Unfortunately, my transmission finally bit the dust about a week ago. Last week, at 2168 miles, I did an oil & filter change and then took the car for a short test drive. That rotary was humming nicely until I tried to shift into 5th gear. It was a no-go. I tried a couple times more and still a no-go. I pulled off the road and tried shifting into both 5th and reverse and still no-go. Turned the engine off and tried shifting in 5th/reverse and still no luck. At least the car was still drivable using 1st thru 4th gears. I pulled the shift lever to check the bushings and they were still intact. The lower wave washer was split in one spot, but was still intact. So, the car is somewhat drivable, but no 5th or reverse gears making it kind of tough backing out of a parking spot.

Earlier this year, I went for a beer run to my local brewery. When I started out from a stop light, I wasn't able to shift into either 3th or 4th gears. This happened a couple times during my drive and then everything went back to normal. The transmission was shifting fine until last week. Looks like I got a transmission swap in my future. So IDK, I'm betting that either my 5th/reverse clutch hub, synchro or shift fork had broken. It's interesting that both the 1st/2nd and 3rd/4th shift forks are steel, but the 5th/reverse shift fork is aluminum. WTF was Mazda thinking when they did this?

Here is the long boring history on my transmissions. I'm the original owner of this car. My '90 GXL has about 370k miles on the chassis. I was running the original transmission until May 2015. It had about 309k miles when I replaced it. It got stuck in 5th gear while driving to work one morning. Actually, I posted about that last June 2020. (https://www.rx7club.com/2nd-generati...verse-1145168/). I'll copy and paste here for your reading pleasure.

From my old post dated June 2020:

"Back in May 2014, I was driving my S5 NA with MT to work one sunny Wednesday morning. I stop at a stop sign at a not very busy suburban intersection. Shift from 5th to 1st and let off the clutch and the car dies. I restart and try starting off again and the dies again. I immediately realized that my MT was stuck in 5th gear. So, I had it towed to a nearby parking area until that weekend. I thought that one of the shims in the shift lever broke off and partially jammed my shift lever. This happened to me once or twice before. Well, unfortunately it wasn't the shift lever. It must have been either the shift rod or fork, or it may have been something more serious like a clutch hub or synchro. It was my original transmission with nearly 309k miles. I had a spare used transmission with supposedly 190k miles, so I just swapped it out. Threw the old transmission out. Was tempted to tear it apart to find the problem, but I just had surgery and was in no mood."

"Apparently, this is a common problem on NA transmissions. Problems with either the 5th/reverse shift fork, the 5th/reverse clutch hub or the synchros are common. Hopefully, you'll get your RX7 back on the road again soon. If not, than I'd seriously consider trying to pickup a used transmission from a local junk yard or Ebay. Repair your existing transmission and hold on to it. You might need it someday. These transmissions are 30+ years old and some parts are no longer available."

So, back in May 2015 I replaced my original transmission with a used one that I bought from a Penn State engineering student. He had an S5 NA that he was upgrading to a turbo. I actually took a drive up to his parent's house in Westminster, MD to meet with him and pickup the transmission. I remember he was asking a lot of money, but I negotiated with him to get it at reasonable price. So, I decided to buy it and keep it as a spare part. It came out of a '91 RX7 and supposedly had about 190k miles on it according to the guy's father. This is the transmission that's currently in my car. As of now, this transmission has about 251k miles on it. I put about 61k miles on it since May 2015 and it supposedly had 190k miles on it when I bought it. So, as of now 61k + 190k miles = 251k miles. This transmission finally decided to bite the dust.

Now, the story becomes more interesting. Sometime back in the late '90's, I was visiting with family for Christmas in the Chicagoland area. There was a guy that lived in the St. Louis area that had a used S5 NA transmission for sale. I then took a drive from the Chicago area to St. Louis to pick it up and then drove back home to northern VA. My plan was to eventually rebuild it and swap it out with my original transmission. So, it was sitting in my storage area until I decided to pull it out sometime in early 2001.

I tore down this transmission in early 2001. This was my first S5 transmission rebuild. I replaced all the bearings, synchros and what ever else needed replacement. I replaced the original 5th gear set (0.697) with a GTUs 5th gear set (0.756) for a performance boost. At the time, I was considering using an '86 5th gear set (0.711), but opted for the GTUs gear set. So, basically I cleaned and inspected all the parts and replaced all the wear parts such as bearings and synchros. All the replacement parts I bought from Ray Crowe at Malloy Mazda. Apparently, this used transmission was rebuilt once before as I saw from the red RTV that was used to seal the case. Also, the dynamic damper on the output shaft had hammer dings on it as sometimes it's a PITA to remove. Overall, it seemed to be in decent shape at time of tear down.

I swapped out my original transmission with this newly rebuilt transmission in July 2001. The car had 200k miles when I did the swap. This transmission performed amazing well except for a mild vibration at high speeds. I mean like 70-80 mph or higher. I thought it was probably due to the dynamic damper that had been dinged up. So, I removed this transmission with about 45k miles on it in October 2001 and reinstalled my original. I had bought a new dynamic damper from Ray Crowe. I haven't had a chance to replace this damper and actually it's still sitting in its original box next to me as I'm typing this.

Actually, I think the problem was my driveshaft as I replaced the driveshaft when I reinstalled the original transmission. So, I was planning on reinstalling this newly rebuilt transmission but several months later in February 2002 my original engine bit the dust at about 211k miles. It was the rear rotor seal that went out. After sitting 5-months with a blown engine, my main focus was to get the car running again and back on the road. The transmission was the least of my worries. I replaced my engine with a Mazda manufactured engine that I bought from Ray Crowe at Malloy Mazda. My car was running again and back on the road in August 2002.

Ok, so fast forward 20 years. This transmission has been sitting covered with plastic in a climate controlled storage area. My upcoming job is to reinstall this transmission. I searched the web for other options, but transmissions are hard to come by these days. So, I'm glad that I held on to this one. I hope it's still operational? It's been sitting a long time.

After my engine replacement in 2002, I've upgraded my S5 open rear end with an S4 clutch-type LSD. I also installed the GTUs 4.300 ring & pinion set that I bought from Malloy. It will be interesting to see how this transmission with GTUs 5th gear performs with the GTUs 4.300 ring & pinion.

So, right now I'm awaiting parts for this transmission swap. I had a used spare N350 flywheel that I took to a machine shop earlier this week for bead blasting and resurfacing. It wasn't covered and had some surface rust on it. There were a couple machine shops near me that I've used before that have closed down. I don't know if it's due to Covid or what? I took it to a well established machine shop in the area that has been around since 1957. The machinist said that he probably took 0.010-0.015 inch off the surface. Other cars that I've worked on in the past had removal limit stamped on the flywheel, but apparently Mazda doesn't do that. I bought an Exedy clutch kit (p/n 10038) that I recently received. I'm still awaiting delivery on some other parts that I ordered from Tasca. My rear stationary gear seal looks like it has been leaking so I'm planning on replacing both the seal and o-ring. I got new a TO with my Exedy clutch kit, but decided to go with the one recommended by Pineapple Racing (https://www.pineappleracing.com/heav...non-turbo.aspx). So, I ordered this TO bearing from Tasca. Anybody ever use one of these TO bearings? Is it any better than the stock bearing? So, it looks like I've got a transmission swap in my near future.

 

Uhh to answer your first question. Yes every single original owner of a turbo 2 rx7 has used that TO bearing.

 

DR_Knight, you are absolutely correct. My question was, although not clearly stated, is there any advantage to using that bearing for an NA application. Pineapple Racing states: "This is the Heavy Duty throwout bearing originally used in the 87 TurboII, but works for all RX-7 applications prior to 1992, both turbo and non-turbo. This thing is REALLY heavy duty and worth the extra cost!" I was wondering if anybody has used that bearing in an NA and if so how well has it performed.