6A12 TT Gear Box Fabrication Project

[biglipzit]

Hello all,

This is just a documentary for everyone who, like us, has trouble locating a Manual 4wd Gear box for the 6a12 twin turbo engine. Me and my friend in the Caribbean, which has a galant sport GT undertook the project to get the car up and running.
The engine and automatic transmission was not good. We proceeded to get a manual 6a12 TT without much trouble, had the blue tab turbos, and spent 2 months now searching the Carribbean for a Manual 4wd gearbox. No luck so far. We have resorted to getting an evolution 2 manual 4wd gear box and are proceeding to do the fabrications to make it work.

First problem was that the starter is in the wrong position and the gearbox will not bolt on completely. The startermotor slot ends up being directly on the block at the rear bank of cylinders.

http://img236.imageshack.us/img236/1179/6a12auto1ef.jpg
This is a picture of the auto gearbox from the 6a12.


http://img236.imageshack.us/img236/503/evomanual4bo.jpg
This is the 4g63 manual gear box that we have to make work in place of the 6a12 gear box


http://img236.imageshack.us/img236/8975/p10100298gk.jpg
http://img236.imageshack.us/img236/4995/p10100311eo.jpg
Ok this is a picture of the 4g63 evo manual gear box with the 6a12 gear box plate resting ontop. Almost all the holes line up but the area where the starter position should be is clearly visible and being non existant on that gear box. That is the part needing the extensive Fabrication.


http://img236.imageshack.us/img236/9822/p10100274ql.jpg
This is the original auto gear box from the 6a12 with the piece being used already cut out.


http://img206.imageshack.us/img206/2684/p10100283sf1.jpg
This is the piece cut out from the auto tranny. A slice out of the bell housing from the evo gear box will be cut out and this new piece with the starter position and mount bolt holes welded back in place.


http://img206.imageshack.us/img206/1985/p10100303rp.jpg
This is the marking for the cut out on the manual evo gear box. That is the piece that will be cut out and replaced using the starter position piece from the auto tranny bell housing. Note that the lever for the release bearing will have to be repositioned to another part of the gear box since the starter position bulge is directly above it. A new hole would be made at the top of the gear box for the new release bearing lever position and the slave cylinder for the clutch will be fabricated into place.

That is all the progress so far. Hopefully it will be completed tomorrow and I can update this guide for all those who may have trouble locating the rare 6a12TT gear box.

[Sports GT]

Yeah Guys... this is what Biglipzit and I have had to resort to after searching and harassing people for a gearbox for my 6A12TT.. that gearbox is ours and we are the guys working on the car along with a few other friends... two 18 year olds in school doing this stuff for fun with the financing of our parents and our friends who just left school working their first jobs... updates will be posted by Biglipzit and if any ideas please let us know.

[bradc]

looks nice guys. I am most intrigued to see how long it will take to get it all done.

[richy rich]

good work keep us informed :thumbsup:

[biglipzit]

Ok guys, Day 2 of the fabrication. Half way through the day and most of the welding has been completed.


http://img347.imageshack.us/img347/1184/p10100341bs.jpg
As you can see the piece has been cut off the manual gear box and the new slice from the auto tranny with the starter motor mount has been welded in place.


http://img347.imageshack.us/img347/9695/p10100354st.jpg
This is the new hole for the release bearing lever. The small piece of aluminium in the gear box is suppose to be welded in place so that the pivot for the lever can be screwed into it.


http://img340.imageshack.us/img340/3903/p10100371iy.jpg
Not the prettiest thing but it works. That is the job the welded did on the gear box. Maybe i can convince him to grind it down smooth for me lol. The old hole for the lever will be covered with a plate welded over it.


http://img340.imageshack.us/img340/6808/p10100397dy.jpg
The final placement of the backing plate. Everything lines up and all looks well with the job so far. Only the release bearing lever and slave cylinder placement left. Project should be finished later today.

I will update as soon as it is all done.

[biglipzit]

Hey guys so sorry about this extremelly late update. Been really busy working on the car which will be leaving my grage tomorrow for the first time. All up and running except for the rear mount on the gear box and the ride side axle which needs to be sorted out elsewhere.

The gearbox fabrication was completed within a week after my last post in this thread and I still got all the pics to post up for all to see the maddness that the poor gear box had to endure to enjoy 6a12 life...


http://img86.imageshack.us/img86/3074/welds24go.jpg

Well this is a close up of the welds after the gearbox got to my house.



http://img64.imageshack.us/img64/8036/throwoutbearing4fb.jpg

This is what the throwout bearing and lever looks like in its new position since it had to be repositioned.



http://img64.imageshack.us/img64/634/slavecylinder5bm.jpg
http://img64.imageshack.us/img64/5202/slavecylinder20iw.jpg

Ok this looks weird but this was actually the only place to repositon the slave cylinder... The car is driving with it like that now so yeh it ACTUALLY works!!!



http://img64.imageshack.us/img64/5364/flywheelon2zv.jpg

Well the evo flywheel was finally mounted on


http://img75.imageshack.us/img75/5097/gearboxon25id.jpg

Followed by the gearbox



Well to cut a long story short... THAT WAS A COMPLETE DISASTER!!!!!!! The starter motor mount which we cut and welded onto the evo gearbox caused the starter motor to be too far away and not deep enough into the gearbox to reach the flywheel!!!! After much brain storming we figured out we could grind and pry off the ring gear from behind the 6a12 torque converted and press it and weld it onto the back of the evolution flywheel... we did this and balanced it but unfortunately no pictures...

Just as we were feeling incredibly victorious we were horrified to find out that the new and improved evo flywheel does not fit into mr. new and improved gearbox! Just when we though everything is going wrong... My dad came up with a kind of idiotic statement which made alot of sense... I quote "Well guys you already f*cked up the gearbox... Might as well **** it up some more."

And so we did...


http://img75.imageshack.us/img75/7288/grinding2ob.jpg

This is how we made that damn flywheel fit into that gearbox... We ground down the inside of the gearbox all around to allow the flywheel to sit down into it perfectly which less than 1mm of clearance... Totally insane. It didn't take away from the structual integrity of the gearbox since it was an inner wall. Where the gearbox bolts to the engine is actually on the other wall of the gearbox so hopefully this will hold up. The RWD output shaft was touching the flywheel also now... Only after the ring gear was welded onto it ofcourse so we cut a groove down the shaft to allow a tooth of the flywheel to slide down it and let the flywheel drop into the gear box. After marking where it dropped into, we then proceeded to grind out a slot into the output shaft to allow the flywheel to rotate within the gearbox without hitting the shaft... I hope when they say high tension steel they mean high tension steel because this shaft just got seriously weakened...


http://img75.imageshack.us/img75/8210/rearoutputshaft9ds.jpg

Ok so this is what the poor output shaft looked like after we were done with it... You guys are free to voice your opinions about this maddness... IT works so no matter what you say, the proof is there! Well we haven't tried a drag race launch with it yet but lets all try to keep our fingers crossed... You can also see how we thinned the inner walls of the gearbox in that pic.




http://img75.imageshack.us/img75/4827/gearboxon8az.jpg

Well after all the grinding the gearbox was finally put on again.


http://img75.imageshack.us/img75/2981/startermotoron6or.jpg

And there she is with the starter motor bolted on. Tested it out and it engages and cranks beautifully.



http://img86.imageshack.us/img86/5200/flywheelfitment9bo.jpg

Ok one of the more interesting pictures I am posting up. This shows the close fitment of the modified flywheel into the ground down gearbox. Note you can see where the ring gear was pressed on and welded into place in the groove at the rear of the evolution 3 flywheel.



http://img86.imageshack.us/img86/4060/flywheelonshaft9ab.jpg

Final picture that I have for now is a closeup of the flywheel and its fitment into the slot cut into the rwd output shaft... Think it will hold up to any abuse???

Well guys the car drives and rolls and the rwd conversion although difficult was a complete success so far. Further testing needs to be done to test the integrity and strength of the modified evo gearbox but so far it gives no problems starting and the clutch even works fine although it is a little hard... Must be harder to push from that angle I guess.

I am interested to see what you guys think of all of this so please feel free to post in here on all your views.

[marmel31]

You guys are fantastic, what a great attitude to have! If it doesn't work get out the grinder and make that b**ch fit. Well done.:d

[Dream Weaver]

Excellent !

Thanks for taking the time to share your experiences ( ! ) with us.

[Wouter]

Fantastic!!

Well done chaps, and thanks for sharing! :thumbsup:

[WireD]

exellent!

ant with EVO gearbox internals.... you have no problems finding stronger gears for the box and tranny...! :D awesome!

[biglipzit]

Thanks guys... I hope it lasts though. Especially through modifications to the 6a12. The evo gearbox is suppose to be alot stronger and parts should be much easier to find. My main worry is the RWD output shaft...