How I Changed My Gear Oil
 

I had just driven my car for about 5 minutes, so the engine and tranny were all warmed up. I jacked up the car and blocked the back wheels like so:
http://images.cardomain.com/member_i...319_1_full.jpg

Using a 23mm socket, undo the fill plug to make sure you can put new stuff in.
Fill plug:
http://images.cardomain.com/member_i...319_2_full.jpg

Take off the used gasket and throw it away. Next, position the drain pan under the drain plug, and remember it will come out angled. For the drain plug, you NEED a SOCKET. A combo wrench will NOT work. AutoZone had 23mm sockets (1/2 drive), but Sears and other places skip over 23mm size.

Drain plug:
http://images.cardomain.com/member_i...319_3_full.jpg

Once the gear oil had all drained, I put on a new gasket and tightened it back up. (29-43FT/LB for both drain and fill plugs).

Now, putting the new MT-90 in was not fun by any means. I used clear tubing connected to a small hand pump to SLOWLY pump all three quarts in. Yeah a little spilled, and a little was in the tube, and a little in the bottle still, but the tranny only needs 2.83QT. So once that was all done, I put the fill plug new gasket on and tightened that up. From here on out, just check for leaks, lower the car and clean up. (My driveway has a few rainbow patches now :rolleyes: ).

Overall, I just did a little shifting in my driveway and it was noticably smoother. I can't wait to take it for a real drive. By the way, does anyone know if the gear oil needs to settle or "break in" before I change gears at high RPMs? Thanks, I hope this helps some of you. Any questions, post or PM me.

Nope. At least I didn't bother. Noticed a big improvment especially when shifting up or down into 2nd.

Good Job gcs118
 

Thank you for the write-up on the transmission oil change. I'll be doing it myself shortly and your instructions will be a big help. I also plan to use Red Line oil.

If you don't mind, I have two questions for you. First, what kind of pump did you use and do you think a funnel with a long tube could be used in place of a pump?

Second, according to the FSM manual the car should be level when draining and checking the fluid level. Like you, I'll be raising the front end of my car (I'll be using ramps) and I'm wondering if the transmission will completely drain in this position and if the fluid level can be accurately enough determined? Short of putting the car on a lift, I know there will be some discrepancy so I'm really asking if we'll get enough drain and sufficiently accurate fill level with the front end elevated.

Any comments would be appreciated.

02 DX Millenium Red
MP3 Strut Tower Bar kit
Kartboy Shifter Bushings
AEM Short Ram intake (sometimes)

What kind of gasket is it that you replaced??? I've been looking into doing this myself but have never noticed anyone mention changing a gasket on the fill plug.

It's really just a washer, similar to the one used on the oil drain plug.

Re: Good Job gcs118
 

First off, I'm not so sure a funnel and tube would work. The fill plug is angled downwards at a decent angle. It would seem to me that the oil would just sit in the bottom of the tube and fill up the funnel. What I used had a long piece of clear, vinyl tubing connected to a black oval hand pump, followed by a short tubing piece. It was the perfect size, although I am not sure of any specifications on it, it is an old tool of my father's. I tried many different ways with funnels, but none seemed to work out. Let me know if you have any luck.

Second, about the draining, it's similar to the engine oil. The drain plug is on the very bottom of the transaxle, so a majority will come out, and only a very slight amount will remain (unless you have an ATX then I don't know). I lifted my car just so I could fit underneath, however you could angle it up more, drain it, lower it, let it finish draining (if any is even left), then raise it back up. In my opinion, it drained well enough with the front raised.

Mazda has two gasket sizes, a large and small. Go to your dealer and get the larger ones. As someone else stated, it's simply a crush washer. There are smaller ones they can give you for your oil drain plug, too. My dealer gives me both gaskets for free, but if they charge you it won't be any more than a few cents probably.

I used a funnel with a long tube that I picked up at WalMart.

Worked fine, no issues. Just slow. Have doen it twice so far.

how much is the funnel, also does anyone know if walmart sells mobil1 synthedic gear oil?

When I changed my gear oil ( To Redline Super Light Shock Proof) I used a pump on top of the gallon bottle that had a long spout. I stuck the spout in the fill hole, and kept just pushing the bottle up and down until full. Good write up by the way! :bt:

I can't imagine a plastic funnel is any more than a few bucks, but not sure about the metal ones. Just about all automotive stores carry Mobil 1 products, I haven't been to Wal-Mart in awhile, but just call or drop by.

I've used Mobil1 synthetic tranny oil before and I wasn't very impressed with it. In one of my old RX-7's, it actually made shifting WORSE, and I've heard of other folks having similar problems on other vehicles. :(

Redline MT-90 is a far superior product IMHO. :bt:

Don't bother with Mobil1 gear oil. I tried it first and it did not make much difference. Redline MT90 was much better.

i found mobil1 gear oil for 9 bucks a quart. how much is the redline where is the best place to order it

I picked up 3 quarts of Redline at my local speed shop for less than $8 a piece. I've seen them in catalogs for $7.95 each, too. Seems to be more inexpensive than Mobil 1 and works better from what I hear.