upgraded trans internals?

[vabreaker20011]

WTF has that post about???????????????????
hahahahahahahaha!!!!!

[Guest]

i don't think i ever broke a transmission maybe im not trying hard enough

[ROB-80E]

I cryo'd my shafts and gears. *touches wood* No breakage of 4th or 5th yet. I'm running the 0.970 4th and the 0.717 5th, which you'd think have more load on the gear due to the lower ratio. My 4th gear has done many 1/4 mile passes too...as with the rest of my box.

I'd vouch for it.

[therieldeal]

ferdi blew up his cryoed tranny, he tried shot peening this time... so far so good and it was affordable. i think i am going to try shot peening next time.

[vabreaker20011]

"shot peening" never heard of this????

[vabreaker20011]

http://www.metalimprovement.com/shot_peening.php
Nevermind Should look before i post my bust!!!

[CaymenEGT91]

wow, glad i got brought into this as the tranny assassin thanks john!
LOL no seriously tho, my ELX went thru 2 trannys, both diff pins..
and my EGTs original tranny seized @ 168k due to low fluid (i didnt know!)

The next tranny that i got from trailrider098 started showin signs of crappy syncros, so i rebuilt it myself and about 5k later my case cracked.

The next tranny came from TheRielDeal from his 180k+beater, and that one blew the entire rear half of the case out! My current tranny has about 94k on it (8k with me) and is running excellent!

For the record, every tranny ive blown has been in the 150k+ range

[deathtrigga]

lol you got some nice luck with trannys huh? i hope i dont blow my f series when i drop a bp in my dx and turbo it... =/

[pikespeakgtx]

Here is what I've gathered about the weaknesses of FWD and AWD Mazda transmissions from FordLazer, 323.co.uk, and other sources.

#1 The first weak link is the gearbox case. The weakness lies at the end of the two main shafts. The steel races in the bearings that support these shafts slip in the aluminum case when the temperatures is high enough inside the transmission for the case to expand. The aluminum case expands further than the steel race which become loose and slip in place. The bearings bind and the force from the gears climbing each other causes the two shafts to bend opposite directions, the bearing binds and BANG there goes the side of the case. Either under the bellhousing or behind 5th gear.

There are fixes to remedy this and this applies to AWD and FWD but the design varies slightly, but same general idea.

Machine a plate from steel to hold the bearing races.


Remove material from the case on a vertical mill the same thickness as the plate.


Add bracing to reduce case flex.



Another thing is to carefully weld a locating key onto the bearing race and machine a slot in the new machined steel plate to accept the key and keep the races from spinning in place.

#2 The gears are weak themselves. Shot peening will bring the GTX gears on par to the GTR gearbox. Cryo helps too.

#3 The main shafts are too small. I think someone else mentioned PAR makes them but $$.

Torco gearoil and and external tranny cooler will help. Keep temps below 180 degrees if possible.

A couple more pictures



At the end of the day, a serious AWD junkie will switch to the Toyota Celica st205 AWD transmission or one from a Mitsubitchy Evo. Because all of these fixes are band-aids and you're only putting off the inevitable.

[therieldeal]

i dont see those external braces doing a damn thing

i think ferdi is right on track. he has a steel plate on the rear housing as you pictured, and he also reinforced the bellhousing with aluminum plate welded in.

as for the races spinning... the shaft races will spin by hand even with everything cold. heck, they fall out when you disassemble the transmission. the only way you'll get them not to spin is if you actually do something to prevent it.

[FazdaBoy4ever]

I am not a tranny junky and have yet to pull my own apart beyond the 5th gear swap, but wouldn't straight cut gears help a lot? I understand if temperature is the enemy that leading to the destruction it wouldnt help alot, but with the straight cut gears when your pulling through a gear there wont be the lateral force pressing the gears apart.

PLUS the added benefit of the cool straight cut gear whine... of course!

[therieldeal]

there will still be force pushing the gears/shafts apart but the bigger teeth on a straight cut gear can better cope with this.

what it DOES eliminate is some of the thrust forces on the shafts which would help prevent the case ends from blowing out.

[Guest]

that's crazy i want one

[BTR-GT94]

damn this is scaring me into turboing my bp, i feel like everywhere i read about tranny problems with these cars, im trying to build a street car nothing TOO serious just a nice little car, im looking at around 230whp, do you guy think itll be able to handle abuse of daily driving and occasional moderate to hard driving?

I drive my GTX every day. All i did was turn the boost down to 10psi (from 15) for the winter. Granted ur goal is probably about 30whp more than i'm making, but it shouldn't have much of a problem if you don't launch it at every stop light and avoid all wheel hop.





then again. I do have a spare tranny ready at all times...

[Lex]

I think some of us that have rebuilt trannies with new bearings/races/shims don't have the proper tools to properly shim the races aggravating play and this problem.

I strongly believe that heat has a lot to do with the failures as well. I am envisioning a water filled "wrap" for the tranny's case with a pump and heat exchanger for track days and abuse as a simple and innovative way to keep it cool.