MTX swap, MX3 or MX6 trans to use...

[studboy13]

hey, im dooing an ATX to MTX swap, im getting all the parts for a MX3, r the transmissions interchangeable, if sio, what is recommended. ex. gas mileage, speed, accel

[Raven95150]

You can use the tranny from any of these as long as its a V-6 model:

MX-3, MX-6, 626, Ford Probe

These all use the same tranny but the MX-6 and 626 have slightly higher gear ratios.

Most of the other parts will need to be from an MX-3.

[studboy13]

if im getting them for the same price with the same miles, which one would you recommend?

[mx-3_4evr]

well since he said that the mx-6 and 626 have taller gear ratios, I would go for one of those... better gas milage on the freeway for sure. If you are going turbo, that would work also since you wouldn't be able to spin the wheels as easily

[mx3autozam]

Well what do you want to do with the car. race it or just for economy. I would definitly go with the mx3/probe tranny if your a speed freak. If you use the car for daily driving to work or whatever and involves highway driving than go with the mx6/626 trans because you will be at a lower rpm when driving.

MX3/Probe Final drive is 4.39:1
MX6/626 Final drive is 4.11:1

[studboy13]

i think im mostly concerned wit the speed
but whenever i see an mx3 video on youtube or something, people have their tires spinning (no grip) constantly, i thought it might be sort of a fair trade off

[Mooneggs]

that's what I thought too when I put a 626 tranny in my klze... but if I build another klze I'm going mx-3 tranny for sure...

I have just been informed that the 626/mx-6 tranny is identical to the mx-3 except for the final gear (as mx3autozam stated)... so go with a 626 or mx-6 unless you just feel like you need higher rpm in 5th gear.

[mx3autozam]

either tranny you will have plenty of tire spin. The solution for that is some good tires and an lsd. but tire spin is what you get when you got power.

[JoshVK]

how does one get a LSD? who makes? any links?

[studboy13]

so, only the 5th gear is different? anybody have the top speeds of both trannies? has anyone ever swapped 1 for the other, and in that case, what did they notice?

[Nd4SpdSe]

I have just been informed that the 626/mx-6 tranny is identical to the mx-3 except for the final gear

No, not at all. The final drive is the gearing that multiplies your torque, leverage. The Mx-3/Probe and Mx-6/626 tranny's gears themselves are all the same, the final drive actually changes the (final drive) ratio of all the rears. (There is word that the 626 tranny uses a longer 5th gear over the Mx-6 tranny, but I have yet to find information confirming that)

In front-wheel drive, it's a weird concept to understand what final drive is because FWD cars use all-in-one 'transaxle' system, but if you break it down using a rear-wheel drive system of a transmission + drive shaft + rear differential, it's easier to understand.

In explaining this, imagine an Mx-3 and a Mx-6, but say they're rear-wheel drive. They would both actually have the exact same transmission, so all the gears from 1 through 5 (and reverse) would all be the same.

1st: 3.31
2nd: 1.83
3rd: 1.31
4th: 1.03
5th: 0.80

From that point on, this is where it differs. The final drive would be determined in the rear differential in the rear axle. If you ever hear anyone with a RWD car talking about them changing the gearing on the rear end, this is it. This basically changes the the length of all the gears without touching the transmission itself. On a RWD car, a final drive of 4.38:1 would mean that the drive shaft actually turns 4.38 times for every 1 turn of the axles/wheels. For 4.11:1, well, I'm sure you can figure that out. By having a larger number for the final drive, you bring the gears closer together (shorter), so theoretically improving acceleration, but having a lower top speed. If you have a smaller number for the final drive, the gears become longer, sacrificing acceleration for top speed.


Here's a basic break down for a FWD drive system


In red those would be your actual gears, 1st through 5th and reverse.

In green is where your final drive is determined; the small pinion gear and the ring gear around the differential. When it comes to the final drive in FWD cars, for the Mx-3/Probe, the pinion gear turns 4.38 times to make the differential turn once. In the Mx-6/626, it takes less turns, 4.11 turns of the pinion gear to make the differential turn once. A RWD car uses pinion gear & differential ring gear system as well, it just sits external to the tranny, in the rear differential, but function is basically identical FWD or RWD.

Now, in reference to the pinion gear and differential and how it determines the difference between the 4.38 and 4.11 trannys, it affects your LSD options. One of the options is to use the LSD from a MazdaSpeed Protege, but it's ring gear is matched for a 4.11:1 ratio pinion gear, so you'd have use an mx-6/626 tranny with 4:11:1 gears, swap the pinion gear from a 4:11:1 tranny into your Mx-3 tranny (if that's possible), or use the ring gear from the stock Mx-3 (4.38:1) differential and put it on the MSP LSD. There's also the Quaife LSD, it's pricey no doubt, but you need to use the ring year form what ever tranny your using.


As for which one, hard to say. I'm giving the 4.11 gearset a try. I've heard mix opinions on which one to use, I know a ZE Mx-6 driver who used the 4:38 tranny cause he said it was quicker, as well, I know a ZE Probe drivers who's car is apparently quicker with a 4.11 tranny, both guys are low 14 cars with street tires. Alot of people complain that the 4.38 gears are too short. Even though Probes uses the 4.38:1 tranny, they actually put larger tires on it compared to the Mx-6 to get the acceleration they advertised. So it's really hard to say. Reason why I want to try the 4.11, cause I do think they're a bit too short, I think that with slightly longer gears, 1st gear would be more useful, probably a better hole-shot if your dragging, you'd stick in the power band longer too with each gear, also that means less shifting as well as less use of the longer 4th gear (4th in 4.38 is still much longer than 3rd in 4.11). Actually, if I remember right, the Probe driver I talked to says he doesn't usually use 4th when he drags (Mooneggs confirms this). As well, I may miss the quickness of 5th gear. Despite that it revs farily high on the highway, it sits right in the sweetspot for power. However, it almost means with the higher gears that 4th is longer too, so I can downshift to it as a higher speed, and and hold that gear longer.


I hope this clears up all questions about the trannies If anything, it may give you mroe questions, but hopefully you'll have more information to help you out.

[Mooneggs]

thanks for clearing that up mike!

[707-MX3]

A quick question. So what final drive gear ratio would be in the Protege LX, Escort GT & LX-E and Tracer LTS?
4.39 or 4.11
And what are each of these tranny's(the probe, mx-3, mx-6, 626, protege lx, escort gt, escort lx-e & tracer lts),
the G5M-R or the G25M-R.

[707-MX3]

Well I found an answer to most of my question.

Gro Harlem wrote:
FYI for those who are out of the know....the list below details the G-series mazda gear box:

Cars with 4.39 final drive:
-92-96 MX-3 GS with 1.8 V6
-93-97 Ford Probe GT

Cars with 4.11 Final drive:
-90-94 Mazda Protege LX (1.8 dohc)
-95 Protege ES
-93-97 Mazda 626 and MX-6 (both 4cyl and 6cyl
-98-02 Mazda 626 (all models)
-01-03.5 Protege (all with 2.0 engines)
-91-94 Mercury Capri (all) note, these all have a cable operated clutch (which doesn't really matter if ur just taking the gears)
-91-96 Ford Escort GT or LX-E (with 1.8 dohc)
-91-96 Mercury Tracer LTS (with 1.8 dohc)
-97-Present Ford Escort & ZX2 (ALL MODELS, either 2.0 SPI or Zetec...all have a G-series gear box)

I'm still wondering which is g5m-r and which is g25m-r? And if they are all the same strength or if some are stronger than others.

[wytbishop]

I posted a link a while back to a thread in the iMazda.com forum which details the rebuild procedure for the G25M-R tranny with a MazdaSpeed LSD. In that link, reliable people in the know report that the 626 5th gears are in fact taller than the other G series cars.

Yoda on this site has also said that he at one time had taken a 5th gear set from an 86' 323 GTR (Not totally certain there) for a really tall 0.68:1 5th gear ratio but that the plugs fouled because the rpm was too low at cruising speeds.

There are definitly different gear ratios available in addition to different final drive ratios.