of trusting what you read on the Internet. After filling the fluid in the right hole with the right quantity of fluid, the transmission was working great afterwards. It's good to get information on a forum, but it's always better to double check the manual to verify as you have done.
So the 'how to' on this site is incorrect? I which case it needs to be corrected. I have an MR-S with a five speed box so I'm not up to speed on six speed boxes.
Any assistence with corrected wording (and illustration) would be appreciated, so that I can make the correction.
There was some great teamwork here.
It would be great if you could correct shnazzle's guide "Change Gearbox Oil " in "how's to" because there will probably be also someone with a 5-speed gearbox that runs with more oil than necessary.
I'm not the best person to make corrections or write anything because I don't know much English, but if you need any photos, I still have the car up on the jack stands.
@alexcap Photos with clear markings indicating the correct fill plug would be superb.
I don't think there's an issue with five speed boxes as they don't have the hex key plug.
Also a good idea to get a new set of the aluminum crush washers when doing the job. I had an issue where I reused the washers and developed a tiny leak on the drain plug because of my incompetence of over tightening it to the point where I thought I stripped the threads. Thankfully, it was just the washer that was overly crushed and now I use a torque wrench on those bolts.
A picture showing oil fill plug for C60 (biggest picture I could find.
(https://i.ibb.co/yn0fwS8V/Trans-C60-Fill-Plugs.png) (https://ibb.co/yn0fwS8V)
Diagram from Toyota 6 speed SMT shop manual
(https://i.ibb.co/nN7fVDg8/Trans-C66-Fill-Plug.jpg) (https://ibb.co/nN7fVDg8)
We have been running 2 MR2 with 6 speeds (one C66, and one C65 converted from SMT). Both were filled using the same plug as the 5 speed (now identified as the wrong level plug). One has 20,000 miles on the last fill, and the other has 24,000 miles and neither has any issues. In fact, the C66 was bought used and had a noisy 3rd gear, which has gotten quieter over time.
Quote from: Carolyn on January 13, 2026, 09:40@alexcap
Photos with clear markings indicating the correct fill plug would be superb.
I don't think there's an issue with five speed boxes as they don't have the hex key plug.
Am I misremembering a hex key plug on my 02 5 speed?
I recall having a " choice" but the correct one did become very apparent, but it was some time ago.
Thanks everyone for cooperating on this.
I have modified the 'How To'.
Please have a look and give any changes/input.
https://www.mr2roc.org/index.php?topic=62272.msg725375#msg725375 (https://www.mr2roc.org/index.php?topic=62272.msg725375#msg725375)
@Carolyn My 2p would be at step 3.
Check the filler can be removed. Before draining.
And for the ocd amongst us, the torque settings.
Filler and drain plugs. 39 nm
Speedy updates. Well played C. 8)
I have been curious about the hex plug and what is its purpose. I have been told before that it's called a service plug, but for what I don't know and I have always been curious.
I asked ChatGPT and got a very good answer. Having said that I haven't had any issues with the fill plug on a level surface. I did run into issues with filling from the hex plug where it didn't take the right quantity of fluid. I suppose I will doing it like the method below just because I feel it should be done correctly. It makes me think that when you add fluid into the full plug, some of the transmission fluid fills a cavity which overflows to the other side based on the tilt of the transmission. This is why you cannot fill from the hex plug because the transmission fluid will not pool in the right areas and instead drip out the plug early.
QuoteOne plug is the actual fill port, and the other is a fluid level / inspection plug.
Why Toyota did this
The MR2 Spyder's mid-engine layout means the engine and transaxle sit at an angle, not perfectly level like in many front-engine cars. Because of that:
• Filling from a single hole could overfill or underfill the transmission.
• Toyota added a level-check plug so the correct fluid height can be verified regardless of the car's orientation.
How it works (manual transmission)
• Upper plug → Used to add fluid
• Side/lower plug → Used to check correct fluid level
• When fluid just begins to drip from this plug, the level is correct[/
Quote from: Carolyn on January 13, 2026, 11:59Thanks everyone for cooperating on this.
I have modified the 'How To'.
Please have a look and give any changes/input.
https://www.mr2roc.org/index.php?topic=62272.msg725375#msg725375 (https://www.mr2roc.org/index.php?topic=62272.msg725375#msg725375)
Maybe it would be better to remove the last phrase and the last photo currently in the "how to" because the axial inclination has a greater effect on filling a 6-speed gearbox, which has the filler cap moved to the edge of the car, rather than a 5-speed gearbox, which has a more central cap.
I am adding a photo I took of the 6-speed gearbox if it may be useful.
Excellent. You are a real asset to the club.
Changes made.