PreviouslyPlastic

iTrader: (1)

My newly acquired SA has a terrible noise while in 1st - 3rd, but not 4th and not sure of 5th (the noise is loud enough that I don't want to drive it more than around the block.
It sounds like ball bearings rolling around soup can and it only has this sound while accelerating. The noise seems proportionate to engine rpm, but is totally gone while in neutral or with the clutch in.

I changed the fluid hoping to make it go away... the fluid came out very dirty and had some metal flakes in it.. the noise got better, but it's still there... and now the fluid seems to be dirty and full of flakes again (maybe it just picked up more from what was left in the trans?)

I initially suspected/hoped it was the front U joint, but I have since replaced it and am now quite sure I'm screwed and need to rebuild the transmission.

I'm wondering if anybody has good/bad experience with rebuild kits, ideally ones from retailers within Canada.

I'm looking at the one from drivetrain.com... anybody have experiences? or better yet, an alternate fate to my SA? Maybe I can change the fluid again lol?

Cheers,
Kam

rx7lives

Sounds like a weird one. If it was the front bearing, you would hear the noise in neutral. If it was the throwout bearing, you would hear it with the clutch in. If it's the pilot bearing, you would hear it with the clutch in and the car in gear.

Is the frequency of the noise dependent on engine RPM or on car speed?

This thread has great info including a link to rebuild kits but if you're going to do some tranny work, buy yourself a top of the line snap ring pliers set and don't get one from harbor freight. I bought one from them and it self destructed the first time I used it on a small snap ring. I bought the Craftsman one with replaceable pins and it is very robust.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/sa22-trans-rebuild-994554/

PreviouslyPlastic

iTrader: (1)

Thanks for the reply and link, I will definitely look into it further.

The noise goes up proportionately with engine rpm in pitch and seems to be there right from when the car starts rolling (~1500) to ~5000. I don't want to take it much higher than that with all the noise it's making....
Actual vehicle speed seems irrelevant, but it is definitely effected by the load I put on it (via throttle inputs).

Are there any special tools I will need for the rebuild other than a pair of good snap ring pliers?

Thanks!
Kam

rwatson5651

iTrader: (5)

You will need a gear puller that will reach down the mainshaft to pull the gears (resist the urge to try to prise them with a pry bar as the gears are brittle and you can chip them),( don't ask how I know) and you will need deep (and I mean very deep) well socket to torque a special nut on the main shaft for re-assembly. I was able to use a chisel to remove the nut but had to buy a socket and then have a welder cut the base of the socket from the mouth and weld a 17 inch piece of pipe for re-assembly. I have pics if you need it. Also the manual says to always replace the nut with a new one. I found the replacement at the Mazda dealer. You will also need feeler guages and calipers to set clearences and you MAY need to come up with some shims to adjust the clearences. You can pretty much fine them at McMaster Carr, if you are willing to search their extensive catalogue. You will also need a plastic or dead blow hammer to persuade some of the pieces. Resist the urge to use a metal hammer. Also, my advice is to make a very complete diagram of everything you take off the shafts including which way they face, front or rear. And one last thing, you need to pick up a large basket of patience, this is a doable project, but it can be frustrating.

Also, judging from your symptoms I hazard a guess that you have a bad intermediate shaft bearing. When you are in 4th gear the torque goes straight down the main shaft and the intermediate shaft "sees" no torque, that would explain why the noise goes away while in 4th.

rwatson5651

iTrader: (5)

Here are picks of the socket I had made:


and one of the special nut:

j9fd3s

iTrader: (3)

if it makes noise in every gear except 4th, its the center countershaft bearing. the whole trans needs to come apart to change that, so you might as well do all the bearings and synchros, along with any other worn out parts

84stock

iTrader: (5)

I would just swap in a second gen tranny and appreciate the taller 5th gear ratio

PreviouslyPlastic

iTrader: (1)

Watson, Thank you for posting the picture, I'm sure I will be replicating that part when it comes time.

I read through this thread: https://www.rx7club.com/showthread.php?t=994554
and noticed there was some confusion about which rebuild kit to buy...
It seems Drivetrain.com only carries one now with a 15mm wide single ball front countershaft bearing. Is this correct?

Finally what's this about shift forks wearing out and "building up" material to remedy this? Is this a "weld and grind" type of repair? Sounds sketchy....
Drivetrain.com doesn't seem to carry forks and neither does the dealer...

Thanks all for the replies,
It's time to get my hands dirty!

Kam

PreviouslyPlastic

iTrader: (1)

Oh shoot, it looks like they carry both kits.
Has the confusion been settled as to which kit will be needed for my SA?

Kam

rwatson5651

iTrader: (5)

I dont guess there is any way to tell for sure which one you need without taking yours apart and measuring the front countershaft bearing. Mine had the 20 mm bearing but I have no information on how to tell which cars had which.

On the shift forks you will see the issue when you take yours apart. The conventional fix is to replace them with new ones if you can find them, mine were within spec so it was not an issue for me. You may find them at the dealer, if not then the only alternative is the "weld and grind" remedy, I guess it is a little sketchy, but a machinist could put them back right easily.

rwatson5651

iTrader: (5)

one more thing, I did not know about it when I rebuilt my trans, but mazda published a seperate manual for transmission rebuilds. I bought one on e-bay but have not received it yet. You may want to consider acquiring one of these manuals to help with your rebuild. It covered '79 and 80 transmissions.

PreviouslyPlastic

iTrader: (1)

I heard mention of that manual, but can't seem to find it on eBay.
It isn't the same as the factory service manual's section on the transmission is it?
Somebody posted this:
https://www.rx7club.com/attachment.p...7&d=1334216905

Is that the one?

I think I'm going to have to do exactly what you described, take it apart, measure, then order a kit...
In the mean time I'm going to get the car licensed and hopefully find a supplier for a rebuild kit near me...

Do you think it would do much more damage to drive the car a couple of miles to get it safety certified? (Ironically, I don't think I will have a problem passing safety with a "dead" trans).

Thanks!
Kam

rwatson5651

iTrader: (5)

Yea, that pic is the manual I was talking about. I had to search through about 90 pages of "mazda manuals" to find it. It should be much morre in depth than the FSM is.

I dont believe a couple of miles will make a big difference, but I prob wouldnt go much further, You will be replacing the bearings and syncros, but that leaves a lot of things you will be reusing so I would be carefull. Those metal flakes will take their toll of the remaining parts.

rx7lives

Does anyone know if the six speed from either the Miata or RX-8 will fit with a minimum of work. It would be nice if the shifter location and rear cross member would fit but no doubt I'm being optimistic.

PreviouslyPlastic

iTrader: (1)

Assuming you mean one of the cars in your sig;
my trans won't even swap without some modification it seems....

http://www.mazdatrix.com/g1.htm

There's mention of a miata gear set, but no mention of an rx8... I think the work needed to swap in an rx8 trans would be similar to that needed to swap in a totally different make... but I could be wrong.

Cheers

j9fd3s

iTrader: (3)

i have had a couple 04-08 Rx8 transmissions, so i looked at those, the 09-012 should bolt up the same, but i don't have one, so i'm not sure.

anyways you need the trans, and the Rx8 starter. the trans bolts up to the engine, but you need the turbo sized clutch and flywheel. you also need a turbo sized driveshaft.

the Rx8 shifter should just about line up with the SA's tunnel, but for the FB you need to take other 6speed trans parts (probably the miata) and you can move it back enough to work for an FB/FC

the Rx8 uses a power plant frame, so it doesn't have a trans mount, it does have a big stud in about the right place so it shouldn't be hard to fab something.

the Rx8 2-6th ratio's are basically the same as the competition transmissions, so its geared for acceleration. cruising RPM on the freeway will be about the same as a 12A trans car. 1st is a granny gear.

rx7lives

Well, I suppose, when I rebuild my LSD and use a new ring and pinion, I can gear it for good mileage on three freeway and use the RX-8's granny gear to make up for the change in gearing.

Kentetsu

You know what else sounds like marbles rolling around in a coffee can, only during acceleration? Pre-ignition/spark knock.

Just thought I'd throw that out there since you mentioned that as a symptom....


.

PreviouslyPlastic

iTrader: (1)

You're scaring me.
No reason it would spark knock in 1st - 3rd but not 4th though... and it wouldn't seem to be coming from the trans tunnel.... right? right?! *faints*
Also fwiw, I can rev the car in neutral without any issues..... infact I quite enjoy the sound of it haha

PreviouslyPlastic

iTrader: (1)

So, I did it. I rebuilt the trans, new bearings and synchros...
I went ahead to install it and it was all great....... for about 50ft.

While "test shifting" with the car off the ground (but engine running and wheels spinning) I was able to enter all 5 gears and reverse.
During my test drive I had some trouble leaving 3rd gear the first shift, and then it flat out would not come out. I ended up limping it back home and into the driveway still in 3rd.
Regardless how I rock the car, clutch in or out, engine on or off it won't leave 3rd gear.

I know I'm going to have to remove the trans and tear it apart again to see where I screwed up, but has anybody had this happen before? I feel as if the synchro clutch keys are wedged in a weird way not allowing my synchro clutch hub sleeve to slide anymore...

Anybody? Please? =(

j9fd3s

iTrader: (3)

could be that, could be the detent *****, could be one of the hub sleeves is backwards/mixed up... there are a bunch of things it could be. the good news is that they are all stupid, the bad news is that you have to pull it apart...

rwatson5651

iTrader: (5)

Years ago I had this problem. Newly rebuilt trans in my SA got stuck in 3rd gear. I figured out the only way I could get it out was to start taking it out of gear without the clutch AND while giving it a little gas. Otherwise it would not come out no matter what I did. Never did figure out what the problem was. Drove it that way for a while, then ditched the trans and replaced it with a low milage junk yard unit.

PreviouslyPlastic

iTrader: (1)

By hub sleeves do you mean the things that slide back and forth on the synchronizer hubs? They have a direction to them?!?!?! Eff.

Thanks,
Kam

swbtm

iTrader: (2)

Bringing this one back for a question.

First off, ever get your transmission out of 3rd?

Second, has anyone been able to locate a copy of the transmission rebuild manual lately?

https://www.rx7club.com/attachments/...trannybook.jpg

I have not been able to find anything on ebay, google, or similar.

Has anyone been able to scan theirs to send to foxed?

Thank you

PreviouslyPlastic

iTrader: (1)

Yup.
Turned out I was an idiot and forgot to put a snap ring back on.
The helical cut nature of the gears would cause the 3/4 hub to push forward all the way when torque was applied, this caused the synchro to mash so hard against the hub that it was stuck in 3rd. You couldn't pull it out because the three tab things on the hub had popped out by then leaving me screwed. The snap ring goes in front of the 3/4 hub. This took me 5 tear downs to figure out..... On the bright side I can now drop my trans in about 90 minutes lol.

I just used the FSM's transmission section as well as an exploded diagram from some other manual. All found from foxed.ca

Good luck!
Kam