joel(PA)

This writeup can also be found at my forum: www.2jzpower.com - a site dedicated to 2JZ enthusiasts / swappers.

I am going to be doing a basic writeup on installing a TH400 using the GM bellhousing method. I have about $3500 into this setup without the cost of the transmission itself. THIS SHOULD NOT BE ATTEMPTED BY A BEGINNER, THIS TAKES A LOT OF WORK, AND SHOULD ONLY BE DONE BY PEOPLE NEEDING AN AUTO TRANS TO HOLD BIG POWER. Big thanks go out to DaveH of BoostWerx for his insight and recommendations throughout this process.

Recommended Tools:
1. Cherry picker (engine hoist)
2. Transmission lift
3. Chassis/Car lift
4. Big hammers

Parts needed:
1. JW Ultrabell for TH400 (ebay, or other performance auto parts site)
2. TH400 transmission
3. Block Adapter Plate (I am using a RMR piece bought from www.boostwerx.com)
4. Flexplate (I am using www.boostwerx.com setup)
5. GM Torque Converter
6. Custom Driveshaft
7. TH400 shifter (I am using a Hurst pistol grip from www.summitracing.com)
8. Trans cooler (I am using a unit w/ fan from www.summitracing.com)

The swap involves:
1. Measure from timing belts to hood latch assembly and write down measurment(this tells us where we need to be when we install the new trans so that the motor is at the same angle.
2. Pull existing trans
3. Attach adapter plate and note where tunnel needs pounded out (10 & 2 oclock positions)
4. Pull motor (or in my case pick up the motor and move it up further in the engine bay to allow clearance to pound out the transmission tunnel.
5. Pound the transmission tunnel for clearance of the larger GM bellhousing
6. Cut off ears on Ultrabell and Test fit (i kept it off transmission for test fitting = much easier)
7. Reset the motor in place
8. Bolt ultrabell to transmission
9. Attach flexplate
10. Attach converter to transmission
11. Bolt trans to adapter plate.
12. Make custom transmission crossmember & bolt up transmission
13. Install TH400 shifter
14. Install shifter cables, trans cooler, etc.

I will follow up with details on most of these steps along with pictures that will try to explain it as best as possible.

joel(PA)

STEP 1:

With the stock transmission still installed, measure off a reference point on the 2jz motor. This makes sure when you go to mount the th400 the motor is still level.

For example, i measured from the back of the timing covers to the hood latch assembly.

joel(PA)

STEP 2:

Pull Stock SC300 Transmission

joel(PA)

STEP 3:

Attach adapter plate and note areas where clearances are a problem.

This picture was taken after I already had pounded out the tunnel. the biggest problem areas are in the 10 oclock and 2 oclock positions.

joel(PA)

STEP 4:

Pull the motor
1. Pull out the 2jz motor, OR do what I did: pull the radiator, pick the motor up and move it forward in the engine bay. I then sat the motor back down on the crossmember and got back under the car to pound out the transmission tunnel.
2. get back under the car

joel(PA)

STEP 5:

Using sledgehammer, pound out the transmission tunnel to accomidate the larger bellhousing. I used a combination of 2lb and 10lb sledges to get the desired dimensions. This is basically a eyeball it and hope for the best type of situation, where it might take 2-3 tries to get the tunnel beat out enough.

From underneath


Drivers side


Passenger side


you will also need to pound out around the shift lever, but that can wait until we go to test fit the entire transmission.

joel(PA)

STEP 6:

Modify the ultrabell using a sawzaw (reciprocating saw) and a dremel with heavy duty cutting wheel. this saves A LOT of hammering in the trans tunnel.





Now, the RED bolts that hold the adapter plate to the motor get in the way slightly with the ultrabell, so it needs trimmed out approx 1/4" for the bell to fit over the bolts.

notice the red bolts


trimmed out to fit around the red bolts

joel(PA)

STEP 7:

Replace the cars motor and prepare to test fit the ultrabell.
1. Securely bolt the adapter plate in place now.
2. Reset the motor to the proper level using a floor jack if your working off the ground (or in my case exhaust lift, because my car is up on a chassis lift).
3. Test fit the ultrabell without the transmission attached to the bellhousing. this will save a lot of heavy lifting.
4. hammer out as needed to get proper clearance, try to leave some wiggle room around the bellhousing.
5. keep test fitting, then hammering, then test fit again. do this until you have good clearance.

joel(PA)

STEP 8:

Bolt the ultrabell to the th400 tranny using the bolts included with the ultrabell.

joel(PA)

STEP 9:

Attach the flexplate to the crank

joel(PA)

STEP 10:

Attach the torque converter to the transmission. (I am waiting on my flexplate adapter, then I can finish this step)

joel(PA)

STEP 11:

Bolt the transmission to the adapter plate.

joel(PA)

STEP 12:

Using the stock auto crossmember / trans mount, create an adapter for the TH400 transmission.

I used a piece of 1/4" thick steel (3.5" wide by around 5" long)


Notice, I had to cut/grind out some of the stock lexus mount to clear my huge transmission pan.






To get the right height I used 4 washers to raise the transmission to match the measurement I took earlier from the timing cover to hood latch.

joel(PA)

STEP 13:

Install your TH400 shifter. I am using a Hurst pistol grip I picked up from www.summitracing.com

First, make a 7x5" aluminum or thin steel plate to cover up the stock hole. Then attach the new plate over the hole securely. I used self-tapping screws.


I then used self tapping screws to attach the shifter to the transmission tunnel. Here are some prelimary shots of the shifter setup.

joel(PA)

STEP 14:

Install the shifter cables, trans cooler, transbrake, etc.