Common Manual: Transaxle Installation

Because the overwhelming majority of mid-engine cars  use the Graziano transaxle as used in Audi and Lamborghini cars, and available from RCR/Superlite, this manual will focus on that unit. However, there is a wide range of transaxles that could be used, from Audi to Xtrac. For more details on other transaxles, their benefits and drawbacks, and installation details, check out the transaxle page on the SL-C wiki.

Tools and materials needed

• Transaxle Completion kit, and/or separately-sourced clutch, hardware, dowels, engine-to-transaxle adapter plate, etc.

• Small tapping hammer with a soft head, 180-grit sandpaper, wrenches, sockets, allen wrenches as needed.

• For LS engines: Grinder or Dremel tool able to remove aluminum from LS oil pan.

Estimated time

About 6-8 hours, taking your time, including modifying the oil pan on an LS engine.

Adapter plate installation

If you ordered your kit with a Superlite-manufactured adapter plate for the Graziano and a GM LS-series engine, the first step is to bolt the adapter to the transaxle, as shown in the following pictures.

The preferred method is to start by using two alignment dowels to mount the plate to the transaxle. These can be ordered from any Audi dealer, and are part number 086-351-153-A. You need to order two, and they are around $7 each.

The dowels press-fit into the adapter plate. Use a small tapping hammer if necessary, but be sure they are tapped in straight, and that the edges are not damaged in the process. Take your time, and sand the outside of the dowel if needed.

The transaxle can be aligned without these dowels, but mis-alignment is much more likely without them, so they are cheap insurance. A mis-aligned engine-transmission unit can be very expensive, so don't skimp here.

The picture below shows the lower left alignment dowel inserted in the adapter plate, with a bolt through it.

Note the positions of the dowels in the plate below, and the amount they stick out from the plate. This is important for accurate fit-up. 

The picture below shows an adapter with all the bolts and dowels inserted, ready for it to be attached to the engine.

Once the dowels and bolts are in the plate, attach it to the transaxle. When the plate is bolted to the transaxle, it is ready to accept the engine (with clutch and flywheel attached). Use the Allen-head bolts provided in the Transaxle Completion Kit to attach the plate to the transaxle. Torque them to ??? ft lbs.

Attaching the flywheel

Bolt the Superlite-provided custom flywheel to the crankshaft of the engine using the hardware provided in the Transaxle Completion Kit, and torque to ??? ft lbs.

Attaching the input bearing and clutch

The Graziano-specific pilot bearing or input bearing can now be installed into the flywheel. This is part of the Transaxle completion Kit, or can be sourced from reputable bearing suppliers. It has an OD of 43 mm and an ID of 15 mm. 

Note that unlike many domestic engines, this bearing must be installed in the flywheel, not in the crankshaft. You can carefully tap it into place with a soft hammer, or use a press if you have one with a big enough throat. When installed correctly, the bearing lip should be flush in the hole in the center of the flywheel.

Once the bearing is in the flywheel, bolt the clutch to the flywheel with the hardware provided in the Transaxle Completion Kit. Be sure to align the clutch with the flywheel. Most builders use a clutch alignment tool like this one, as it is cheap insurance against a mis-aligned clutch and flywheel.

Carefully torque them to ??? ft lbs, gradually working up to the final torque, rotating the torque wrench in a circular pattern.

The clutch is a stock Audi or Lamborghini unit capable of holding high power, but stronger clutches are available- see the wiki for details.

Attaching the ring gear

Once the clutch is attached to the flywheel, install the ring gear that is part of the Transaxle Completion Kit (or order the appropriate ring gear from local Audi dealer or online).

There is an indent in the pressure plate and ring gear- use this to align them, bolting them together using the hardware from the Transaxle Completion Kit.

Torque the ring gear to the flywheel to ??? ft lbs.

Joining the engine and transaxle

It’s a good idea to join the engine and transaxle as a unit outside of the car, as it makes it easier to both attach the two assemblies, and also to install them as a unit into the car.

Before you join the engine and transaxle, make sure you have clearance between the engine and transaxle. Because the Graziano originally came out of cars with all-wheel-drive, there is a front-facing output shaft. This commonly interferes with some engines. In order to maintain the transaxle warranty, do not cut off the end of the output shaft. Instead, using a small grinder or Dremel, grind off the area of the block (on an LS engine) or oil pan (on a Ford mod motor) as needed. If you are using a different engine, check it for clearance, and make adjustments as needed.

Here’s a picture of a Ford mod motor showing the modification:

Below is a picture of an LS engine with the required modifications to the block:

Once you have the clearance made in the engine as needed, you are ready to bolt the engine (with flywheel and clutch) to the transaxle. To begin, push the transaxle and engine together, making sure that the two are perfectly aligned. If the clutch was installed correctly using the alignment tool, it should slip on the input shaft of the transaxle.

If there is any resistance, don't force it. Resist the urge to "pull them together" using the bolts. Expensive damage will almost certainly result. It may take a few tries, to get the alignment perfect, but when you do, the two parts will join up correctly.

Once joined, the fasteners provided in the Transaxle Completion Kit can be used to tighten up the assembly. Torque the engine-to-adapter bolts to ??? ft lbs.

Starter

The starter can be installed now, with the provided fasteners in the Transaxle Completion Kit. It's easy- just insert it into the starter pocket on the transaxle, and bolt it up.

Torque the starter bolts to no more than ??? ft lbs.

Axles

Your kit likely came with axles with CV joints already installed. You can install them now with the hardware that came with the axles. Clean the threads of the fasteners of all grease, clean out the holes in the transaxle bells to which the axles bolt, use Blue Loctite on the last 1/2" of the thread ends,and torque to 58 ft lbs, per The Driveshaft Shop.

Reverse light wiring

The Graziano transaxle is equipped with a reverse switch. The connector is easy to find, and is VW part number 1J0 973 702. A pigtail with this connector can be found from the usual sources, including eBay.

InfinityBox Harness:

The Infinitybox harness doesn't have a provision for a reverse light, but one is easy to implement. Select an unused output wire from the rear Mastercell, and wire it through the reverse switch to the backup light(s) you select. If you are using the standard tail lights, just insert a bulb in the inner light opening, and wire the two lights in parallel, You'll need to re-program the powercell output to come on when you want it to (probably when ignition is on), unless the output is already on when you need it powered. Reprogramming Infinitybox powercells is easy, and can be done at your home with an inexpensive programmer from Infinitybox, or by Infinitybox themselves. In any case, you'll need an updated program from Infinitybox, so contact them for more details.

All other harnesses:

The chassis harness has a circuit for the reverse light. There is a connector for the transaxle, and a circuit for the light. Since there are too many possible reverse light scenarios, you will need to connect the wire to the reverse lights you implement.

Starter wiring

The transaxle uses standard VW-family connectors for the starter control circuit. For the main power, use a large ring connector and at least #4 wire.

For the starter control, use the following parts:

1.      Connector 357972771

2.      Wire repair kit 979227E

3.      Wire seal 1J0972743

Using the parts above, terminate the wire from the chassis harness so it plugs into the starter.

These parts should be available from any VW dealer. Thanks to Dan C for this info!

Check the wiki for details on other transaxles.