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ITA SA22C Transmission Woes
Ok folks, ran into gearbox issues. I finished getting the race car ready last Tuesday and was planning on driving the car to BFH to attend driver's school on Friday. Anywhow, since I am unfamiliar with the service history of the car, I decided to change the gearbox oil. Mind you, the gearbox was shifting fine but I decided to be on the safe side since it was going to see track use. The old oil came out muddy and looked like coffee with cream and foul smelling. I put in two quarts of Lucas 75w90 GL4/GL5. Took it out for a test drive (car has full lighting and is plated and insured for the street) and everything was fine. The next night, I flushed out the cooling system and decided to take it out for another test drive. Came home, and drove it again after dinner. Started to have problems shifting into reverse and shortly after, I could not get it into 5th gear. Drove slowly home and tried to figure out what was wrong. I thought the gear oil was too slippery and so I added some Lucas Transmission Fix to help out the synchros. After a few minutes of shifting through the gears, 5th and reverse came back and was shifting smoothly. On Friday morning, I packed up and headed out to the track. I noticed that reverse had gone out again, but 5th was working fine. About 15 miles from home, I lost 5th, 4th and 3rd. Decided to bail out and limped the car home in 2nd gear with hazards on. I apologize for the overly long narrative but I wanted to be thorough in describing the situation. I've attached several photos to give some back ground on the gearbox. Its a 5 speed and has smooth housing. Pictures were taken when it was up on a lift whilst having a second muffler installed. I also took some pictures when I replaced the balky started. I will post additional photos.
https://cimg3.ibsrv.net/gimg/www.rx7...e549258bbd.jpg https://cimg6.ibsrv.net/gimg/www.rx7...8154ce545a.jpg https://cimg9.ibsrv.net/gimg/www.rx7...c9fd5390ac.jpg https://cimg0.ibsrv.net/gimg/www.rx7...2b59faf673.jpg https://cimg1.ibsrv.net/gimg/www.rx7...5a2eb5a81f.jpg |
1st and 2nd gear work fine but it simply refuses to go into 3rd, 4th, 5th and reverse. I took whatever covers that I can access in the shifter housing to help identify the gearbox. More pictures:
https://cimg4.ibsrv.net/gimg/www.rx7...c6501e53e3.jpg https://cimg8.ibsrv.net/gimg/www.rx7...3615f986bd.jpg https://cimg1.ibsrv.net/gimg/www.rx7...f7f46df39e.jpg https://cimg3.ibsrv.net/gimg/www.rx7...47537403e1.jpg https://cimg6.ibsrv.net/gimg/www.rx7...c8f41a07a7.jpg https://cimg7.ibsrv.net/gimg/www.rx7...489c996df6.jpg |
It sort of goes into 5th? if I gently angle the shifter upwards and to the right but I suspect that something is not aligned correctly. At this point, if the gearbox is buggered what gearboxes are a possible option. Should I look for the same identical gearbox or can I use a different gearbox that will work with the 12A engine and the SA22C chassis. What would be involved. Any suggestions, tip, tricks, etc. would be greatly appreciated. Thank you!
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Sorry you didn't make the race. It can be frustrating when you are getting started and this kind of stuff happens.
Not sure if this applies to all sanctioning bodies but the SCCA treats 79-85 RX7s as being the same car in Improved Touring. Yes there are differences but with the SCCA there is no penalty for installing an FB transmission in an SA. In 9 years of IT racing I used like 3-4 FB transmissions. I never fixed one, I just replaced them when a box developed syncro issues. Gear ratios - Rotary Tech Tips: Transmissions I never ran into the issues you are describing and I am not qualified to offer an explanation. I doubt this has anything to do with the lube that you used but rather there is something mechanically wrong with it. I have always used synthetic lubes of various weights with no issues other than those caused by heat. Since you are going to be running a stock transmission, I think you might get more assistance with repair/replacement by posting in the first gen sections. My advice would be to get your hands on at least two working transmissions and or find someone local that does RX7 or Miata transmission repairs. Threads on transmissions are common on this site and I would include searches on the 2nd gen forum because the NA transmission is basically the same as an FB. From a racing perspective and depending on your rear end gear ratio you only need the transmission to work really well in the gears you are using on track. For example I ran a 4.88 in my car (still do) and with a stock 12A engine/RX7 transmission I spent all my time in 3rd or 4th on track. I never went slow enough to use first or second and using fifth slowed the car down. So if I had a box with a dodgy 1st or 2nd gear I didn't care. I realize you drive your car to the track and need all of the gears to work but a crappy 2nd gear synco would not be a concern if I were you. Some other thoughts.....yes compared to a Miata, an RX7 shifts like crap but you will get used to it. Don't rush shifts with these transmissions, you will wear them out faster. A torque brace Engine Mounts/Bracing - Early Rotary & 1979-85 Mazda RX-7 will help with shifting because it keeps the shifter in one place no mater what you are doing. |
Originally Posted by mustanghammer
(Post 12344324)
Sorry you didn't make the race. It can be frustrating when you are getting started and this kind of stuff happens.
Not sure if this applies to all sanctioning bodies but the SCCA treats 79-85 RX7s as being the same car in Improved Touring. Yes there are differences but with the SCCA there is no penalty for installing an FB transmission in an SA. In 9 years of IT racing I used like 3-4 FB transmissions. I never fixed one, I just replaced them when a box developed syncro issues. Gear ratios - Rotary Tech Tips: Transmissions I never ran into the issues you are describing and I am not qualified to offer an explanation. I doubt this has anything to do with the lube that you used but rather there is something mechanically wrong with it. I have always used synthetic lubes of various weights with no issues other than those caused by heat. Since you are going to be running a stock transmission, I think you might get more assistance with repair/replacement by posting in the first gen sections. My advice would be to get your hands on at least two working transmissions and or find someone local that does RX7 or Miata transmission repairs. Threads on transmissions are common on this site and I would include searches on the 2nd gen forum because the NA transmission is basically the same as an FB. From a racing perspective and depending on your rear end gear ratio you only need the transmission to work really well in the gears you are using on track. For example I ran a 4.88 in my car (still do) and with a stock 12A engine/RX7 transmission I spent all my time in 3rd or 4th on track. I never went slow enough to use first or second and using fifth slowed the car down. So if I had a box with a dodgy 1st or 2nd gear I didn't care. I realize you drive your car to the track and need all of the gears to work but a crappy 2nd gear synco would not be a concern if I were you. Some other thoughts.....yes compared to a Miata, an RX7 shifts like crap but you will get used to it. Don't rush shifts with these transmissions, you will wear them out faster. A torque brace Engine Mounts/Bracing - Early Rotary & 1979-85 Mazda RX-7 will help with shifting because it keeps the shifter in one place no mater what you are doing. EDIT: BTW, after missing the first driver's school at BHF earlier this month (SCCA) due to carburation issues, I was determined to at least attend the classroom session so I got into my 1992 NA6 Miata and drove 2 1/2 hrs. to the track. Completed the classroom segment and passed the written test. I will have to wait until July for the next driver's school to take the track segment. Incidentally, it snowed on track the following day so the track segment was very messy from what I heard. Probably saved me from a bent race car. |
Same here! It rained and snowed during my driver's school in 2003. I survived but a few did not...
You can pull a transmission without pulling the engine. On my car I had to remove the exhaust ahead of the rear axle and the header. The drive shaft and starter will have to come out too. Don't forget the speedo-cable! The trick is to support the back of the engine, I do this with a bottle jack on the oil pan with a 2x4 to distribute the load. Or you can use tie down straps from the top of the engine to the core support in front of the engine. Either way, you have to support the engine because when you drop the trans mount, the engine will rock back on its mounts. I like using a bottle jack because you can make fine adjustments to the angle of the engine when you are removing and then later installing the transmission. If the transmission is going to be out for awhile you will want to use tie down straps along with the bottle jack because they can bleed down over time. When I pull a trans with the car on jack stands I use a floor jack to help hold the transmission. A helper that can raise and lower the floor jack is a plus. Also, if you don't touch the clutch you shouldn't have any issues getting a new transmission back in the car. Keep track of the bolt and where they go. Some of them are longer than the others. They are all 10mm 1.25 pitch except for the one under the starter which is 10mm 1.5 pitch. One thing that can make this easier, other than a lift....or paying someone else to do the work....is to make alignment pins using long 10mm 1.25 bolts. Pick some up at the hard ward store and cut the heads off and slot them for a screw driver. I usually put them across from each other where the factory alignment dowels are. They help on the removal and on the install of the transmission because they help keep things lined up. |
Just did my clutch this weekend and the only thing I'd add about pulling the transmission is that the top bolt on the engine (the one that holds on the engine lift point) does not need to come out. It works as an alignment stud and will help you on reinstallation. Also, don't forget to remove the clutch slave cylinder before pulling the trans and there's a few electrical connectors to remove too.
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SA transmissions are hard to find. The main difference between the SA (79-80) and FB (81-85) is the shiftier location. I'd get a couple of 1981-1985 trans if it where me.
I looks like someone may have been inside that trans based on the RTV between strans sections. If your lucky it could be an out of place shift fork. You'll need to pull the trans and split it to tell. |
The shifter location issue can be solved easily by swapping the SA tail housing onto the FB transmission. I believe you also have to swap over the 'selector fingers' (for lack of a better term), but that should be it. That is what I did when my transmission gave out earlier this year.
I know 81-82 transmissions work with the tail housing swap, and I'd assume the others do too, but I'm not certain. The SA transmissions also have a "top switch" - which the FB's don't - that does something with the stock computer related to emissions, although I doubt you have the stock system anyway based on that photo of your center console. :) |
https://cimg5.ibsrv.net/gimg/www.rx7...4a87e2a22c.jpg
https://cimg6.ibsrv.net/gimg/www.rx7...c45acc9602.jpg https://cimg7.ibsrv.net/gimg/www.rx7...51dc227c3b.jpg https://cimg8.ibsrv.net/gimg/www.rx7...da56974ecb.jpg https://cimg9.ibsrv.net/gimg/www.rx7...1009f8aa77.jpg https://cimg0.ibsrv.net/gimg/www.rx7...43b13dfd61.jpg https://cimg1.ibsrv.net/gimg/www.rx7...cf9fd29c09.jpg Gentlemen, thank you very much for all of the sage advice and information especially regarding the little tips and tricks that can make life easier. I managed to buy a spare transmission from a local SCCA member for 150.00 It appears to shift when I popped in my gearchange lever but I have not done anything else outside of that. I've attached photos of the replacement gearbox. Obviously need to be cleaned. It's not an SA22C (myu friend says its from an '85) so from what everyone has said, I'm going to have to switch out the tail housing? I'm going to have to order the shifter rebuild kit as well (form Mazdatrix). Should I first remove and disassemble the old gearbox first and see what is wrong before committing to a lot of work in swapping parts to make this newer gearbox work with my SA22C? Thanks again in advance. |
https://cimg9.ibsrv.net/gimg/www.rx7...74a2716188.jpg
@Benjamin - Yes, I took and re-wired the race car but left all of the stock factory wiring in place per ITA rules. I also relocated the twin MSD boxes from the passenger floor (which was directly above the hot exhaust system and muffler) to the dashboard. The original dashboard was a total mess with chunks missing and cracked all over so I made repairs and flocked it. I also installed a new Holley fuel pump and pressure regulator with bypass and replumbed the fuel lines so the re-built Nikki carbs are fed with a constant 3.5 psi. Car now starts more or less reliably but I can only get it to idle at around 1500 rpms which is a little bothersome on the street (car is plated so that I can drive it to the track) but should be ok on track. The Nikki carb has been stripped of all pollution devices and has been modified extensively for racing. https://cimg1.ibsrv.net/gimg/www.rx7...487ce9bc3b.jpg https://cimg3.ibsrv.net/gimg/www.rx7...97de025a79.jpg |
My thought would be to update the car as needed to accept an FB transmission. I guess that means opening up where the shifter comes through the tunnel but I am not certain. Others can chime in
My point is that it is a race car and all of the spares that you will have ready access to will be from FBs. So it would be easier to update the chassis than the gear box every time you need to swap in a transmission. Also, what ever you do for a trail shaft, make sure to inspect the bushing and seal. These cars have a harmonic vibration in 4th at around 7800-8000K rpms. In my experience, this vibration is worse if the tail shaft bushing is worn. Oh and I have a early style FB drive shaft that I purchased new from Mazda in 2007 or so. It only has race miles on it and was smother than any rebuilt I ever tried. It uses the small diameter pinion flange. Let me know if you are interested....would be cheap. |
So that transmission you picked up is a smooth casing which, from what I know, is what you want. Others know more about this than I, but there are some differences between the smooth and the ribbed transmission casings - what they are I do not know. Regardless, if you are going to swap tail housings I would start by opening up the old transmission since you'll need the 'selector fingers' and the tail housing anyway.
If want to try installing the FB transmission as-is you'll have a few issues, all of which could probably be solved with some time and patience. For starters, the shifter tower will not line up and will be located too far back (towards the rear of the car). This means you would need to cut the tunnel. You would also need the remainder of the shifter assembly from the FB trans, as it seems to be missing in your photos. In moving the shifter you will also find that the rubber grommets will not match, and the plate that covers the access hole will not either; the same will be the case with the center console too. As far as bolting up, yes, it should attach to the car with no modifications, the only issues are the shifter tower. I would just swap the tail housing for now because it's a relatively simple task. Cutting the tunnel to fit the other transmission will probably be more work than it's worth for the time being, and I would save that option until you go through another transmission or two. I might invest in another SA tail housing either by itself or from a junk transmission so that you can have a spare ready to swap in. The top switch shouldn't be a problem since you're not running smog equipment. |
Originally Posted by mustanghammer
(Post 12345938)
My thought would be to update the car as needed to accept an FB transmission. I guess that means opening up where the shifter comes through the tunnel but I am not certain. Others can chime in
My point is that it is a race car and all of the spares that you will have ready access to will be from FBs. So it would be easier to update the chassis than the gear box every time you need to swap in a transmission. Also, what ever you do for a trail shaft, make sure to inspect the bushing and seal. These cars have a harmonic vibration in 4th at around 7800-8000K rpms. In my experience, this vibration is worse if the tail shaft bushing is worn. Oh and I have a early style FB drive shaft that I purchased new from Mazda in 2007 or so. It only has race miles on it and was smother than any rebuilt I ever tried. It uses the small diameter pinion flange. Let me know if you are interested....would be cheap. |
Originally Posted by Benjamin4456
(Post 12345947)
So that transmission you picked up is a smooth casing which, from what I know, is what you want. Others know more about this than I, but there are some differences between the smooth and the ribbed transmission casings - what they are I do not know. Regardless, if you are going to swap tail housings I would start by opening up the old transmission since you'll need the 'selector fingers' and the tail housing anyway.
If want to try installing the FB transmission as-is you'll have a few issues, all of which could probably be solved with some time and patience. For starters, the shifter tower will not line up and will be located too far back (towards the rear of the car). This means you would need to cut the tunnel. You would also need the remainder of the shifter assembly from the FB trans, as it seems to be missing in your photos. In moving the shifter you will also find that the rubber grommets will not match, and the plate that covers the access hole will not either; the same will be the case with the center console too. As far as bolting up, yes, it should attach to the car with no modifications, the only issues are the shifter tower. I would just swap the tail housing for now because it's a relatively simple task. Cutting the tunnel to fit the other transmission will probably be more work than it's worth for the time being, and I would save that option until you go through another transmission or two. I might invest in another SA tail housing either by itself or from a junk transmission so that you can have a spare ready to swap in.a The top switch shouldn't be a problem since you're not running smog equipment. |
https://cimg7.ibsrv.net/gimg/www.rx7...3556896f02.jpg
https://cimg9.ibsrv.net/gimg/www.rx7...79261fd941.jpg https://cimg0.ibsrv.net/gimg/www.rx7...4554eac7bc.jpg https://cimg1.ibsrv.net/gimg/www.rx7...ed3c42e064.jpg https://cimg3.ibsrv.net/gimg/www.rx7...028789f1c0.jpg https://cimg4.ibsrv.net/gimg/www.rx7...004b8369be.jpg Ok, so I decided to take the replacement gearbox apart. I started with removing the tail housing and studying how this gearbox works. Some pictures. So these are the shfiter "fingers" that everyone is referring to. I see. There also seems to be a lot of junk floating around inside as evidenced by the corn kernels?!?! I've thinking it would be best to thoroughly flush the gearbox out before proceeding. What would you folks recommend for solvent? Kerosene, ATF? Can I pour the stuff into the opening and let swirl it around for a bit and then dump it out? Or is there a better way to do this? |
I prefer the shifter location of the FB over the SA tranny so was a no-brainer for me to notch the tunnel on my EP SA chassis. And as mentioned, SA trannies are difficult to find. As mentioned by Scott, I usually just replaced with a used unit over rebuilding. I always post third gear on my Pro7/ITA car.
For a short period I had an SA tranny in my 84 FB chassis. I remember down-shifting to third and accidentally hitting my relocated wiper switch(toggle) that was on the consule where the radio used to be. Very annoying at the top of turn two at Sears Point with the setting sun in your eyes. |
Originally Posted by kurtf
(Post 12346264)
I prefer the shifter location of the FB over the SA tranny so was a no-brainer for me to notch the tunnel on my EP SA chassis. And as mentioned, SA trannies are difficult to find. As mentioned by Scott, I usually just replaced with a used unit over rebuilding. I always post third gear on my Pro7/ITA car.
For a short period I had an SA tranny in my 84 FB chassis. I remember down-shifting to third and accidentally hitting my relocated wiper switch(toggle) that was on the consule where the radio used to be. Very annoying at the top of turn two at Sears Point with the setting sun in your eyes. |
https://cimg6.ibsrv.net/gimg/www.rx7...7e7b1e6a5d.jpg
Well I managed to pull the old gearbox out with the help of some of my friends. I started taking the tail housing off when I heard something rattling around inside. Proceeded to take the housing off to check the shifter fingers and to figure out how to transfer them over to the replacement gearbox. Here are some pictures. The SA shifter fingers are held in place by bolts whereas the FB shifter finger are secured with roll pins. I guess this is not going to work. BTW, I removed that one bolt to see what the diameter was and then I partially reinstalled it so that I won't lose it. |
https://cimg1.ibsrv.net/gimg/www.rx7...e83054102a.jpg
https://cimg2.ibsrv.net/gimg/www.rx7...d566ebc1c1.jpg https://cimg5.ibsrv.net/gimg/www.rx7...01bd602d5c.jpg Since I have nothing to lose at this point, I proceeded to take the gearbox apart further as an education. Some pictures. The gears seem to mesh smoothly and the entire assembly turns easily. At first blush, all the gears' teeth seem to be there whereas I was expecting it to look something like an old tobacco chewing hillbilly's mouth. Especially since there was something loose rattling around inside. More to follow. |
I made a short video of the SA gears and how they meshed.
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https://cimg6.ibsrv.net/gimg/www.rx7...03f7e14fe7.jpg
https://cimg7.ibsrv.net/gimg/www.rx7...b507a710b5.jpg https://cimg8.ibsrv.net/gimg/www.rx7...86aa65d207.jpg So this is what was rattling around inside. I'm going to take the intermediate housing off to see where the fastener fell off from. |
So I don't have enough time for a full out reply just yet, but don't worry about the bolts vs roll pins for the shift fingers. You'll need to use the roll pins from the FB tranny but that'll be it. I'll read through more in depth later when I have some extra time.
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https://cimg3.ibsrv.net/gimg/www.rx7...903f0a7279.jpg
Well, the intermediate housing came off easily and I quickly found where the bolt and washer had fallen off of. It appears to the the shifter fork that is inside the intermediate housing. Could this and the loose bolt getting jammed internally been the cause of all my problems? I gave the gears a cursory look over and I did not see any chipped or broken teeth. I'm hoping that a thorough cleaning and loctite + proper torque on all of the other fasteners will work. In the course of removing the gearbox, I found out that the four bolts that were holding the drive shaft onto the flange on the differential were actually finger tight! I guess the previous owner was in a rush to get the car finished for a race that he forgot a lot of stuff. I'm going to have to go through the entire drivetrain now. Anyway, I will clean and reassemble the SA gearbox and see if it shifts before I try re-installing it. Please feel free to chime in if you see something that needs addressing. Thanks Folks!! :worship: |
You are braver than I. I never took one this far apart other than to change rear housings after getting the rear bushing replaced. Hopefully you found the smoking gun!
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