Skip to content

Damond Motorsports Mazdaspeed3 Transmission Motor Mount Install Guide

Looking to plant power to the ground, reduce drivetrain slop, drastically lessen wheel hop, all while adding minimal NVH? Look no further, Damond Motorsports has the answer in the DM Transmission Motor Mount for the Mazdaspeed3. Here is our install guide. 




By installing this Product, you understand that:


The buyer/user assumes all risk as to quality, performance and use of these products and agrees to hold DD2, Inc. DBA Damond Motorsports (“DM”) and its representatives not responsible for any injury, loss, or damage; including any and all incidental or consequential damages arising from the sale, installation, or use of our products.


Many parts are intended for “OFF ROAD ” and “RACING” applications only. It is suggested that State and Federal emission regulation be checked, to see whether or not this product complies with those laws. Read through the instruction guide thoroughly, before attempting this install. Do not install any components while the engine is running or shortly after the car has been running. Give the car some time to cool down. Failure to install this product correctly, or failure to remove/reinstall existing components correctly, could result in poor running conditions, or even component and engine failure, which the sole user of this product is responsible for. The install instructions are intended to guide you on how to install this product properly.  Only an experienced mechanic should perform this install.  In addition, DM, and its representatives reserve the right to modify and or discontinue parts without notice. If you the user/buyer of this product do not agree with the above, contact DM immediately, to discuss a possible return of our product for a full refund minus shipping costs, and other fees.

Tools Needed:

Safe means of lifting and supporting the vehicle: jack and jack stands, wheel ramps, or lift.

Torque Wrench

Socket wrench or breaker bar

19mm socket

17mm socket 

12mm socket

10mm socket

16mm socket

18mm open end wrench

15mm socket x2

Flathead screwdrivers or needle-nose pliers


Components supplied should include(old hardware shown in photo, washers no longer included):


TMM base

TMM bushing carrier

TMM top

16mm bolt x 1

15mm bolts x 2

15mm lock nuts x 2

18mm lock nut x 1

19mm short bolt x 1


Begin by partially assembling the Damond Motorsports TMM first.

Assemble the bushing carrier into the base of the mount, with the extended machined face of the carrier facing the flat side of the TMM base. Clearances are tight, so gently press the carrier into the base by using a soft clean surface, till the holes line up on both sides for the bolts to go through:

Take the supplied 15mm bolts, and nuts, and assemble the base to the carrier. Ensure the bushing carrier is flat in the base, pressed all the way down and not at an angle, and tighten the nuts to 35-40ft/lbs.

Now the mount is partially assembled and able to go into your Mazdaspeed3.

(CAUTION: allow the vehicle to cool down fully before attempting any work)

Begin on the vehicle by removing the battery and ECU covers, and disconnect the positive and negative battery cables(10mm).

Remove the battery from the car, and set it aside. Remove the three 10mm bolts securing the battery tray.

Remove the harness clips from the ECU. Push on the grey connector (indicated with green arrows) and swing the white harness clip lock (indicated by the red arrows), and remove the harness clips from the ECU.

Remove the battery tray and ECU from the vehicle and set aside.

Next if your car is equipped with the factory air box, begin removing the air box. Unclip the top portion of the box, via the 4 metal clips (green circles) and unplug the MAF sensor. Loosen the 10mm hose clamp holding the top of the box to the intake tube (red circle). Pull the top of the air box out of the intake tube, and set it aside.

Remove the air filter, and set it aside. Remove the lower portion of the air box by pulling straight up. It is held in place by rubber grommets.



If you have a short ram, cold air, or custom intake equipped, you may not need to remove it, since there is space around the piping to install the TMM. However, if you wish to remove it for more working space, refer to the manufactures instructions.










Continue by properly supporting the vehicle in the air, and then removing the undertray (if the undertray is not equipped, you may not need to lift the vehicle).


Place a jack underneath the transmission, with a soft material such as rubber or wood, as to not damage the transmission casing, and apply enough lifting pressure to support the engine.

Now it’s time to remove the factory TMM (if you have an aftermarket TMM, refer to the manufactures instructions for removal) Use a 17mm socket and remove the 4nuts securing the battery mount and top portion of the factory TMM(earlier cars have 2 10mm bolts securing the battery mount, remove them, location is the red circles).

Remove the battery mount.










With a 19mm socket, remove the center bolt that attaches the TMM top to the cast base(note: this may cause the transmission/engine to shift as this bolt supports the transmission)

Remove the top TMM piece.


Remove the 17mm nuts and 17mm bolt, and remove the cast TMM base from the transmission.

To aid in installing the DM TMM, unclip the shifter cables from the bracket shown here, and unbolt the 12mm bolts securing bracket from the transmission (note: the bracket or cables do not need to be completely removed, just unbolted to allow some movement when installing the DM TMM). To unclip the cables from the bracket, push in on the tabs (green arrows) with a flat head screwdriver or needle nose pliers, and pull directly up. The cables can remain attached to the shift fork assemblies.  


Install the DM TMM base and carrier that was assembled earlier, using the factory nuts, and the provided short fine thread 19mm bolt. Hand tighten the bolt first, and then the 17mm nuts. Torque the bolt first then the nuts to 50ft/lbs.

Position the top TMM piece as shown and insert the provided long 16mm bolt and washer through the top piece and bushing sleeve. Once the bolt is through, place the remaining washer and lock nut on the bolt. If the transmission is supported via a jack, lower the jack and release the load off the transmission. Using an open end wrench on the locknut, tighten to 70ft/lbs(note: use the open end of a wrench on the nut, as the closed end could get caught in place once the bolt is tightened and the threads of the bolt are fully protruding from the nut)


This is the hardest step, as the top piece may not line up easily. This is due to the transmission shifting upon removing the factory TMM, or having other aftermarket motor mounts that secure the engine from moving much. We recommend playing with the jacking position underneath the transmission, lifting and lowering the transmission, until the hole in the top piece lines up with the bushing sleeve, and the bolt can be inserted. In some cases, removing or unbolting the RMM may be needed to provide the movement for the TMM components to line up.

Remount the shifter cable bracket and clip in the shifter cables. TQ spec for the bolts is 12-16ft/lbs.


Install the battery mount on top of the TMM top and secure the 4 factory 17mm nuts to 40ft/lbs.

Reinstall and reconnect the battery and ECU, as well as intake if removed. Install is reverse of removal.


Lower the vehicle if supported, and start the engine. Go for a short test drive to ensure the mount is installed properly. There may be added NVH after installing the mount, and the NVH should settle down a bit once some miles are on the mount.  


Congrats! You have finished the DM TMM install. We hope you enjoy all our mount has to offer.

Previous article Damond Motorsports Mazdaspeed6 Power Steering Cooler Kit Install Guide
Next article Damond Motorsports Mazdaspeed3 Stage 1 Location 2 Oil Catch Can Kit Install Guide