VR Corrado 02S 6-speed swap. Yes, I am doing it!

[Pavlo]

I ve been reading some on this mystery VW 6 speed and is a 02A/02J's cousin. I found one about 400 miles away from me and decided to get it! The bellhousing is a 4 cyl. bolt pattern so it must be change out. For parts I have my buddy's 02A with a peloquins diff in it, he stripped 3rd pretty good. The 02S is quite cool, it really is just like an 02A, but there are several interesting changes. There are plastic oil "guiding" pieces in it, guiding more fluid to the diff. The synchronizer design is changed, and just playing with them you can definitely tell that they grab stronger to the gear then the previous style.
After doing all the clearance tests with new bearings installed, found that the mainshaft clearance is such that no Vw shim will make it right, so had to machine the bearing race itself to achieve the proper 0.20mm preload. The differential swapped right in, meaning 02J and 02A diffs are identical, aside from bolt in/ pop in axle flanges. You do need the 02j-B diff if you gonna buy one specifically for the 6-speed, the o2S has the new style ring gear, 113mm ID, and the 12.25mm bolt holes. I am not buying a new diff because of financial reasons, and instead having my diff machined to accept the new style ring gear and bolts. The factory 02S diff will work for the swap, you'll just have to get some 100mm axle flanges, and install the speedo drive gear on the 02S diff (and it has a spot for it!). This new transmission also uses quite heavy diff preload springs, much tighter then any previous VW trans I've played with. So if you just want good fuel economy, you will still enjoy the gearbox as is.
I am writing on my iPhone, but within next few days I will update everyone with pictures and all the little things I found out about this unicorn transmission. I ve been working on this project for several weeks now and have gathered quite a bit of information, including gear ratios and such. Check in now and again for all the updates.

*Bearings and Seals: Get them for the 02A, same part numbers for bearings, and seals to match the axle flanges you are going to use.

*Ring and pinion is Identical to the CDM, it is a 3.647 final with identical number of teeth to the CDM. The gears themselves are shorter ratio though, giving better acceleration, and a top speed of 181mph with 205/45/16. At 80 MPH on that same tire I should be a hair over 3k rpm, which will build much less heat at cruising speed, and should use much less gas. If I cruise at 85mph-25mpg, at 75mph-28.4mpg, of course the drag at the higher speeds needs to be accounted for as well. From what I gathered these transmissions come with either 3.94 final, or a 3.64.

This is the 5th and 6th, it does use an extra set of needle bearings in the cover for support reasons. Which is great as the two shafts have even more support from separating under load:


The gears and diff in the 02S/0A4 housing:


The two halfs assembled to measure clearances to shim for proper preload:


And made it look pretty haha:


In this last picture you can see the lip where the axle flange goes into, the 02A does not have that. This lip is what holds a new style seal, which is larger in OD and ID. Below it the case is machined for a regular 02A seal, which I've already test fitted with no issues. My only concern is flange clearance, in which case that lip will have to be machined off completely. The reason I am staying with the 02S/0A4 main case is because the bearing are already in it, so less money spent and less work required. You could use the whole 02A and swap all the gears in (I havent inspected that for sure though, so dont take my word for it as of yet).


She is finally finished! Ran into some complications with making the ring gear work on the 02A diff, but its done, ended up TIG welding small stitches in between bolts in 4 sections opposing each other for balancing. Picking on which rod to use was a bit of a challenge as couldn't find out exactly which metal is used for the ring gear. Silicon Bronze rod ended up being the one that I went with after discussing the application with several people. And because VW trans sealer is $80 a tube (LOL), I just used some quality Hylomar to seal the trans. Gonna install it this weekend.

Another complication is the way the shift cables are adjusted, as the MK5 and up VWs use a threaded rod on the cables, vs. a slip and slide on the Rrado, but I may weld the 02A selector ends to the the 02S, that way I'll be able to alter the mechanical advantage of the levers as well, creating a shorter throw. I have till the end of the week to come up with a conclusive decision .

More to follow.

-Pashka

[Pavlo]

And sorry for the spelling, auto-correct can be a hassle, I will edit it soon.

[petethepug]

[dasbeast3.0]

kinda cool but its still single shaft and just as weak as the o2a. to doing something different tho.

[Pavlo]

My Corrado is my daily, I have a BVH for it that I am currently porting and such and going to build an ITB set-up for her. And my syncro cracked, so this is not that much money considering how much gears and hubs are from VW. I dont want to build a crazy fast Corrado, it is beautiful for what it is. For the high horsepower build I have my E30, which isnt nearly as fragile as the Rrado, and to go really fast I have my Ducati SS. I ve already replaced axles multiple times (inner failures), have rebuilt my "race" engine mounts twice, cracked a subframe, rod bearings, need to do the mains as oil temp has been running high, chains..... It is not just a weak transmission lol.
And yet, every time I get in for a drive I have a grin on my face. I know what I want out of it, and this trans will do me just fine.
And the fact that I can make Every M3 driver pissed off in a series of curves makes it even better.

[petethepug]

What diff are you going to use?

[Pavlo]

02A Peloquins, because I already have one and it was free (well, a trade). I am just having it machined to accept the smaller ring gear, and the the holes tapped for arp bolts. Another benefit to the 02A diff is using the factory axle flanges, you can buy the right LSD, or use the original one from the 02S, and use 2.0l/TDI MK4 bolt in flanges that are 100mm. When using the transmission's original, you will need to pull one of the bearings and install a drive gear for the speed sensor, and of course re-shimming the carrier will be required no matter what.

[dasbeast3.0]

My Corrado is my daily, I have a BVH for it that I am currently porting and such and going to build an ITB set-up for her. And my syncro cracked, so this is not that much money considering how much gears and hubs are from VW. I dont want to build a crazy fast Corrado, it is beautiful for what it is. For the high horsepower build I have my E30, which isnt nearly as fragile as the Rrado, and to go really fast I have my Ducati SS. I ve already replaced axles multiple times (inner failures), have rebuilt my "race" engine mounts twice, cracked a subframe, rod bearings, need to do the mains as oil temp has been running high, chains..... It is not just a weak transmission lol.
And yet, every time I get in for a drive I have a grin on my face. I know what I want out of it, and this trans will do me just fine.
And the fact that I can make Every M3 driver pissed off in a series of curves makes it even better.

Def. makes sense. Sounds like u know exactly what you want out of it and no one can argue with that one. gonna keep an eye on this, I like when people actually use their head to make something work.

[SLC4EVER]

Looks like fun.

What is the I.D. and O.D. of the 5th-6th end bearings? The two that go in the the additional end cover. Just curious.

[vitamin C]

pretty sure Inner Diameter and Outer Diameter

[SLC4EVER]

pretty sure Inner Diameter and Outer Diameter

...would be?

I was asking what the actual diameter was, not what I.D. and O.D. stand for.

[vitamin C]

Ha ha ahhhhh yes, it does help to read the whole sentence, yes it does....

[s.l.c.]

...would be?

I was asking what the actual diameter was, not what I.D. and O.D. stand for.

LoL

[petethepug]

Do you have that candy apple in the car yet?

[Pavlo]

Just updated, machine shop took a while with the ring gear. Going in this weekend! I forgot to measure the bearing sizes, but referencing the races to some other parts that I did measure, I would say about 42mm. They are quite healthy, look very similar to the needle bearing supporting the pinion shaft before the 5th section of the 02A.

Since, I've also modified a few suspension angles and attachment points, the car is a demon when it comes to handling now. People say it feels like it has casters in the rear when she turns. With a limited slip she will be one mean lady.

Next project is ITBs on my big valve head and a stand alone, but that will be in a while, still learning TIG welding aluminum.

[Pavlo]

And she is in. The acceleration is much improved, 2mpg extra so far, LSD is by far the best mod for the money. The car is absolutely phenomenal now, do not regret a single penny spent. However it took 10hrs to get everything in and working, including a lot of cutting and welding. Not quite a bolt in lol. I'll mention everything that needed to be done sometime this week.

[petethepug]

Congrat's on the bolt in .. ha ha! How typical for a Corrado. It's amazing how a LSD can make the car something totally different. The six speed and the LSD have got to make that car a blast to drive. Let us know what it does to the top end.

[Pavlo]

Yes, the LSD is a confidence boost, now I am gonna get in trouble with this thing . The car is breaking traction in first as well, even with the diff, a nicer level of mechanical torque for sure. And at 100mph I am still a tad under 3400. Every time I get in the car I am grinning, Corrados have that feature, now its more like the Enzyte guy in those commercials haha.

[TheBurninator]

Odd question you may or may not be able to answer.

Can you use the 02A selector tower in the 02S? The flange for it looks almost identical...

[Pavlo]

Nope, tried it. Forgot why not, but remember that it will not work. If you install all the 02s internals into a 02A it may work though, I decided to keep the 02S main case though. And ts still rocking great! Have about 2k miles on the set-up now. Needs a few extra ponies now...

[RAZZOR]

any updates/news ?
How has it been running and holding up ?

[Deutschbag]

That is one super mario ass transmission.

[crzejkr]

nice 3/8 snapon .. got the same one ... and the new bigger brother 1/2 drive lithium! 450lbs torque yet it dosnt believe in any stuck bolts lol...

question.. if i where to buy complete gear sets from an o2s 6spd i can swap em in a 02j as well or just o2a? i know they are very similar. im throwing an o2j as we speak cus my o2o's diff and 5th gear dont get along with 15psi on my lil old 8v 2.0
so after 2-3 trans its time for an upgrade..
but in the near future as funds permit me id like a o2s in there.
but if i can cheap out by slapping the gears alone in the case i could save hundreds.