6 Speed transmission dry?

I have a 2001 LS with the 6 speed transmission. It's got 1600 miles on it and I decided to get the metal shavings out of my transmission and differential, and put in some good redline fluids.

Aside from the transmission drain plugs being behind body stiffening panels (what a total pain to get to!!!), I found a potential problem with my car:

I drained the transmission and differential fluids into my usual oil pan and added 2 quarts of Redline MTL to the trannie, and a quart of redline 75W90 to the differential. All was going well until I poured the original oils into a milk jug for disposal. I had two half gallon jugs and I only filled one, with a couple tablespoons for the other one. Now I know that you can't get all the oil out, but I can't believe that there's a quart hiding in there, particularly when the trannie took the whole 2 quarts and the differential took almost the whole quart.

MY transmission has been very good feeling (I didn't have any bad shifting like other 6 speed owners have complained about), and now it's feeling amazing. That redline MTL is good stuff. But given how low the transmission was, I can believe that I'd have had problems before my 30K fluid change and they'd be the expensive kind.

Mazda could save a few dollars by not sharpening all the metal edges under the car.

Well, I changed my oil in my transmission again. The MTL made it shift like butter, but it felt like there was too much transmission vibration and such coming through the shift lever. The transmission never made any bad sounds, but the fact that the Redline MTL is 70W80 instead of Mazda's recommended 75W90 made me worry.

I'm pretty anal about things and tend to fixate on potential problems like that. So I decided to put the Redline MT90 (75W90 synthetic) oil in there instead so I could forget about my transmission and just drive. So Tonight Lucy was back up on stands and I was cutting up my forearms and hands doing another change. (last nights was just a flush ).

MY reaction having tried both MTL and MT90:

First and foremost, both are better feeling than the stock dino juice (but that may be due to the low level of the original). But for silky smooth shifting the MTL wins hands down. The MT-90 feels a bit more like stock, requiring a touch more force to get past the syncros. But the 'whirring' vibration (particularly around 4000 RPM) I felt with the MTL is gone with the MT90, it feels like the stock fluid from a vibration standpoint.

The mazda service manual states that for both the 5 and 6 speed gearboxes, 75W90 GL-4 oil should be used. Given how many people are using MTL (and for how long) in their miata's I'd say it will work fine. But now I don't have to worry about it. There are also warrantee issues, but the warrantee period is so short that it probably won't matter a bit.

Thanks Sheldon for your comparison. Never did put synthetic in our 10AE; it had shifting problems that I improved on, but not enough to keep it. Our '92 Miata has MTL in the gearbox. It resolved all our concerns about shifting with the 5-speed. In particular winter shifting is much, much improved. The dino oil just didn't like the cold. Fine when it warmed up, but I got tired of double-clutching.

Good comparison.