It Blowed Up Real Good! (Now With Pictures!)...AGAIN...and again!
04-16-09, 10:24 PM
#54
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At least we have a general idea of what kind of abuse an N/A transmission can take. 400+hp with WOT pulls and some times at the strip with hard launches seems promising. I guess if you were running a stock N/A clutch and F/W you would last less than a month on running the car that hard with the power you're putting out.
I hope you just bite the bullet and put a TII drivetrain in there. You can still put it in there, and not let anybody know about it.
04-17-09, 02:08 PM
#55
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And now, the damage!
Last night I disassembled the transmission to take a look at the destruction. Having not taken a transmission apart before I was surprised that it was quite easy. Just pull the front cover, remove a snap ring holding the input shaft bearing, pull the rear shifter box (there is a split pin you need to drill out), remove the long bolts holding the case together, pull the tailshaft housing and then split everything apart with the aid of a hammer. Very easy.
Hmmm...There seems to be something missing from these gears. I'm not sure the technical name for these gears, so I'll call them the "input gears". Obviously this is the issue with my transmission. As the damage occurred in 3rd, these two gears took the brunt of the torque. This explains why only 4th worked. As these gears transfer power to the cluster shaft for all other gears, if they are totalled, then nothing but 4th is available.
So knowing what I know now about what's broken, I think I may fix it. I happen to have another NA transmission with a snapped input shaft. It looks like I could just undo two snap rings, then slide the broken gears off of the shaft and slide a good set back on. Any flaw in this plan?
Last night I disassembled the transmission to take a look at the destruction. Having not taken a transmission apart before I was surprised that it was quite easy. Just pull the front cover, remove a snap ring holding the input shaft bearing, pull the rear shifter box (there is a split pin you need to drill out), remove the long bolts holding the case together, pull the tailshaft housing and then split everything apart with the aid of a hammer. Very easy.
Hmmm...There seems to be something missing from these gears. I'm not sure the technical name for these gears, so I'll call them the "input gears". Obviously this is the issue with my transmission. As the damage occurred in 3rd, these two gears took the brunt of the torque. This explains why only 4th worked. As these gears transfer power to the cluster shaft for all other gears, if they are totalled, then nothing but 4th is available.
So knowing what I know now about what's broken, I think I may fix it. I happen to have another NA transmission with a snapped input shaft. It looks like I could just undo two snap rings, then slide the broken gears off of the shaft and slide a good set back on. Any flaw in this plan?
also on the mazda transmission the two gears you broke, are the input shaft, and the countershaft. the input shaft basically stops after that first gear.
it does look fixable, although with all those gear teeth bouncing around in there, there may be damage to some of the other gear teeth. and like the motor, if its apart, you look at synchro's and hubs and bearings and stuff too which is where it gets expensive
the FSM has an adequate trans rebuild section, it does lack in pictures, so a couple pics while you're taking it apart are a good idea, just so everything goes back together right, as it probably wont work at all if its not right. there are a couple special tools (really deep socket, and some long bearing pullers) which are nice to have but with a little creativity you can do without em. might be easy to borrow, as every dealership has had a set (or three)
its a slightly different skillset, but if youre smart enough to build your own intake and engine, and not blow it up, the trans rebuild might be a fun challenge
04-17-09, 02:55 PM
#57
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At least we have a general idea of what kind of abuse an N/A transmission can take. 400+hp with WOT pulls and some times at the strip with hard launches seems promising. I guess if you were running a stock N/A clutch and F/W you would last less than a month on running the car that hard with the power you're putting out.
I hope you just bite the bullet and put a TII drivetrain in there. You can still put it in there, and not let anybody know about it.
I hope you just bite the bullet and put a TII drivetrain in there. You can still put it in there, and not let anybody know about it.
I'm not big on using a TII transmission for philosophical reasons but if it comes down to it, I will. There's no harm in doing so. For the time being though I'm going to stick with the NA rear end. I have a freshly rebuilt GXL LSD waiting to go in.
also on the mazda transmission the two gears you broke, are the input shaft, and the countershaft. the input shaft basically stops after that first gear.
it does look fixable, although with all those gear teeth bouncing around in there, there may be damage to some of the other gear teeth. and like the motor, if its apart, you look at synchro's and hubs and bearings and stuff too which is where it gets expensive
its a slightly different skillset, but if youre smart enough to build your own intake and engine, and not blow it up, the trans rebuild might be a fun challenge
Some do, some don't. The ones I'm looking at appear to be held on by snap rings.
04-17-09, 07:48 PM
#58
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ive done a bunch over the years, they arent as cool as the motor, but still are kinda fun.
yeah too bad the input shaft is broken on the other one, cause then you'd probably be all set
04-18-09, 12:50 AM
#59
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Aaron heres some really good tutorials on complete disassembly and rebuild of a FD tranny they're almost identical on the inside, between this and the FSM you should be good to go
http://www.davidgeesaman.com/
you can make that long socket by cuttin a spare impact socket in half and weldin a pice of pipe between it
Did you rebuild the lsd???...if so do tell lol
http://www.davidgeesaman.com/
you can make that long socket by cuttin a spare impact socket in half and weldin a pice of pipe between it
Did you rebuild the lsd???...if so do tell lol
04-18-09, 08:10 AM
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sorry for the double post, but i was just looking at the pic, if the counter shaft on your other junk tranny is good, you could use that, remove that bearing with a puller and the gear will either be held on by snapring or maybe a nut everything is pressed on to the main shaft
the counter shaft is the only solid one
the actual gears themselves are under 100 bucks, i know with some of the mazda FWD transmissions people will use the 3rd gear from the AWD 323 turbo because they are hardened and they are around $65 for 3rd gear
the counter shaft is the only solid one
the actual gears themselves are under 100 bucks, i know with some of the mazda FWD transmissions people will use the 3rd gear from the AWD 323 turbo because they are hardened and they are around $65 for 3rd gear
04-18-09, 10:56 AM
#61
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I kind of jumped the gun on the LSD. The diff is going out to be rebuilt soon. I use "London Driveline" for stuff like this. But I hear it's a pretty simple operation to just replace the clutch packs.
11-09-09, 01:21 PM
#62
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So, um, it happened again.
Yesterday I was out for a drive with some friends. 10 minutes out of the city we had a clear road ahead but were stuck behind a truck pulling a trailer at half the speed limit. The car ahead of me pulled out and passed, I followed by dropping it to 3rd and putting the fun pedal down. Literally exactly as the first post in this thread describes, the transmission tore itself apart as the engine just crossed 5,000 RPM at 14 PSI. I was treated so the same shattering-crunching-grinding-breaking noise as before, and had no gears but forth.
I was able to limp home in 4th, which was a lot of fun as I happened to hit every freaking red light as I drove through the city from the highway to my house.
I think it's safe to say I have found and confirmed the power handling limit of the NA transmission. Above 450 RWHP, they can be broken at will by a little throttle in 3rd.
With winter fast approaching (though ironically, the weather is above 15 degrees C and no rain for the rest of the week, compared to the last two weeks which were down near zero with rain every day) I'm just going to park the car for the remainder and get to work on the stuff I planned for the winter. At this moment, the transmission shop should be just putting the finishing touches on a TII transmission I am having them build. I spoke of using a T5 earlier, but I got the TII transmission for no money locally and it was in really great shape. I'm just having it rebuilt with new bearings, syncros and seals. During the winter I'll make the swap and then never have to worry about transmission failure again.
Yesterday I was out for a drive with some friends. 10 minutes out of the city we had a clear road ahead but were stuck behind a truck pulling a trailer at half the speed limit. The car ahead of me pulled out and passed, I followed by dropping it to 3rd and putting the fun pedal down. Literally exactly as the first post in this thread describes, the transmission tore itself apart as the engine just crossed 5,000 RPM at 14 PSI. I was treated so the same shattering-crunching-grinding-breaking noise as before, and had no gears but forth.
I was able to limp home in 4th, which was a lot of fun as I happened to hit every freaking red light as I drove through the city from the highway to my house.
I think it's safe to say I have found and confirmed the power handling limit of the NA transmission.
Above 450 RWHP, they can be broken at will by a little throttle in 3rd.With winter fast approaching (though ironically, the weather is above 15 degrees C and no rain for the rest of the week, compared to the last two weeks which were down near zero with rain every day) I'm just going to park the car for the remainder and get to work on the stuff I planned for the winter. At this moment, the transmission shop should be just putting the finishing touches on a TII transmission I am having them build. I spoke of using a T5 earlier, but I got the TII transmission for no money locally and it was in really great shape. I'm just having it rebuilt with new bearings, syncros and seals. During the winter I'll make the swap and then never have to worry about transmission failure again.
11-09-09, 03:01 PM
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Keep in mind I never really drove around worrying about the NA transmission before. I had the car at the 1/4 mile probably 15 times, and beat on it almost daily for two years before I started breaking things. With boost around 13 PSI at the low side of 400 RWHP, I didn't have much of a problem. With boost at a solid 14 PSI (HKS EVC) now at the higher side of 400 RWHP, they seem to break easily.
This one was hurt when I was tuning 16 PSI a few months ago. It only took about 3 runs at 16 PSI before it had acquired a whine in 1st, 2nd and 3rd. 500 RWHP? I think so!
This one was hurt when I was tuning 16 PSI a few months ago. It only took about 3 runs at 16 PSI before it had acquired a whine in 1st, 2nd and 3rd. 500 RWHP? I think so!
11-09-09, 08:38 PM
#69
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Glad to see you bit the bullet and went with a t2 tranny. I think you definitely found the "line in sand" for the n/a trannies in general. What was your philosophical objection in the first place? I couldn't understand why you were willing to go to a t5 over the tried and true t2.
Off topic, do you have the link to the info on your porting? Id like to mimic it for my upcoming build. I can't remember how you went about it but I do remember your porting being more well thought out than most people's. I've been meaning to pm you about it.
Off topic, do you have the link to the info on your porting? Id like to mimic it for my upcoming build. I can't remember how you went about it but I do remember your porting being more well thought out than most people's. I've been meaning to pm you about it.
11-10-09, 08:52 AM
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I was quoted $1050 for the rebuild including bearings, seals, syncros and misc. It would be considerably cheaper (by about $300) if syncros weren't being replaced but I thought it was silly to have the whole thing apart and not do the syncros.
I have always wanted my car to be a true "turbo NA", which means not just tossing TII parts onto it. Such a thing (modifying what is there, fabricating required parts, etc.) is more in line with traditional hotrodding and the way I think, as opposed to just buying a TII drivetrain and bolting it on. Going with a T5 has many advantages such as ubiquity of parts, many gear selections, large aftermarket support, and low cost. But faced with how cheaply I picked up the TII transmission and running the effort vs. the cost of rebuilding the TII unit and just bolting it on, I decided to go the TII route. It's also nice my shifter will end up in the stock location, as opposed to having to fabricate linkages and such for the T5.
I don't suggest you mimic my porting. What I suggest will depend on your power goals and use of the car.
Glad to see you bit the bullet and went with a t2 tranny. I think you definitely found the "line in sand" for the n/a trannies in general. What was your philosophical objection in the first place? I couldn't understand why you were willing to go to a t5 over the tried and true t2.
Off topic, do you have the link to the info on your porting? Id like to mimic it for my upcoming build. I can't remember how you went about it but I do remember your porting being more well thought out than most people's. I've been meaning to pm you about it.
11-10-09, 01:18 PM
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i rebuilt the trans for my P port car (bearings/hubs/synchros/forks) and it shifts so nice, its way way way better shifting than the 74k trans in the FC
11-11-09, 10:32 AM
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