shinka/10ae

Hi there,

I am in the process of rebuilding the transmission from my 1988 Turbo 2. The 5th gear synchronizer that I pulled out during disassembly appears to be a part that was replaced with a different part in 1986. The parts diagram from Foxed.ca, the pictures and description from Atkins rotary, and also the local Mazda dealer parts guys say that I should be using W501-17-725C. However, what I removed is identical to the pictures I have seen for V501-17-725.

Is it possible that I have a transmission from 1986 on my 1988 model year car? What is confusing me is that the date of the part change is 2 years before my car was manufactured.

From what I can tell it appears to be safe to use the newer part, but I still wanted to double check before I started putting things back together for my own piece of mind. Probably me being a bit paranoid, but since I couldn't find the answer in a direct search on the forum I thought it would be worth it to ask anyways.

Thank you for any help that you can provide.

Tim

j9fd3s

iTrader: (3)

also possible someone replaced the transmission at some point

Hot_Dog

The RX7 TII was first introduced as model year 1987. Apparently, the early TII transmissions (up to production date 01/11/1986) used 5th gear synchro V501-17-725.

What is the date of manufacture of your car? You've indicated that you have a 1988 TII, than you would use the 5th gear synchro W501-17-725C.

I think all ('87-'91) the TII transmissions were the same internally. So, Mazda might have just done a major design change to that synchro thus the change in p/n.

Hot_Dog

Looks like Mazda changed the clutch hubs for early (up to production date 01/11/1986) and late S4 TII transmissions.
R501-17-621 -6801
R502-17-621A 6801-
6801 FC33* -522333
That's most likely the reason behind the synchro p/n change.

Like j9fd3s mentioned, maybe your transmission was swapped out.

shinka/10ae

Thank you for your help. Do you know if there is a way to identify the year the transmission was made? I've been checking the housings to see if there is a stamp somewhere to indicate when it was built with no luck so far. Something similar to the letter stamps on the cast iron housings on the engine.

shinka/10ae

Thank you for your help. So I'm the second owner of the car and it did have the engine replaced at Mazda back around 2003. Maybe things have changed but I know that they didn't replace the transmission on my rx8 when that needed a new engine and I'm not aware that they replaced the transmission on the rx7. It's a 10th anniversary edition so I'm sure that it was built in 1988 and that is also what the VIN indicates. The information you posted about the clutch hubs is very helpful and I'll see if I can't figure out which specific part numbers I have.

shinka/10ae

Should have also mentioned that the previous owner gave me a lot of paperwork that he kept and there was no service records for either an engine or transmission replacement. Maybe did have it done and didn't mention it or keep the record if it but I have no other way of knowing.

Hot_Dog

So, I'm assuming that the car was driveable while you had it? How many miles on the transmission assuming it's the original? What problems were you having with the transmission?

shinka/10ae

I bought the car in 2001 with approximately 85K and it was my daily until I got my RX-8 in 2006 (135K when I parked it). I then stored it until we finally had a big enough garage to start working on it again in 2016. Having sat for so long, I decided to avoid the risk of starting the engine up and opted to overhaul it (good thing I did because the irons were in rough shape). The first to second gear shift was pretty rough before it was parked and, since I am rebuilding the engine and turbo, I decided to rebuild the transmission as well. If it is the original transmission then it has 135K miles of use.

j9fd3s

iTrader: (3)

sort of https://www.rx7club.com/general-rota...guide-1153243/
i notice that the really early transmissions have a different rib pattern on the bottom cover thing

shinka/10ae

Well I think that I got the answer to my question. It was pointed out to me that there are a different number of teeth between the two 5th gear synchronizers. The earlier synchro has 3 groups of 10 teeth whereas the later one has 3 groups of 11 teeth. The part that I pulled out of my car does strongly resemble the older version in appearance (it does not have any of the additional material removed beyond the 3 voids for the spring loaded keys that online pictures of the later synchro show). However, it has 11 teeth and therefore I need the newer version. Thankfully, my fears of an unknown transmission swapped at any point were not true. Thank you to the help that was provided and the advice offered.

Hot_Dog

Yes, that is most likely the case. You could always buy both and return the one that doesn't match up.