Changing out the fifth gear to lower gear ratio..

ddogg777

Member
:
2002 Yellow P5
Does anyone know what is involved in changing out the 5th gear in the tranny to lower the final drive ratio? I do a lot of cruising at 70ph all the time and would like to lower my RPMs from 3400 to about 2800-3000. I will be taking apart the tranny and need some info if this can be done. I have no idea where I would get a new gearset from...

gear: ratio (final ratio)
1st: 3.307 (13.575)
2nd: 1.842 (7.561)
3rd: 1.310 (5.378)
4th: 0.970 (3.982)
5th: 0.755 (3.099)
Reverse: 3.166
Final Drive: 4.105
 
i seem to recall something about a 626 or probe or something 5th gear that someone installed. try searching around. its all too distant in my memory to give you move details, sorry.
 
With a final drive, if you swap it out for more acceleration, your top end will be lower. If you put in a lower gear, it will increase the top end, but slow you through the gears.
 
I want lower gears so my revs at 70mph will be less than the current 3400. I will be turbocharging so gears 1-4 will be my power. But, I don't know if I can just swap out one gearset, probably not....anyone?
 
I've wanted to this as well. . .interested, very interested, but we would need to find something with a lower number. . .don't know if anyone has something. Maybe SR can get a "custom" set built.

I'm going to be tearing into my tranny soon (LSD), that would be the perfect time.
 
ok, I would think that it would be perfectly fine that it lowers the geear ratio all the way across and almost decrease the top end power cause if you are doing this I assume you are planning on other mods and most things like header, cams and the such move the power band up right? So this would actually counteract that? and so with mods and this gear ratio change you should have more power across the band? or at least not loose too much low end.
 
t3ase said:
hes gonna do a msp protuge too mp3 swab cuz he dun likie th revz, kplzthx!

What the hell? The MP3 tranny is the same tranny in all over third gen Protege's, including the MSP. Yes, the MSP has some beefier pieces for specific parts plus the LSD, but other than that it is the same.

The gear ratios are the same...

As for changing out just fifth gear, you'd have to a have tranny shop do it. You have to remove the gear from the shaft and get a new put on. However, where to source the gear ratio you want is a whole nother question. I have no idea if any of the gears out of other Mazda tranny's will fit the shaft.

And changing for the 4.30 final drive will lower your top speed, effectively raising the rpm you are at currently in any given speed. The SWC cars run that final gear ratio, along with other sizes for 3, 4 and 5 I think.
 
that'd be a great idea to change the 5th gear to a longer one - when your racing you'd very rarely get from 4th to 5th i'd think...depends on the racing ofcourse....

but when you take the gears out - check to see if there is the possibility of squeezing in 6 gears ;)
 
Looks like I (and little beavis) will be on my own on this one unless someone who knows stumbles across this thread.....
 
ddogg777 said:
Looks like I (and little beavis) will be on my own on this one unless someone who knows stumbles across this thread.....

Hmmm, if memory serves me right (and it seldom does anymore) I think the G-series transmissions had similar sized gears, but some had different ratios.

From what I can see there isn't anything that would be a taller gear (or a better ratio) than what is in there now. G-25 is 0.795:1, not gonna help.

I'm trying to remember...GRM did a refesh on their "Boneyard Brigade" article. Basically its a bunch of hop-up ideas using junk-yard parts. They mentioned things about the Mazda tranny's, but I can't remember off the top of my head what all they said.
 
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