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Subaru Gears Product Review and assembly procedure

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First I must begin with saying Todd Triebler from Subarugears.com is a great guy. He has endured a thousand questions from me, and has always been full of answers, and excitement for my project.

A recent vehicle sale, and with support from the wife had me on his site ordering his kit.
I ordered the 3.9 final drive full kit with extended 930 stubs (for Porsche axles and suspension).

The order was placed on August 12th 2014, and the entire kit was on my doorstep by August 18th.
Now, at first I expected that the shipping would take a long time coming from Australia and all. But happily it was very fast.

Now, next I expected that I would receive a box with at best a bunch of parts stuffed in bubble wrap.
Again, this guy went over the top! The parts did come in a plain white cardboard box, but what was inside was much nicer. Probably the nicest shipping package for car parts Ive ever received.

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A fully lockable and foam lined case emblazoned with the subarugears logo
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All of the parts have their own pre-cut slots
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All the parts plus a freebie shifter knob (I wont use it). Each part is looks to be laser etched with the Subaru gear logo as well.
A beautiful packaging job

What is not shown is a boat load of stickers, the pinion depth gauge, and the keys to the case (couldn't find them).
All of the pieces and parts to this kit look and feel to be of very high quality. All of the bearing surfaces are very highly finished. So far I highly recommend this product!

Now Im off to start my assembly process.
Just an FYI everyone, VERY, VERY nice product, and company!
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Brett Proctor

Well-known member
Is there a shift linkage kit for this or do you have to make your own linkage.

Obviously the stock VW shift lever wont work since the Subaru is a 5 speed. How are you going to address that issue. Will the Subaru shift lever work or is there something else out there that works.


New member
Actually the shift linkage connects directly up to the Subaru transmission linkage with no fuss.
see here:

Now no more shoving the shift stick down to try and grab reverse.
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Brett Proctor

Well-known member
So it uses the stock VW shifter??
So is there a gate that goes into the shifter that converts it into a 5 speed pattern.


New member
Yes the VW shifter is used. The shift lock out tabs on the base plate (under the stock shifter) for the VW shifter are cut out. Then the plate is reused.
The shift pattern comes from the shift linkage in the Subaru transmission itself.


New member
So far the transmission build has gone easy peasey.
Only one part has to be pressed on (with no criteria, just bottom it out).
Then since this transmission isn't a bunch of new parts, I reused the pinion shims which set the pinion shaft precisely at zero per the manual specs.
Next is clearancing the case, and setting the backlash, and tooth mesh.
For a modification, this is a very straight forward build.

Now before I assemble the cases I need to look up how to inspect the shift fork pads, and figure out how to tolerance the synchros.

I post pictures of the completed transmission when its assembled, and ready for install.


New member
Just an update to help show the process of this flipped diff kit. Perhaps if someone sees this process they can better understand whats involved.

The case clearancing is by far the biggest pain in the butt of this build.
It takes a careful hand, and hours of grinding.
This is the freshly clearanced right hand case. Since my dremel died I will come back and smooth and radius all the grinds. It was completed with an offset grinder and a 180 grit gator blade.
The burn through in the front corner of this case is caused by it being a TY52 case, and not a TY55,57,or 75.
I have to get the case welded anyway, so Ill have the welder fill this closed.
case clearanced (800x600).jpg

Here is a shot of the diff in place, with the primary shaft laid in place as well. Nothing at this point is permanently in place as I have to mic out the Synchro's but to the eye, they look pretty good.

Total time to get to this point has been 3 hours.
Assembled the new shaft (with pressed in retainer) set pinion depth, and clearanced the case.
flipped diff in place (800x600).jpg

More to come!*thumbs up*
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New member
Just make sure you get a good TY55,57, or 75 transmission to start with. The TY52 I have requires a bit more welding than the other cases.
Also, before you get into the mod, make sure your transmissions internals are good to go. Those parts can be spendy too.


New member
Transmission cases are now finished, and ready for the welder.
I have a local contact for a welder, but Ill have to find him, and get a quote.

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A note to any future customers of Subaru gears products. When you get to this stage insert the gear shafts, input, and center shafts and bolt the transmission together like you would install it. This will keep the entire transmission true after it cools down preventing the cases from warping. DO NOT install the new Ring and pinion. Only the central shafts.


New member
The shift shaft has a hole that needs to be filled in. On the side of the rear case there is a half moon shape that must be closed in. On the upper smaller circle is a bolt hole that must be filled in.
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Also, the big shiny suba-plug on the back must be welded in.

On my main case I have a pin hole I have to get fixed (my tranny had it when I bought it), and Due to it being a TY52 case and not a TY55, 57, or 75 case The clearancing cut through just below the input shaft between some webbing.
Burn through 1 ty52 (800x600).jpgBurn through 2 ty52 (800x600).jpg

The TY52 is thinner in this area than the TY55, 57, or 75 which is why it is recommended to use them instead. Also if you use a TY52 (much cheaper) you will have to source up a replacement TY55, 57, or 75 center diff case like I did.
All small jobs, and maybe an hour or so's worth of welding work.

So far about two full work days worth of work on the case modifications.
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New member
The TY755 turbo transmission has arrived. If anyone wants me to document how this conversion is done, I can. It will take a lot longer to document it, than just do it. Ill wait and see if I get any interest, before I decide.
Its a really easy mod to do, just a few tools, and a grinder/cut off wheel.
So let me know...

For starters:
Here is a comparison between the turbo transmission (TY755) and the non turbo transmission (TY752)


The turbo transmission is on the right, and the non turbo transmission is on the left.

The bolt patterns are the same, only the turbo has more attachment bolt points than the non turbo.
The turbo also has more webbing radially to make it stronger, and the case is thicker.
The turbo transmission also has a hydraulic slave cylinder for the clutch, where the non turbo has a cable operated clutch.


Here you can see the difference between the unmodified turbo transmission and the modified non turbo. The rear case is discarded, and the center case section is the one that's modified.
Its only 8 bolts and the whole rear of the transmission comes off. Just dump out the guts, and keep the case and shift rod.
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GS Guy

New member
The TY755 turbo transmission has arrived. If anyone wants me to document how this conversion is done, I can. It will take a lot longer to document it, than just do it. Ill wait and see if I get any interest, before I decide.
Its a really easy mod to do, just a few tools, and a grinder/cut off wheel.
So let me know...

Yes! I'd definitely be interested in the details of the mods required. I thought there was some welding required too? With the new engine adapter, this trans can be used with the VW engine too - so a viable alternative for anyone wanting a 5-speed but keeping the VW (or T4) engine.


New member
Subarugears makes an adapter for the type 4 engine.
Also, he offers the the two main pieces on eBay here for 1300 USD:
VW Transmission Reversed Ring Pinion for 5 Speed Subaru Trans Fits VW Cars | eBay

Todd, Treibler has a quick run down on his site:

However, I took some photos of my progress: If they are blurry I apologize (it was cold out):

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conversion step (4.5).jpg The last gear on the shaft can be damaged using vise grips etc, you will be tossing it anyway, so its fine to grab at this point to help remove the nut.

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conversion step (12).jpg This part is really simple its only a shaft inside a tube. You cant mess up the gearset here. So dont panic.

conversion step (14).jpg In this picture you can see a large bearing, a washer, and a flat needle bearing that must be transferred to the new pinion shaft. This can be done by hand, or via a press. It take only light pressure to remove and replace them. just take them off, and put them back on in the same order.

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Subaru transmission manual is available
If you would like it, email/pm me.
I didn't get any pictures of my welded up, and modified mid case. But Ill get those done and post it up here.

Next Ill document the transmission clean up, and case clearancing. Again not difficult, you just need to understand how to use a grinder/sander and take your time.
The case clearancing takes the most time. It is done to the side of the case that does not have the starter hole in it.
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New member
Case clearancing:

Now that the Ring and pinion have been installed, it is time to get the case half clearanced. Remember this is done to the case half that DOES NOT have the starter hole in it.

Here are some of the tools you will need:
TY755 case mod tools needed.jpg

The first step is to grind down the webbing flush with the cases inner surface. Grind this down to just about the height of the central bearing boss. The black marker is where I marked the edges of the ring gear mount with the bolt head sticking through.
TY755 case mod marking the second clearance step 1.jpg

Now carefully grind the webbing down far enough for the ring gear mount and bolt heads to clear the webbing.
TY755 case mod cutting the notches step 2.jpg

Here you can see how far down this ring gear mount and the bolts stick out. The bolts must not hit anything while the bearing is sitting evenly in the bearing race.
TY755 case mod ring gear depth profile.jpg

TY755 case mod ring gear depth profile 2.jpg

Here you can see the webbing ground down to allow the center diff and its bolts to spin freely. The shiny surface was made by using a dremel with a wire wheel on it. It burnishes all the edges and smooths them out.
TY755 case mod burnished edges.jpg

Here is another shot. Do your best to smooth out any sharp edges or gouges created by the grinder. You want to prevent any sharp edges. You also want to not grind on any bearing surfaces, or the main bearing boss in the center of the diff case. Once I was finished here, all grinds were smooth with no sharp edges.
TY755 case mod burnished edges 2.jpg

In this photo is the breather vent hole that must be added. The breather vent part number is available on the subaru gears website.
TY755 case mod (9).jpg

A quick video of the ring gear spinning smoothly in the newly clearanced case half.

Finally the gear shafts have been laid back in place and tested for mesh.

Here is a quick couple of shots using my borescope to check the clearances
My Snapshot3.jpgMy Snapshot11.jpg
The shapes are still fairly jagged, and could be smoothed out. I may go back apply my OCD to them later.

Now the next step will be to set the pinion depth, check and adjust the mesh, install the breather vent, and fluid level hole.

Then on to the final assembly...
More to come...
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New member
Output shaft seals reversal:

Once your getting ready to start putting things together, and make everything final, youll need to either replace the seals and put the left in the right side (and vice versa), or if your seals are good, you can swap sides with them.


Use a wrench to remove the keeper
Then use a hammer and a flat tip screw driver to tap the ribbed section counter clockwise until it can be spun by hand.

Clean your parts and now place the left on the right side, and vice versa.

Screw them back into place, until the plate is flush with the surface of the transmission body.
Now assemble the transmission. Youll need to tighten these evenly. So move them a little at a time per side until the central diff spins, but with a small amount of drag on it.


New member
A Note on my previous post:
Try not to use a screw driver and hammer is you can. You can buy the differential side cover tool, or make one. The ribs on the side covers will not tolerate being hit too hard, or too much.

I was using a spanner wrech designed for pluming.
Its not ideal, but it works ok.

Im in the process of making a wrench out of a metal filter housing.

Right now homework for this quarter is taking precedence so when I can Ill get this posted up.

The transmission just recently came back from the shop after getting a really good bath. So things are very clean now and ready to be assembled. Its just waiting for me to get my butt back in the garage now.;)

Pretty soon, it will be time to tear into the motor.*thumbs up*
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Will your transmission use hydraulic clutch actuator or a vw cable? Also do you know if 2008 trans out of non-turbo impreza can be used for this build? Also in your opinion which year and model trans is the best for this conversion? Thanks


New member
Since I will be using the WRX pedal assembly, I will retain the Hydraulic clutch on the transmission.
For information on what transmission to use see here:

Also get ahold of Todd Treibler from subaru gears.com sales@subarugears.com and ask him about more of the specifics. I know you will need an AWD manual 5 speed transmission for this that is 1999 or newer. My TY75 is from a 2000 JDM WRX. My TY52 is from a 1995 Legacy but can be used on non-turbo subaru engines. Since Im using the WRX 2.0 turbo engine I had to get the TY75. You using the single cam engine have more transmission options.
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