PRODUCT DETAILS
Honda Mainshaft Holder & Thrust Shim Tool - Genuine OEM Transmission Service Tools
Rebuilding a Honda manual transmission and want to do it right, not just bolt it back together and hope? If you've touched anything inside the case, new bearings, gears, synchros, distance collars, or a fresh case itself, you have to re-check your mainshaft thrust clearance, and these are the exact tools Honda's service manual calls for to do it. This page covers both the Mainshaft Holder (07GAJ-PG20110) and the Thrust Shim Tool, Honda's Mainshaft Base (07GAJ-PG20130). They're sold separately, so grab the one you need or both, and the full clearance check uses them together.
Why This Step Isn't Optional
Here's the deal, and it's the part people skip and regret. Your mainshaft needs a specific amount of end play, Honda's spec is 0.004" to 0.007", and it's set by a selectable shim. The catch is that swapping any of the parts in that stack, the cases, bearings, hubs, distance collars, can shift that clearance by 0.002" (0.05mm) or more, which is enough to put you out of spec. Run it too tight or too loose and you're looking at a transmission that whines, feels notchy, binds up, or in the worst case grenades itself down the road. So any time you crack a case open and change parts, you check the mainshaft thrust clearance and dial in the correct shim. These tools are how you do that accurately instead of guessing.
What These Tools Actually Do
Straight out of the Honda manual's mainshaft thrust clearance procedure: you pull the 72mm shim and oil guide plate, build the synchro hubs, distance collars, and ball bearing onto the mainshaft, and install the assembled mainshaft. The holder and base give you a solid, repeatable setup to hold the mainshaft so you can take clean measurements, and paired with your own dial indicator you can read the actual thrust clearance down to the thousandth. From there you run the measurements through Honda's shim selection chart and order the correct 72mm shim. No more eyeballing it, no more hoping the old shim still works after you've changed the internals.
Sold Separately
Both tools are sold individually here, so you can order just what you're missing. For the full thrust clearance procedure you'll generally want both the Mainshaft Holder (07GAJ-PG20110) and the Thrust Shim Tool / Mainshaft Base (07GAJ-PG20130) working together. Heads-up: some Honda manuals also list a Mainshaft Collar (07GAJ-PG20120) as part of the same procedure, so check your specific transmission's service manual to confirm exactly which pieces your job calls for before you order.
What Fits
These are set up for K-series transmissions, but the mainshaft thrust clearance procedure is the same basic idea across most Honda and Acura manual transmissions, and these tools work across the D, B, K, and J series gearboxes. If you're building a Honda manual trans, odds are these are the tools your manual is pointing you to. Always cross-check your specific transmission's service manual for the exact tools and the correct shim.
What You Get
- Genuine Honda Mainshaft Holder (07GAJ-PG20110), sold individually
- Genuine Honda Thrust Shim Tool / Mainshaft Base (07GAJ-PG20130), sold individually
- Used together to check mainshaft thrust clearance and select the correct 72mm shim
- Requires your own dial indicator and measuring tools
- For D, B, K, and J series Honda/Acura manual transmissions
Note: Genuine Honda transmission service tools, the Mainshaft Holder (07GAJ-PG20110) and the Thrust Shim Tool, which Honda calls the Mainshaft Base (07GAJ-PG20130), sold separately. These are the special tools specified in Honda's "Mainshaft Thrust Clearance Adjustment (M/T)" procedure. They hold the assembled mainshaft so you can measure and select the correct 72mm thrust shim, setting the mainshaft thrust clearance to Honda's spec of 0.004" to 0.007". This check is required whenever internal parts (cases, bearings, gears, synchros, distance collars) are replaced, since those changes can move the clearance out of spec, and incorrect clearance can cause noise, notchy shifting, binding, or transmission failure. A dial indicator and standard measuring tools are needed and not included. Designed for K-series transmissions and compatible with most Honda and Acura manual transmissions across the D, B, K, and J series. Some transmissions also call for the Mainshaft Collar (07GAJ-PG20120); confirm the required tools and shim in your specific service manual. Sold individually.