skip to Main Content
Select Currency:

4AGE to J160-G (1GFE) installation guide

Gearbox adapter kit: 4AGE / 7A to J160-G (1GFE) -866

This kit allows a J160 gearbox to be installed onto a Toyota A-series engine. When using our kit, the gearbox doesn‘t need any dissasembly to be fitted. However, depending on the vehicle you’re installing it into, it‘s likely that the external ribs on the bellhousing will need to be ground down as well as the top of the bellhousing being modified for clearance. For more information on this and other relevant information, we recommend you read the following information thoroughly to make sure you order all the parts you need in one go.


Installation notes

– An impact / rattle gun should not be used to do up any bolts, these can easily cause over-tension and damage the threads of this adapter.
– To avoid mix ups, it’s best to open the individual fastener bags only when they are required.
– The supplied fasteners may differ from what is pictured in the photos.
– Some spare washers are included.


Flywheel options

– All of the original 16 and 20V 4age / 4agze flywheels can be used with this adapter, this includes both of the 4agze models (225 + 230mm).
– The early 16V Bigport engines used a flywheel with a 200mm diameter friction disk, while the later 4age engines used a 212mm. Both of these can be used if the matching clutch is fitted, but the larger 212mm type is suggested. Also some clutch companies quote the 212mm size to be 215mm.


Clutch options

– A 4AGZE flywheel and clutch kit can be directly used as is with this kit, however the thrust bearing that is provided in 4AGZE clutch kit is not compatible with our adapter kit. For those using a smaller diameter 4AGE flywheel, please see below.

– Clutch pressure plate: The pressure plate needs to be the matching type / friction diameter for the flywheel being used. If you’re using a 200mm flywheel, then use a 200mm clutch pressure plate, and the same goes for the 212mm one too.

WARNING: You need to use the the same pressure plate and the same type of friction disk. A pressure plate intended for a disk that uses an organic compound shouldn’t be mixed with a multi-puck or button disk. If unsure, call up the clutch company to confirm compatibility. Better yet, buy your clutch and pressure plate as a kit from one manufacturer.

– Friction disk: See the part numbers in the next section and choose a clutch that suits your needs and driving style.

– Clutch fork, Slave cylinder and Retainer clip: These three parts are OEM parts from the J160 Gearbox and should be reused.

– Clutch carrier + Thrust bearing: A custom thrust bearing carrier is supplied as part of the kit. This is compatible with the original J160 clutch fork and retainer clip but instead uses a different thrust bearing. A compatible bearing is the same type as used on both T50 and W5x model gearboxes. This is supplied and pre-fitted with the purchase of a kit.

Compatible clutch part numbers – 200mm

– Friction disk option 1 – organic: Exedy: TYD126UF
– Friction disk option 2 – 5-button: Exedy: TYD126B5 – needs a pressure plate intended for a button disk.

Compatible clutch part numbers – 212 / 215mm

– Friction disk options: Exedy: TYD034U
– Pressure plate option 1 – Heavy duty: Exedy: TYC549HD – Rating: 490kg clamping force
– Pressure plate option 2 – Extra heavy duty: Exedy: TYC613HD – Rating: 680kg clamping force


Starter-motor compatibility

There are many different starter models that are compatible, but some can only be used on one side of the engine. You can use:
– those originally compatible with a T50 gearbox.

Our Starter-Motor upgrade adapter that uses a Honda Starter.

– some of those that where originally used on the earlier front wheel drive gearboxes.

Of these types above, there are two different variants as shown below. Pictured on the right, is one that features a pinion support as part of the housing. The model on the left doesn’t use a support.

If the starter being used doesn’t have a pinion support and isn’t one of our Honda starter adapters then skip the next section completely as there are no bellhousing modifications required. For everything else see below.


Bellhousing modification (Starter-motor clearance)

To fit your starter, you’ll need to use a die grinder or a hand grinder. There needs to be sufficient clearance. To go about performing the necessary bellhousing modifications, follow the steps below. To make this process significantly easier, it’s best to fit the adapter plate on to the gearbox by itself and then test the starter clearance. It’s easier to fit everything together on a bench than while under your car. Once the modification has been made to the bellhousing, clean up the metal particles and bolt the adapter plate to the engine.

– Slide the adapter plate on to the gearbox bellhousing face. There are two dowels that stick out of the adapter plate that will locate to the holes in this face. Once located, use a soft hammer or a steel hammer with a block of wood to tap the plate until it sits flat against the bellhousing surface. Bolt the adapter to the bellhousing.
– Line up the mounting holes between the Starter and the plate to test fit, then roughly mark where the material needs to be removed.
– Remove the adapter plate and grind into the bellhousing as marked out.
– Bolt the starter to the adapter plate and check for manual clearance for the pinion. If there is interference, then grind more of the belhousing away. Once there’s no interference, you should live test your starter with jumper leads.
– Once the starter has successfully been fitted and tested, proceed to the next section

Option 1: Toyota starter motors with a pinion support: Only the static position is required for the test, if the starter can slide into place and have it’s mounting face be able to sit flat against the adapter plate then then is all that’s required.

Option 2: Starter motor upgrade adapter (Honda starter): When using this option it will only have a clearance issue during the outward movement of the pinion as per it’s activation. Therefore, during the test fit, the starter’s pinion needs to manually activated. This can be done a few ways. Some 4age starters have a rear facing cap that can be removed, while on others, the solenoid can be removed, after which it can be manually pushed out. Once the pinion clears the behousing, hook some jumper cables to the solenoid to check for interference.the only modification required is a small releif cut which can easily be performed with a flapper wheel in a hand grinder. This can be seen in the example pictures below with the removed material outlined in red.


Gearbox / Engine Preparation

– Read our J160 Gearbox conversion guide for information on the necessary modifications needed for body and fuel line clearance.

– Remove the existing starter, gearbox, clutch, flywheel, spigot bearing, dust shield and the engine to bellhousing braces. For help on how to remove the old spigot bearing, read our article on the subject.

– Inside the bellhousing of the J160 gearbox, remove the clip from the thrust bearing / carrier and the clutch fork. Then slide the carrier off, as it isn’t re-used.

– If you’re using one of our shifter relocation kits, then only fit the rear extension on the shifter shaft The housing that comes with this kit is best installed through the hole in the floor later on after the gearbox is fitted into place.


Clutch Thrust-carrier, Thrust-Bearing and Fork

– The original J160 clutch fork and retainer clip are reused. However a thrust bearing is the same as the type used on W5x / T50 gearboxes
– Apply grease to the inside of the supplied thrust carrier filling up the grease trap groove. Once done slide the carrier on to gearbox guide tube.

– The clutch fork is to be pushed onto the carrier, this and the retaning clip must be fitted as per the orientation in the picture below. Here is a demonstration of how the carrier, clip and fork should fit together. The clip has been painted purple for ease of visibility, but is normally a dull black colour.


Adapter and Sandwich plate fitment

The engine block should have two locating dowels fitted into it. If any are missing then they must be replaced.

– The engine dowels must not protrude out more than 12mm from the rear face of the engine block. If they do, then a normal hammer should be used to tap them in to the correct clearance.

– Fit the thin steel dust plate onto the engine block. This plate will locate and fit over the two engine block dowels.

– The main adapter plate is fitted the same way on top of the dust plate. This also locates to the same dowels but is a much tighter fit, use a soft hammer or a steel hammer with a block of wood to tap the plate in until it sits flat against the bellhousing surface. It’s possible that the plate won’t initially sit perfectly flat, but it’llstraighten itself out once everything is assembled.

– Once the two plates are fitted, check the dowels from the engine block. These must not stick out past the surface of the adapter plate at all. If they do, remove both plates and use a hammer to knock the dowels further in. The picture below serves as an example of a correctly fitted dowel that doesn’t protrude.

– Open the “Adapter plate to engine block” fastener pack. These bolts do not use washers. Fit them through the plates and tighten them up into the engine block.

– Fit the four large hex bolts through the holes in the adapter plate to clamp it down. There is one bolt for each corner of the engine block. Each one of these fits into a recess in the adapter plate as pictured above.

– Repeat the process above with the small button head bolts. These are located closer to the middle on the flat lower step of the plate.

– Tighten all six bolts.Installed, they should look like the picture below.


Installation of the spigot bearing extension

Included in the kit is a spigot bearing extension, which replaces the original spigot bearing in the crankshaft end. It needs to be fitted in place without hitting the middle of the bearing. A common method is to use a socket tool that has an outside diameter a little smaller than 28mm. Place the socket over the spigot extension and lightly tap it until the extension bottoms out in the crankshaft recess.


Starter-motor fitment

The Starter motor needs to be fitted before the gearbox is bolted up as the bellhousing will cover the access to the starter bolts. The starter motor has two bolts supplied in their own packet. Use these to tighten the starter into place.

– If using one of our Starter motor upgrade adapters is being installed without a Starter motor bolted to it then ensure that the Starter motor adapter isn’t bolted to the gearbox adapter upside down.


Engine block brace and Sandwich plate to adapter plate

Originally, there are cast iron supports that goes on both sides of a 4A engine when fitted to a T50 gearbox. Using this adapter, only the exhaust side brace can be used and it is suggested to do so.

– Loosely fit the two original bolts through the brace into the engine block.

– Using their matching washers, fit the supplied bolts through the brace, sandwich plate and bolt them into the adapter plate.

WARNING: You must use washers with these bolts or else they will protrude out the other side of the adapter plate. See the picture below.

NOTE: Pictured is the earlier model of adapter plate which has some visible differences such as an additional bolt which is no longer part of the design.

– There is a single short button head bolt that is supplied. This is fitted under the intake on the outer edge of the adapter to hold the dust shield.

– Use the remaining bolts and washers to fasten the bottom of the dust shield to the bellhousing.


Flywheel and Clutch

At this stage, both the flywheel and the complete clutch assembly can be fitted. First, fit the flywheel and do up the bolts finger tight. Replacement bolts are available through our store. It’s never a bad idea to replace old bolts.

Our 4AGE flywheel / ring-gear locking tools can be used to stop the engine from turning while torquing the flywheel bolts. To use this tool, temporarily undo the top two main adapter plate to engine block bolts. Slide the flywheel on and hand tighten its bolts in. Then, fit the tool into place using the supplied bolts but without the spacers, of note a small notch might need to be cut out of to clear one of the locating dowels.

– Tighten the flywheel bolts in several stages up to a final tension of 75Nm / 54 Ft-Lbs. Fit the clutch friction disk and pressure plate in place. Locate the friction disk with an alignment tool before tightening the pressure plate bolts to the correct tension. Once you’ve torqued to spec, remove the temporary bolts and tool to then refit the adapter plate to engine block bolts. The ring gear locking tool can be used to properly tension up both the flywheel and clutch bolts.

– Once the flywheel and clutch is installed, put the adapter plate and dust shield back on, mount and wire up the starter, and test start the engine. This is an essential step.


Gearbox fitment

The gearbox can now be installed into the car. If this is being installed into an AE86 then it won’t be required to temporarily drop the engine crossmember for clearance to fit the gearbox onto the engine / clutch.

If you’re using one of our shifter relocation kits, then only fit the rear extension on the shifter shaft for now. The shifter housing that comes with this kit is best installed through the hole in the floor  after the gearbox is installed.

– Once the gearbox is lined up correctly, the bellhousing will slide over and locate to the adapter plate dowels.
– Once the Bellhousing face is flat against the adapter plate on all surfaces use all the matching washers to fit and tighten the supplied bolts from the “Bellhousing to adapter plate” fastener pack.

WARNING: You must at a minimum use one of the supplied washers for the upper right (intake side) bellhousing to adapter bolt. If the bolt is fitted without the washer it will protrude out the other side of the adapter plate and bottom out against the engine block.

NOTE: Two of the mounting holes in the bellhousing are not used with this adapter, this is to no ill effect