Official Transmission Swap Information (Update 21/05/2010)

[seawulff]

ok, i know i have seen it adressed in a few other threads but i cant find it. atx to mtx swap. THE TPS DEAL. i just swaped a dohc b6 from a 95 obd1 into my 93 sohc b6. i used my old mtx but the motor i got had an atx atatched and i had to use the 95 dohc wire harness and parts. the onlything having an issue of course is the tps. i have an ecu from a 94 mtx dohc b6. everything runs except the tps. i did a ton of reading and i have a mtx tps also on hand. the prob is 1. the throtle bodies are different and my mtx tps wont bolt onto the atx throtle body and 2. from what i have figured out the wireing to the ecu is lacking a wire. my book sais its 2L but i dont know how the pin outs are aranged.

[Ryan]

The ATX TPS is a 4 wire, the MTX is a 3 wire. The difference is the potentiometer in the ATX (because the car needs to know if you push the pedal a bit harder to shift down)

The typical fix is getting the correct TB for the harness. I'm not sure what you mean by they don't interchange...

All B series motors have interchangeable TB's... for the vast majority.

[seawulff]

yeah at this point i think i just need the actual pin out diagram for the mtx. all that i find are automatic pin outs. no manual trans computer pin out diagrams.

[Ryan]

IDK what you're talking about.

Why are you posting in here about TPS anyway? Its not rocket science, just learn to use the manuals.

4 banger TPS: http://www.mx-3.com/manuals/showimg.php ... /Z-034.gif" onclick="window.open(this.href);return false;
V6 TPS: http://www.mx-3.com/manuals/showimg.php ... /Z-042.gif" onclick="window.open(this.href);return false;

Obviously the wire that runs to the TCM doesn't exist on the MTX. (Happens to be the L/W (blue/white trace) wire on both engines)

[seawulff]

riiiiight. so number one, the throttle bodies are NOT the same. completely dif mounting system for the tps and completely difrent set up for turning the internals of the tps. number two. thats not the correct pin out diagram for the manual car. at least i assume. the tcm actualy gets 3 wires if you read that diagram and the black blue wire goes to the ecu just like the other 3 wires. it goes to 2d. now regardles. i fabricated a mount set up for the mtx tps on my trottle body, works well but the problem is it that i dont know what wires to connect. my wire harnes is from an atx so it has the 4 wires for the 4 wire tps however no matter how i plug them in to the 3 wire tps it doesnt work. i think there is a different pin out for the tps on manual transmissions, its either that or the car is actualy supposed to have a 4 wire tps. when i had the 4 wire tps connected the check eng light would turn off but it ran funking, idleing up and down however it did need to be adjusted. does anyone that actualy knows something a obout 1.6l dohc motors with manual trans in mx3s have any comments,

[Ryan]

If you have an ATX harness, just plug in the ATX TPS. it does the same functions. Tells the ECM when its at idle, WOT, or somewhere in the middle. Functionally, the ATX TPS just lets the ECM/TCM know if you press harder, to shift up. MTX TPS just doesn't care where you are in the range.

I just did an MTX swap on a 323, and we didn't touch the harness or ECM, we just jumped the P/N switch and took out the hold light, and it works like it was built that way.

Your idle problem could very likely be caused by something else.

[Daninski]

Your idle problem could very likely be caused by something else.

Yes either the dreaded EGR or Terrorists.

[seawulff]

whats the egr deal. i disconected the piping from the manifold and pluged it. would that be an issue

[Ryan]

Okay, I spent all day playing with axles.

First of all, http://www.mx-3.com/manuals/showimg.php ... _M-003.gif" onclick="window.open(this.href);return false;

strictly speaking MX-3 GS's

-The passenger side, MTX axle is longer by 1 mm
-The driver's side, ATX axle is longer by about 2 cm. This is cause for worry.

But its not all lost.

Every axle can be broken down into three parts.
-The outer joint (tap on the outermost ridge with a hammer, its held in by a retaining ring)
-The inner joint (ATX is held in by a retaining ring under the boot, MTX just falls apart, both assemblies are removed from the shaft by removing the C clip on the end of the axle shaft)
-The axle shaft (this is what decides length)

Outer joints are what most often go. They are the ones that click and crackle in corners.

Today I built a franken-axle, I used the MTX shaft, inner joint, and ATX outer joint.

ATX and MTX inner joints are different design, but fit on the shaft and in the trans the same way.

I also discovered that we cannot use KL ATX halfshafts. They are a smaller diameter on the trans side, believe it or not.

I have KL ATX/MTX and K8 ATX/MTX axles and halfshafts laying around, so I'll be adding my discoveries up eventually.

[Evo_Spec]

i noticed you posted information on the F5M-R but didn't post information on F25M-R.
i assume the F5M-R came on the SOHC's and the F25M-R came on the DOHC's?

you should add things like the input splines and the splines for the....rod for the clutch discs

[mazdags94]

Ryan,

I did some messing around with the axles as well and here's what I found:

- KL MTX intermediate shafts are interchangeable with any V6 MTX tranny (you just need the appropriate bolt pattern or have the ability to modify the bracket to fit)

-KL ATX intermediate shafts will not fit on an MTX (the bearing housing bracket is too big)

- K8 ATX intermediate shaft will NOT fit into a KL or K8 MTX (smaller shaft; smaller spline count)

- Definitely need a new DS CV joint when swapping from ATX to MTX (V6 engines).

Also, there is more information on intermediate shafts in this post here: http://www.mx-3.com/phpBB3/viewtopic.php?f=30&t=74534" onclick="window.open(this.href);return false;

hope this helps

[Ryan]

Sorry, I've neglected this project for a long while.

I did learn the other day that you can put F series engines' transmissions (99 protege), that clutch/PP combination onto B series engines' transmissions. Its quite a bit larger.

If anyone comes up with info, still, please feel free to post it. I don't have any 4 bangers anymore. Just a MX-6 LS, and three GS's.

[dude33694]

"The MTX-75 is said (in a couple different articles I read) to be a lot beefier than the one we have."

I know its an old thread but I had to weigh in here.

I've never had to replace a single trans in the mx-3, two mx-6's, or pgt. Ever.

But I am the proud owner of a 1999 Cougar v6 that had a replacement contour box when I bought it, and i've since replaced it twice. So four trannies.

Theyre alright up to about 140 lb-ft iirc but after that theyre useless. Sometime around 98 (i think) they switched from using forged gears to cast gears and the differentials like to shred. The last replacement lasted 12 hours. I'd avoid them at all costs unless you plan to swap in a Torsen or Quaife (torsen is only 600 bucks!) I WILL say that once you've done that they can be pretty solid. I just wouldn't be too abusive if I were you.

Again, sorry to raise the dead. I just had to put it out there for anyone considering it (although noone really seemed interested in it anyway xD)

[Conrad17]

Awesome this is really explanatory.
so the gearing ratios are the same for all the mazda 4 bangers?
so to bump up gears i cant just swap trannies, damn

[Ryan]

No... you can change it.

I know for sure the Mazda 4 door 1.8 SOHC protege has a lower gears trans.

This thread isn't complete, nor comprehensive, unfortunately.