Lightning in a World of Thunder

Shift Select Spindle Upgrade

Last updated: September 9, 1999

Date: Wed, 8 Sep 1999 22:28:18 -0500 (CDT)
From: "Steven N. Burkett" (

Shift Select Spindle Upgrade

One of the most common transmission problems experienced by 3rd gen owners is fifth gear synchronizer failure. The symptom is grinding when shifting into fifth gear. The root cause of the failure is that it is relatively easy to "blow" the shift from second to third, and force the transmission directly into fifth. This is particularly a problem under "spirited driving" conditions, as you may well imagine.

The problem is addressed by TSB 001/94, which applies to VIN's 100001 through 210508. The TSB specifies two new parts:

I don't recommend tearing your transmission down and pre-emptively replacing the gear, but you can install the upgraded spindle trivially while the transmission is out. The new spindle cost just under $50.00, at the time of this writing, from your local Mazda dealer.

The spindle is located on the left side of the extension housing, even with the shift lever. It's held on by two bolts. There is a gasket that is supposed to be replaced, you may want to order that as well, although I reused the old one successfully. It's fairly flimsy plastic, so it may break when you remove it.

While the results weren't spectacular, I could subjectively tell the difference. A relatively inexpensive bit of insurance against a transmission rebuild.


Date: Tue, 8 Feb 2000 21:06:46 -0600 (CST)
From: "Steven N. Burkett" (

> I just got off the phone w/Mazdacomp.  They said they knew of no upgraded
> shift select spring or spindle.  Supposedly there was a TSB on this as
> discussed here
> Mazdacomp said they do not have access to TSBs and they showed only 1 part #

Well, I just pulled the TSB text from Alldata. For some fool reason, Mazda didn't change the part number. They instruct dealers with springs in stock to test them by compressing them. The old will compress under 6.7 kg, the new takes 8.9 (both +/- 0.7 kg). When I upgraded mine, I could tell the difference between the two just by pressing on them.

But there is no visible difference. And yes, the spring and spindle are an assembly.

Sorry for the confusion, I will update the web page. Here's the text from alldata, less the picture of "how to test the springs" (as described above):

Manual Transmission - Grinding In 5TH Gear
Bulletin No.: 001/94
Issued: 1/7/94
Revised: 1/27/94


Applicable Model/s 
1993 RX-7



The revised portion of this bulletin is indicated by an asterisk (*).
Replace the original copy with
this revised bulletin.

1993 RX-7 - Vehicles with a VIN of JM1FD332*PO100001 through

  NOTE: The asterisk (*) in the VIN range can be any number (0 through 9) or "X".

  If grinding occurs when shifting to 5th gear, a 5th gear synchronizer ring, damaged by
  mis-shifting, may be the cause. To correct this concern, the shift select spindle has been
  modified to increase accuracy of the shift pattern.

     Verify complaint.
     Replace the shift select spindle and 5th gear synchronizer ring.
     Inspect related parts for damage. Replace as necessary.


  Part Number                  Description

  R503 17 550                  Shift Select Spindle

  W501 17 725B                 5th Gear Synchronizer

   NOTE: The part number of the spindle has not changed. Parts in your
   facing PDC are new.
   Dealers with spindles existing in inventory should check the spindle
   using the method shown.

   (Applies to vehicles covered under normal warranty)

   Warranty Type:                   A
   Symptom Code:                    82
   Damage Code:                     24
   Part Number Main Cause:          R503 17 550
   Operation Number:                J0312XRX
   Labor Hours:                     4.8 Hrs.


Date: Wed, 09 Feb 2000 07:44:36 -0500
From: David Disney (

I can't quote the TSB as it is at home. However, it basically says that the part changed but the part number did not... so if you have an original shift select spindle ('93 and some '94 cars, apparently) then you will notice that the new part has a stronger spring in it.

There is a VIN number breakdown somwhere on the web that tells you if you originally had the old part number. I lost it, but Wade will probably post it if he reads this thread.

I just did a 5th gear synchro job on my car. Here are the parts I ordered:

Shift Select Spindle

5th Gear Synchro

Front/Rear Trans Seals

Rear Main Engine Seal

There are also a few other transmission parts you should get (snap rings, a lock nut, etc.) that the shop manual says you should replace. I don't have those numbers with me or I'd post them.


Date: Wed, 31 May 2000 17:46:08 -0700
From: "Jimmy Sawyer" (

I had the 5th gear synchro done about 4 1/2 months ago. Well actually I had pretty much refreshed my tranny since the damage suspected was a little bit more extensive. I had a little help since my best friend works at West Covina Lincoln/Mercury/Mazda here in California as a service tech so he had access to SST's and dealer wholesale prices. I had to replace:

So I paid a little over $450 in parts including 8.25% sales tax and only $150 in labor costs charged by my best friend but the only drawback to this was that he had to work on my tranny as a side job, so the downtime was about 3 1/2 weeks but on the other hand I paid close attention to the whole process making sure to replace everything that needed to as well as supervising the whole process. He even steam cleaned the tranny in this cleaning machine at the dealer that heated everything up to about 225 degrees. This resulted in my tranny with a new lease on life performing flawlessly with no misshifts or grindings as of yet.

I currently use NEO synthetics 75-90 HD tranny fluid and everything has been great although if I had more money I would have opted for an ACT clutch setup but instead I went with the new OEM updated clutch disk "D" series.


Date: Sat, 24 Mar 2001 18:36:26 -0500
From: "Alan Cross" (
Subject: RE: (rx7) [3] 5th gear synchro replacement & differental support

I have not done this personally but I stood by watching while Cameron (at Pettit) replaced mine and I remember thinking that it looked like something I could do.

As I recall, he stood the thing on the clutch housing, removed the extension housing (the part containing the shift rods), removed the next plate (manual calls it the bearing housing), then the 5th gear is visible. You have to removed a variety of snap rings, half circle rings, and other stuff whose names I don't know.

The only special tools he used were a gear puller, snap ring pliers, a brass hammer, and a magnet to pick up a small metal ball in a shaft. The 5th/reverse shift fork must come off but the majority of the transmission is not even opened. You don't even have to drain the transmission fluid.

Again, I only watched this being done but it looked like pulling the transmission was harder than getting to the syncro. I wouldn't attempt it without a manual, it only took Cam about 10 minutes to have the syncro ring out.

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