Change only the fifth gear.

[Epic]

Hi Im sure this has beed said in some manner before, but I have tried to search. So sorry to the ones im gonna piss of

I just droped a DE in my ride, quite the improvement I must say. And I love the response and the 0-60. But I want to be able to cruse without the engine crying for its life. So in other words I dont want a new tranny, I just want to swap out the fifth gear. How should I procede to do this?

[umcamara]

Search for "fifth gear swap". There's much more info than anybody could even try to tell you.
I believe the MX-6 has a tranny with a taller fifth gear.

You should proceed to do this by searching.

[RX8SE3P]

Err pretty sure it doesn't, it has a lower final drive so everything is slightly taller, including 5th gear. IIRC - MX3 FD ratio is 4.388 and the MX6 FD ratio is 4.11. Not a massive difference but 500rpms lower here and there can make a difference to fuel economy.

As for the 5th gear swap, it won't work I'm pretty sure ALL gears from the MX3 and 626/MX6 are the same size. Just the final drive is different and that controls the tallness of each gear.

Think about it from a Mazda technicians viewpoint: why the f*** would you make every bloody gear etc different for these engines that are all so similar? No you'd keep it the same and just change some minor things.

[Nd4SpdSe]

Actually something me and mx3autozam were talking about is that it seems that not only that the Mx-6/626 trannys use a taller final drive, which does make all gears longer, but does indeed have a taller 5th as well. Technically they did change a few minor things; the pinion+differential gears for the final drive, and the primary+secondary gears for a taller 5th gear, which you don't even need to take apart the tranny to change.

Here's info on the swap (will need to register)
http://www.imazda.com/forums/showthread.php?t=2701" onclick="window.open(this.href);return false;


Mazda MX6 or 626 Sourced 5th gear Swap
5th Gear #1
(Primary Shaft gear)
NEW PART NUMBER - G560-17-611C

5th Gear #2
(Secondary Shaft gear)
G514-17-308

[nerd racing]

Actually changing the gears isn't that bad either. I had mine apart this morning actually! You take off the black steel cover on the tail of the transmission, and there they are! Then take an inch and a quarter socket to take off the retaining nuts (after you unstake them of course ) You will now need to take a punch and tap out the pin stock holding the selector fork in place, and slide the gears and synchros right off. I didn't have all the parts I needed to finish my swap so I had to put my ground to nothing 5th gears back in, when I do it for good I'll take some really nice pics and do a step by step how to! It will be for putting G-series 5th gears in an F-series trans, but its the same basic principle. I am using some Zx2 gears in mine because they have super overdrive 5th gear.

Oh and the final drive ratio is constant throughout the whole system, but you change the input RPM's when you shift through the gears, so no a different 5th gear will not change the final drive ratio in the differential ring and pinion, but it will change the input RPM's and the output RPM's, and WILL make a world of a difference if you change the gears with a drastically different 5th gear setup.

[Nd4SpdSe]

so no a different 5th gear will not change the final drive ratio in the differential ring and pinion, but it will change the input RPM's and the output RPM's

I didn't say that the 5th gear was the final drive by no means, I'm saying that on the mx-6/626 trans is that both the final drive AND the 5th gear are different. You can put in the Mx-6 5th gear on an Mx-3/Probe 4.38:1 trans and the 5th gear will be longer that stock, but you use that 5th gear in the 4.11:1 Mx-6/626 trans (that combination is stock), the 4.11:1 final drive makes 5th gear even longer than what it would be in the 4.38:1 trans.

[wytbishop]

It is a well documented mod. Many of the old school guys swapped in the MX6/626 5th gear. I'm sure I even read that Yoda used 5th gear out of an 86(?) 323 which gave him a much taller final drive ratio of 0.86:1 in 5th gear.

It's an easy swap and as Nd4SpdSe said, you don't even have to take the tranny apart to do it. I bet you could even do it with the tranny in the car if you were really industrious.

[se7en]

okay, I am interested in this swap now....If I don't have to pull the tranny out...it will be a cakewalk...


thanks for the inspiration...


7

[nerd racing]

I got mine out without pulling the trans. I had to unbolt the splash shield, a few of the bolts are a pain to get to, but they aren't unrealistically hard to get out. I'm making the trip to get the rest of my gear components Sunday or Monday so I'll have a nice writeup with good pics by then.

[Epic]

Im greatfull for the intel guys. But im guessing my technical english is letting me down a bit here What is the differece between "final drive" and "final gear"? And also, what is it that I need to buy? gears from an mx6 tranny?

[nerd racing]

You will need both gears from the MX6/626, I have also found out that you can use ones from a 98 or newer Escort ZX2.

I did a write up on changing the gears in my F-series transmission, hope it helps:

viewtopic.php?f=30&t=65282" onclick="window.open(this.href);return false;

good luck!

[Yoda]

You will need both gears from the MX6/626, I have also found out that you can use ones from a 98 or newer Escort ZX2.

I did a write up on changing the gears in my F-series transmission, hope it helps:

viewtopic.php?f=30&t=65282" onclick="window.open(this.href);return false;

good luck!

Actually it is only the early '98 ZX2 that has the taller .75 5th gear. All other years have the same .80 ratio and the older Mazda's. The 2.0L protege's have the same .75 5th gear. Back in '98 I swapped a .69 5th gear set from a early gen1 FWD 626 in to my MX-3 along witha tranny the 4:11 final. Last year I imported a couple of the HD wide ratio G series MTX with the 3.41final drive and .68 5th gearset from overseas since they were never used domestically or JDM.

Torn them down to send the gears out for REM treatment and install the beefer post 2/02 production syncros but was put on the back burner when other things came up. Originally purchased because they are more high torque/ hp friendly but with the price of gas lately thinking about putting one back together and throwing it into my ZX2 daily driver which should drop the RPMs from 2900rpm@100kmh down to around 2100rpm.

BTW the F series MTX in the Protege with the ZL/ ZM & FP engines should have a 3.85 final drive a .78 5th gear also though some had a .73 5th instead