PERFORMANCE TH400 RACING TRANSMISSION (Auto).. supports up to 1000HP

GM TH400 Performance Racing Transmission

PERFORMANCE TH400 RACING TRANSMISSION (Auto).. supports up to 1000HP

Our Performance Hydramatic 400 Racing Transmission (Auto) is a mega-performance transmission. It's rated at 1000 RWHP...

Price : $ 3,500.00 Add to cart


This Transmission has a Core Charge
 Shipped only to Commercial/Business Locations


The PerformaBuilt Hydramatic 400 Racing Transmission is a mega-performance transmission capable of 1000 RWHP. This model is an auto/stick trim for the dual purpose vehicle.

Its features include the following components and modifications (nothing but the best):

We start by cleaning the case in our hot cleaner. Then the case is heated to 250 degrees to remove all water residue. It is then checked carefully for any cracks or distortion and, while cooling, is finished with a high gloss aluminum/gray sealant and allowed to finish cooling. This provides a hard durable finish that is oil and stain resistant for you show guys.

We then inspect the rear planetaries carefully, install the heavy duty roller clutch and cage, and install the assembly into the case. Then the heavy duty low reverse band is installed and band clearance checked and set.

The center support is then inspected, resealed and installed into the case. The support bolt is torqued to spec, and the rear end-play tested and adjusted as necessary. Next, the Raybestos Performance/Heavy Duty friction plates are installed, followed by the new intermediate overrun braking clutches.

The direct clutch drum is replaced with the 4L80E direct drum and 34 element sprag and race assembly sealed and installed. Raybestos Performance/Heavy Duty friction and steel plates are installed with the clearance set. The assembly is installed into the case and the drum is static air tested for proper operation.

The forward clutch drum is assembled, heavy duty friction plates installed, and the front pump assembly tested. Special modifications are made to nearly double holding power in this drum.

The pump is carefully inspected, checked for straightness, and a new bushing installed. It is then assembled and installed in the case with the boost valve.

We disassemble the valve body and check all valves for proper motion. We then install the full manual or auto/stick setup, per customer preference, and install a performance filter. A new adjustable modulator is also installed at this time and the transmission is dyno’d for proper operations and line pressure.

The PerformaBuilt Performance Hydramatic 400 Racing Transmission will handle whatever you can dish out and will perform to and beyond your expectations.


Additional information


Please note our Warranty page. This transmission comes with a 1 Year Warranty.


This option provides you a 2 Year Warranty on your PerformaBuilt transmission for an additional $200.


If you purchase a torque converter from us you will automatically get the 2 Year Warranty Upgrade.


This transmission will support up to 1000 RWHP.


Due to the scarcity of cores available for this transmission, a $500 core charge will be added at checkout.


Due to the weight of this transmission it has to be delivered to a commercial or business location with a forklift or loading dock.


All units are available in either 2wd or 4X4. If you have a special application requiring a special adapter or output shaft, please contact us and we will be happy to provide it and quote a price for your special application.


If you have any questions feel free to call 1-888-744-6542, or email us at

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