How-To: 6-Speed Manual Transmission Oil Change

I've looked and looked, seems like there is no thread on this, I figured I'd post up on my experiences from today. It can be a tad tricky, although it is pretty simple.

What you need:
24mm socket or 15/16 socket
Breaker Bar
Socket Extension (4WD Models only)
2 quarts (actually 1.9) of your favorite gear oil. (I used Redline MT-90)
Drain pan
Oil pump
New plug washers (optional)
New corrosion resistant plugs (optional)

A quick note about gear oil. Last time I changed my transmission oil I used Mobil1, it made for a horrible squeaking sound anytime I didn't have the clutch pushed in. I changed to Redline MT-90 and the sounds went away instantly.


See the photos below for the location of the drain and fill plugs. The drain is #1 and the fill is #2. The fill plug is on the left of the transmission case facing outward. These photos were taken with my laying under the truck under the drivers seat.




Step 1:
Break the fill plug lose, do not remove yet. You just want to make sure you can get new oil in before you drain the old stuff. If you have a 4WD you need to use a socket extension to be able to work around the drive shaft. You might be able to make it work with a shallow socket or wrench

Step 2:
Break the drain plug lose, remove it, and quickly remove the fill plug so you get a smooth flow of oil and don't make a mess. I used a large 5lbs protein tub to catch the oil, it worked well.

Step 3:
Once the oil is drained, clean the drain plug magnet and threads on the transmission. Use a new washer and if you get a new corrosion resistant drain plug, now is the time to reinstall it.

Step 4:
This is the tricky part, use a pump to fill the transmission. The one I got did not fit the redline bottles, so I had to use an old gear oil bottle, fill it up with the new stuff and pump from there. The problem I found with the pumps is that they do not get all the oil out of the bottle. I ended with about 8 oz I couldn't get into the transmission, and it started flowing out of the fill hole pretty quick, so I plugged it and just went with it.

I hope this helps.

Update 05-26-2020:
Note about oil choice. I’ve circled back and done some research on this, seems like at some point Toyota clarified the spec for the gear oils. The latest info for the 2nd gens is as follows:

Differentials: 75W-85 GL-5
Manual transmission: 75W-90 GL-4
Transfer case: 75W-90 GL-5

As some point Toyota used to spec GL-4 or 5 for the transmission, this is no longer the case and you should ONLY use GL-4. This would be the redline MT-90. Using GL-5 in the transmission will prematurely wear out the synchros. And using GL-4 in the differentials will prematurely wear out the diffs. The transfer case and differential oils should be the standard GL-5 gear oils that Redline sells.

 

Used this same tranny oil when I had my Jetta and it worked great, I plan to use the same stuff when I do my Tacoma, Thanks for the write up. Where did you find how much oil to put in, when I have done other manual tranny changes I would just fill up until the oil started to flow out the fill plug ( assuming the vehicles is not jacked up slanted of course).

 

That's what I'll use when I do my oil change.

http://www.mastertectools.net/image_atus/31204.jpg

 

Just another note, after about 25k miles, (50k-75k) I changed the transmission and rear differential, both looked clean and newish, however the magnets were loaded with debris.

I found the amounts in the Owners Manual. These are the volumes for 6-speed, V6, TRD Off-Road, not sure about other models:

Front Differential: 1.6qt
Transfer Case: 1.1qt
Transmission: 1.9qt
Rear Differential: 3qt

Hmm, that may work better than what I used, I may try that next time.

 

Why do you guys not use the redline mtl.
http://www.redlineoil.com/product.aspx?pid=45&pcid=7

 

They weight on MTL is 70-80, the manual calls for 75-90 which is what MT-90 is.

 

Just curious as to why you are changing manual transmission fluid at 25K miles? What interval does the manual call for?. Also was wondering if the manual calls for synthetic gear oil in the transmission. Certain manual transmissions have been known to have a negative reaction to synthetic gear oil. Not condemning. Just asking.

 

the Mobil 1 gear oil is GL5 rated which could damage the sync rings

Although the FSM says either Gl4 or Gl5, better stick to GL4

 

I changed it the first time at 50k and did not do research, just grabbed the Mobil1 because I use Mobil1 engine oil. As I mentioned in the post, I had some serious gear chirp coming from the transmission after that, so I wanted to change it out ASAP. The redline solved the chirp problem.

 

My SR5 V6 6-speed 4x4 with Mech LSD rear is the same with the exception of LSD additive. I chose RP

$30 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 for the Transmission/Transfer Case. Shifts smooth, no grind in third. No hesitation switching from 2wd to 4hi/lo and back. Recommended change is every 30k same as everything else that has gear oil. I also used Valvoline DuraBlend 80W-90 for the Diffs. And added 2oz of LSD additive to the rear since Durablend contains 3%, Toyota recommends 4%. No chirping whatsoever.

BTW nice write up tamer pretty much the same for me when changing it. Hopefully a mod will sticky this.

 

Thanks, I'm amazed TW has gone this long without an MT write up. In looking for it I found a million threads asking for one, but some how no write up.

Good info. I think I will change again at 100k just to have a solid milestone for all my service. I'll probably do the transfer case and front diff then as well since they get less use. I'll throw in new spark plugs, air filter and coolant as well.

 

Just an update, I've towed 1000 miles from Michigan to Denver and had no issues so far, fingers crossed that stays for awhile. Although my exhaust is louder, I feel like I must have rusted through a hole in the muffler or somewhere in the system.

 

Whats the torque spec for the drain and fill plug?

 

tackled this project today. Kind of a PITA without a transfer pump.

I rigged my bottle of oil with a short length of rubber tubing coming off the top nipple (the lucas oil bottles have a little spout on top). Then squeezed it in the tranny through the tubing. Could only squeeze like a third of a bottle before I'd have to top of the bottle and do it again.

 

Thanks for the great write up. I'll be laying on the cold ground sometime around Thanksgiving doing this, but I'll feel a whole lot better afterwards. I bought two quarts of Royal Purple after hemming about MT-90, but I ordered two bottles of Redline off eBay after thinking twice. I'll return the RP to AutoZone. The MT-90 was $31 shipped.

 

Had my transmission oil changed the other day with Lucal Oil Synthetic

$30 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90. While the engine is still cold, I get a grinding noise when shifting into third. As soon as the engine heats up, it dissapears.

People think I'm crazy. I'm going to revisit the transmission shop this weekend and see what he has to say.

Wishing I had just bought Redline and done it myself right about now...

 

That sounds like your gear oil is too thick for what you want it to do...or at least too thick at cold temperatures, if it goes away once the truck is warmed up. If I were you I'd double clutch into 3rd until you're up to temperature. My Subaru would barely shift when it was cold, but it was fine in warmer climates.

Does Toyota make anything similar to Honda/Acura/GM Synchromesh? I remember back in my Honda days that stuff was magic fluid. I ran MT-90 in my old Xtracab hoping it'd get rid of the occasional second gear grind, but I wasn't that lucky. I think I was expecting too much from the fluid.

 

Possibly, because the old stuff ran fine in negative temperatures. I worry that the guy won't do anything about it and I'll be out the $100 it costed (I got some other things looked at too but still). Hopefully the synchronizer ring thing people have talked about in other threads is in tact because I definately can not afford to have the transmission pulled out and taken apart at this time.

People seem to praise the Redline on here so it may be my best bet before determining if it's something more serious.

 

Nice write up.

A few thoughts after having changed my 2006 6-speed many, many times with Redline MT-90 and having hundreds of thousands of miles on MT-90 in this truck.

Redline MT-90 is great oil and runs smooth in this transmission.

I would NOT jack up the drivers side to get more oil in. Just add until it drains out the fill plug. Mine takes close to the specified 1.9 qts. Mine was overfilled once when it was newish (dealer) and you can smell the gear oil through your shifter boot until you drain it back to correct level.

Manual transmission drain and fill plugs torque spec is 27 ft-lbf.

Redline MT-90 is good in all temperatures in my 6-speed, I have had it down to -29 F without issue. Shifting is stiff at such temperatures but no gear grinding.

The Redline MT-90 is done at 30k miles, change it. The shifting starts to get notchy and unsmooth by 40k miles. A change brought mine back to normal the couple of times I went beyond 30k. I actually usually change it around 25k miles.

 

Holy cow am I overdue (77K factory oil)! I don't get the 3rd gear grind that others have mentioned but I do get a grind going into 5th at higher rpm's. I've gotta do the diff as well. It looks as if I'm going to keep this truck another couple of years at least and I have no issue spending the money for preventive maintence. Well I'm off to change the oil now and grease the u-joints.