523 questions

[Gaboon]

I can attest that the gearset on the 1992 A523 trans I took apart has a very similar pitch to the 1989 A555 gearset I assembled onto the shaft.
The difference I did see is that the 555 gearset looked to be hardened or tempered more so than the 523. The 555 gears are black where as the 523 looked brownish or lighter in color.
This trans is going in my L body charger that weighs 2640 lbs with me in it and traps 128+ mph

[Reaper1]

I stripped A523 3rd

http://www.turbododge.com/forums/f4/...boom-help.html

So I went and read that story. Seems like this was a 2.5, ~23#'s boost, full weight '90 Daytona ES (guessing full weight, I know my Shelby Z was ~3100# with me in it). So from personal experience this is around the 250whp mark and well over 300ftlb probably (because 2.5). It broke seemingly during a hard (self described) shift from 2-3 according to the story and the clutch was a 4-puck and the wheels were spinning. I'm willing to bet that yes, the shift broke it. No, it wasn't the actual amount of power, but the shock loading from the whole driveline stopping and starting during the shift. Another thing is that you aren't making your max torque at the upper rpms that you will be shifting at or where they end up at after the shift, so the applied engine torque is actually less than your max torque. The gearboxes I see stripping teeth like this are almost always in an application where there are high shock loads. I have a friend that does drifting and he's chewed up I don't know how many 240SX gear boxes (all 3rd gear). Now, true, they aren't the strongest thing in the world to begin with, but they break them due to clutch kicking...very high shock loads...just like banging the crap out of gears.

I'm not saying that none of our boxes have failed due to just simple power, but what what I am saying is that I'm fairly confident that a vast majority of the gearset failures were due to other reasons.

I'm very interested in other people's accounts of breaking these transmissions. My goal isn't to make somebody feel like crap or put anybody down or anything like that. What would be nice to gain out of this is a sort of understanding as to where the actual breaking point might be.

[mopar-tech]

I'm not saying that none of our boxes have failed due to just simple power, but what what I am saying is that I'm fairly confident that a bast majority of the gearset failures were due to other reasons.

Can't say I agree based on what I broke in the past, and I have broke a lot of 'em.

I lost a 525 for example with a chrome moly plate in 3 laps at Summit Point in WV. Trans was installed right before the trip down and was fine at the 10 psi level. I started tangling with Joes tricked out GLHS and reduced the trans to scrap in short order at 20 psi. 2.5 at 20 psi on a TII Garrett with 3" exhaust makes wicked amounts of torque. He would get me in the corners but I'd reel him in on the straights. We parked the car in a pavailion and changed the trans out in 3 hours flat, I had brought a spare along just in case.

The factory 525/520/523 transaxles were rated only 180 ft/lbs, there was a reason a lot of cars had ramped up/limited boost targets to keep the trans from puking its guts.

Edit- Just to be clear, this was a fresh trans and everything was set right. It had not even been down the dragstrip yet.

[Reaper1]

Can't say I agree based on what I broke in the past, and I have broke a lot of 'em.

I lost a 525 for example with a chrome moly plate in 3 laps at Summit Point in WV. Trans was installed right before the trip down and was fine at the 10 psi level. I started tangling with Joes tricked out GLHS and reduced the trans to scrap in short order at 20 psi. 2.5 at 20 psi on a TII Garrett with 3" exhaust makes wicked amounts of torque. He would get me in the corners but I'd reel him in on the straights. We parked the car in a pavailion and changed the trans out in 3 hours flat, I had brought a spare along just in case.

The factory 525/520/523 transaxles were rated only 180 ft/lbs, there was a reason a lot of cars had ramped up/limited boost targets to keep the trans from puking its guts.

I was actually excluding the 525 simply because that tranny is a known weak tranny and the A520/523 is such an upgrade that unless that's all you have or you want to use for several reasons, then I don't think any of us would actually even contemplate using it.

I very much agree that the 2.5 has the capability of making stupid amounts of torque and it will be a much harder engine on transmissions than the 2.2.

It looks like from your story you were on a road course. What car? Do you know its weight? I'm sure this was a fairly long time ago, do you remember the circumstances where it first started showing signs of distress?

I'd like to take a second and point out that the development story behind the M4S "Wraith" included the problems they had with the transmission. I know they quoted around 440ftlb and given the time frame the car was being developed the only transmission they had available was the 525. They were eating them up like candy. They finally had to get a custom gear set made (actually 2 because the first attempt still failed). From what I've seen in pictures and of the car in person the transmission has at least a pump and oil cooler on it. I don't remember what they quoted for the weight of that car, but I'm going to take a stab at it and say that it's probably in the 2500# range given all the safety equipment, etc.

I think that given this information we can certainly all agree that the 525 is barely good enough for a slightly modded 2.2, much less a full bolt-on 2.5. I know of 1 anomaly personally, and Brent knows of another where the owners beat the living crap out of them (A525's) and they continued to live...even after the expected failure, but those are mostly likely the exception to the "rule".

[Gaboon]

I was actually excluding the 525 simply because that tranny is a known weak tranny and the A520/523 is such an upgrade that unless that's all you have or you want to use for several reasons, then I don't think any of us would actually even contemplate using it.

I very much agree that the 2.5 has the capability of making stupid amounts of torque and it will be a much harder engine on transmissions than the 2.2.

It looks like from your story you were on a road course. What car? Do you know its weight? I'm sure this was a fairly long time ago, do you remember the circumstances where it first started showing signs of distress?

I'd like to take a second and point out that the development story behind the M4S "Wraith" included the problems they had with the transmission. I know they quoted around 440ftlb and given the time frame the car was being developed the only transmission they had available was the 525. They were eating them up like candy. They finally had to get a custom gear set made (actually 2 because the first attempt still failed). From what I've seen in pictures and of the car in person the transmission has at least a pump and oil cooler on it. I don't remember what they quoted for the weight of that car, but I'm going to take a stab at it and say that it's probably in the 2500# range given all the safety equipment, etc.

I think that given this information we can certainly all agree that the 525 is barely good enough for a slightly modded 2.2, much less a full bolt-on 2.5. I know of 1 anomaly personally, and Brent knows of another where the owners beat the living crap out of them (A525's) and they continued to live...even after the expected failure, but those are mostly likely the exception to the "rule".

Only failures I ever had with the 525 was the diff. I went through those like candy. Oh, and I like candy.

[acannell]

So I went and read that story. Seems like this was a 2.5, ~23#'s boost, full weight '90 Daytona ES (guessing full weight, I know my Shelby Z was ~3100# with me in it). So from personal experience this is around the 250whp mark and well over 300ftlb probably (because 2.5). It broke seemingly during a hard (self described) shift from 2-3 according to the story and the clutch was a 4-puck and the wheels were spinning. I'm willing to bet that yes, the shift broke it. No, it wasn't the actual amount of power, but the shock loading from the whole driveline stopping and starting during the shift. Another thing is that you aren't making your max torque at the upper rpms that you will be shifting at or where they end up at after the shift, so the applied engine torque is actually less than your max torque. The gearboxes I see stripping teeth like this are almost always in an application where there are high shock loads. I have a friend that does drifting and he's chewed up I don't know how many 240SX gear boxes (all 3rd gear). Now, true, they aren't the strongest thing in the world to begin with, but they break them due to clutch kicking...very high shock loads...just like banging the crap out of gears.

I'm not saying that none of our boxes have failed due to just simple power, but what what I am saying is that I'm fairly confident that a bast majority of the gearset failures were due to other reasons.

I'm very interested in other people's accounts of breaking these transmissions. My goal isn't to make somebody feel like crap or put anybody down or anything like that. What would be nice to gain out of this is a sort of understanding as to where the actual breaking point might be.

I should also say that same A523 was probably the original one, with about 150k on it. And I had done dozens of 28 psi passes on full slicks with it years before it broke. Who knows what the original owners may have done..

[Ondonti]

i put a 93 523 in my reliant with a obx. the 568 is still on the shelf.

im not going to go totally insane and max everything out though. stock head, 50 trim, slightly ported 2 piece intake, stock exhaust manifold. i dont envision problems.

i did kill a 91 523 though but i still havent pulled it apart to see what i broke. it started making noise after a 2nd gear burnout and then made gravel in a tin can noises after a 2nd or 3rd gear roll on that hit 20psi.

Brian

So I went and read that story. Seems like this was a 2.5, ~23#'s boost, full weight '90 Daytona ES (guessing full weight, I know my Shelby Z was ~3100# with me in it). So from personal experience this is around the 250whp mark and well over 300ftlb probably (because 2.5). It broke seemingly during a hard (self described) shift from 2-3 according to the story and the clutch was a 4-puck and the wheels were spinning. I'm willing to bet that yes, the shift broke it. No, it wasn't the actual amount of power, but the shock loading from the whole driveline stopping and starting during the shift. Another thing is that you aren't making your max torque at the upper rpms that you will be shifting at or where they end up at after the shift, so the applied engine torque is actually less than your max torque. The gearboxes I see stripping teeth like this are almost always in an application where there are high shock loads. I have a friend that does drifting and he's chewed up I don't know how many 240SX gear boxes (all 3rd gear). Now, true, they aren't the strongest thing in the world to begin with, but they break them due to clutch kicking...very high shock loads...just like banging the crap out of gears.

I'm not saying that none of our boxes have failed due to just simple power, but what what I am saying is that I'm fairly confident that a bast majority of the gearset failures were due to other reasons.

I'm very interested in other people's accounts of breaking these transmissions. My goal isn't to make somebody feel like crap or put anybody down or anything like that. What would be nice to gain out of this is a sort of understanding as to where the actual breaking point might be.

The nissan transmissions ARE spreading gears. Three friends would strip them out in the middle of a pull (obviously its the culmination of previous abuse). One of them didn't give up on his car and just bought a 300zx transmission for his RWD sr20. The FWD guys are stuck having to buy aftermarket gears.

But our transmissions breaking like this at lower power levels is 100% FOD related. There are a million ways to create FOD in the transmission from various parts failing (often due to owner mistakes). The vast majority of cars are low horsepower so it again makes perfect sense that the breakage is happening on the cars that are the most plentiful. Simple statistics. Get ONE high HP guy to have this issue and everyone will start pretending its 100x over proven.

Robert Hassler broke a million transmissions with his stock tiny turbo Chrysler prototype 3.0 and others never break anything (even Chief with his forged motor prototype setup making the same stupid high torque levels, but he was known for being very thorough and careful). I have to assume he was doing something bad while driving. Other guys claim they have never missed a gear in their life (and of course I believe them!).

The small spline small gear 3.50 A543/523 transmission that I had fail was the one that I learned manual on, and it had 200k+ miles, with drag/street racing from the previous owner

[mopar-tech]

I was actually excluding the 525 simply because that tranny is a known weak tranny and the A520/523 is such an upgrade that unless that's all you have or you want to use for several reasons, then I don't think any of us would actually even contemplate using it.

The 525 and 520 main gearset isn't very different, the biggest change is the stronger diff.

What car? Do you know its weight?

86 Turbo Z Daytona with a/c, leather seats and 2 adults.

I'm sure this was a fairly long time ago, do you remember the circumstances where it first started showing signs of distress?

Sure. I was accelerating out of a turn on Summit Point and it sounded like popcorn going off in the transaxle.

We also killed one on the dyno doing a pull with Jon Genesky's CSX which had a 2.2 with a Super 60 turbo and NPR intercooler. Same thing, 3rd gear.

[mopar-tech]

Robert Hassler broke a million transmissions with his stock tiny turbo Chrysler prototype 3.0 and others never break anything (even Chief with his forged motor prototype setup making the same stupid high torque levels, but he was known for being very thorough and careful). I have to assume he was doing something bad while driving. Other guys claim they have never missed a gear in their life (and of course I believe them!).

FYI there is issues with the Ram guys running the NV3500? manual trans, they are known for being weak. There are guys who DO make them live but you have to drive like a grandma the majority of the time and shift like one too. Gus went through the same thing with the Mustang 4-speed in his turbo 302.

The transaxles we have are weak for the application, remember they started off behind engines making 84 hp and aside from the diff change have not changed very much. Production wise the 525-520-523 were rated at most for 180 ft/lbs of torque. No one at Mopar thought we would see the power numbers we are generating. I had one engineer get pissed off when I told him how much power the Reliant was putting out, he flat out stated the power train engineers lied about what certain parts would take for torque.

I'll give them a pass though, they did have to get out of the 7/70 period.

[Reaper1]

The 525 and 520 main gearset isn't very different, the biggest change is the stronger diff.

There was also the change to the case itself, the extra support for the diff, and the diff cover became cast aluminum instead of stamped steel (I'm taking a huge risk in guessing that helps with the strength of the tranny).

86 Turbo Z Daytona with a/c, leather seats and 2 adults.

So that is most certainly over 3000#'s...I'm going to guess more like 3500.

Sure. I was accelerating out of a turn on Summit Point and it sounded like popcorn going off in the transaxle.

We also killed one on the dyno doing a pull with Jon Genesky's CSX which had a 2.2 with a Super 60 turbo and NPR intercooler. Same thing, 3rd gear.

Given that these were 525's, then yeah, I can absolutely see gear spreading as being the main contributor of failure here.

FYI there is issues with the Ram guys running the NV3500? manual trans, they are known for being weak. There are guys who DO make them live but you have to drive like a grandma the majority of the time and shift like one too. Gus went through the same thing with the Mustang 4-speed in his turbo 302.

I've heard the same things in the Ram's. Gus's Mustang didn't have a T-5 in it? Even if that was the case, I understand that T-5's aren't exactly made of granite in stock form. I'm sorry, I'm a little ignorant on Ford manuals unless it's a T-5 based unit.

The transaxles we have are weak for the application, remember they started off behind engines making 84 hp and aside from the diff change have not changed very much. Production wise the 525-520-523 were rated at most for 180 ft/lbs of torque. No one at Mopar thought we would see the power numbers we are generating. I had one engineer get pissed off when I told him how much power the Reliant was putting out, he flat out stated the power train engineers lied about what certain parts would take for torque.

I'll give them a pass though, they did have to get out of the 7/70 period.

Absolutely! I agree! I've been wondering for years what the factor of safety is that they use for determining the advertised rated torque handling abilities of OEM gearboxes. I do know that they do take into account expected service life in terms of rotation count.

[mopar-tech]

So that is most certainly over 3000#'s...I'm going to guess more like 3500..

For a Daytona? No. Way.

My GTX with driver tips the scales at 3800.

My '89 Shelby Daytona was 3100 pounds on the E-town scales.

Given that these were 525's, then yeah, I can absolutely see gear spreading as being the main contributor of failure here...

CSX-T = 520.

[OmniLuvr]

I broke an early 91 (so 1990 build date) small spline 3.50 final 523 in my Shelby charger. pulled it from a Daytona with 120k on the odo, had a blown headgasket. it lasted 8 months of punishment at 18 psi (2.2, g head, flat top t3 pistons, 60-1 turbo, e85) the first time I turned it up to 20 psi, I stripped 3rd gear. from a roll in first gear, made a pull, slow shift to a solid pull in second, slow shift to third and as soon as full boost kicked it sounded like I had grenaded my engine, but it was 3rd gear. I put fresh oil in it when I installed it and never made noise while driving before this. haven't pulled it apart to inspect yet...

[Aries_Turbo]

We also killed one on the dyno doing a pull with Jon Genesky's CSX which had a 2.2 with a Super 60 turbo and NPR intercooler. Same thing, 3rd gear.

i remembering him nuking another at sdac13 doing burnouts by the hotel.

all this chatter makes me want to open up my broken 523 and see what broke.

Brian

[Reaper1]

For a Daytona? No. Way.

My GTX with driver tips the scales at 3800.

My '89 Shelby Daytona was 3100 pounds on the E-town scales.

My '88 Shelby Z was 3115#'s with me in it, 3/4 tank of fuel, and full size spare, full interior less the power seat as I had Viper seats in it by then. I'm figuring that, plus another 200#'s for the extra person, fuel, safety equipment. OK, maybe not 3500#'s, but you have to admit that 3300-3400#'s isn't out of the question here.

CSX-T = 520.

I didn't catch the CSX-T part I suppose.

[Reaper1]

Man, all this talk about people having issues with 520's...I've never had a problem and I was pushing 22#'s for years...dyno proven at 225hp/291ftlb at the wheels. Car would do 100mph through the traps (I never got a good launch so times never got in the 13's ) However, I don't really drag race that much and all the drag racing I did was with my 555 hybrid tranny. I did do a LOT of very hard driving on the 520, though. I will be pulling it out of the car soon, so I'll bust it down and see what she looks like.

[acannell]

Man, all this talk about people having issues with 520's...I've never had a problem and I was pushing 22#'s for years...dyno proven at 225hp/291ftlb at the wheels. Car would do 100mph through the traps (I never got a good launch so times never got in the 13's ) However, I don't really drag race that much and all the drag racing I did was with my 555 hybrid tranny. I did do a LOT of very hard driving on the 520, though. I will be pulling it out of the car soon, so I'll bust it down and see what she looks like.

When I broke my A523, I had been doing "experiments" with the Stage 5 FWDP cal by adjusting the AFPR seeing how much AFR I could get away with. I think I had it just over 12 AFR at 22psi or so and it was running WILD, very very fun time for that hour or so of freeway driving until I got near home and then started trying to time the launches..second launch was NASTY..tons of wheelhop and one tire fire, not even sure if the 2nd gear shift had pulled the cable out of the JB-welded repair on the shift cable. And that was the end....then I got an A568 for $450 shipped and its been in there ever since, but I haven't put it through nearly as much abuse.

The A568 has way better shifting points, much closer spaced and I enjoy driving it alot more than the A523. Worth it to change to the A568 just for that, seriously.

[Ondonti]

So if people are claiming the stack is actually seperating seriously on 200hp cars.....

Deflection is the shaft bending, and a greater pitch on the older 3.50:1 small spline 523/543 gears will decrease shaft deflection. Yes, smaller teeth will chew up with a smaller amount of deflection. The defect though would be the shafts themselves. People do not seem one bit worried about taking these 3.50:1 shafts and using them in hybrid transmissions with 3x the power as people supposedly overpowering the 3.50 geared transmissions.

IMO, the smaller gears with possibly worse durability would be more prone to serious damage when eating up FOD and therefore a damaged tooth would be a BIG problem with slight shaft deflection when your teeth are short. A damaged big tooth gear will not be as likely to fail with slight shaft deflection. Damaged teeth could be a problem without tooth deflection.

I see the big teeth being advantaged to avoiding warranty repairs for transmissions that are slowly eating themselves apart FOD wise (and probably not kept happy lubrication wise) and not anything to do with shaft deflection.

[acannell]

So if people are claiming the stack is actually seperating seriously on 200hp cars.....

Deflection is the shaft bending, and a greater pitch on the older 3.50:1 small spline 523/543 gears will decrease shaft deflection. Yes, smaller teeth will chew up with a smaller amount of deflection. The defect though would be the shafts themselves. People do not seem one bit worried about taking these 3.50:1 shafts and using them in hybrid transmissions with 3x the power as people supposedly overpowering the 3.50 geared transmissions.

IMO, the smaller gears with possibly worse durability would be more prone to serious damage when eating up FOD and therefore a damaged tooth would be a BIG problem with slight shaft deflection when your teeth are short. A damaged big tooth gear will not be as likely to fail with slight shaft deflection. Damaged teeth could be a problem without tooth deflection.

I see the big teeth being advantaged to avoiding warranty repairs for transmissions that are slowly eating themselves apart FOD wise (and probably not kept happy lubrication wise) and not anything to do with shaft deflection.

hey lets ballpark shaft deflection!!

from that thread awhile ago did you guys figure out how to calculate radial force when the gears transmit a certain force?

i.e. the "spreading" force that pushes the shafts apart on helical cut gears?

using that we could get an idea just how much deflection there is...I have my stripped 523 shaft still so I could measure it..but I sold the other shaft so someone would have to measure theirs

rough guess, a 1.25" OD, 8" long steel shaft supported on the ends, would deflect 0.002" at 500lbs, load in the middle

stiffness goes up as the 4th power of OD so we'll be needing to measure things to get anywhere near close

[Vigo]

So if people are claiming the stack is actually seperating seriously on 200hp cars...
Deflection is the shaft bending...
defect though would be the shafts themselves....
People do not seem one bit worried about taking these 3.50:1 shafts and using them...with 3x the power as people supposedly overpowering the 3.50 geared transmissions.

When you just look at those^^ major points of what Brent is saying I think it's pretty irrefutable that the vast majority of gearset failures (i.e. not the diff) have NOTHING to do with gear spreading.

[Ondonti]

When you just look at those^^ major points of what Brent is saying I think it's pretty irrefutable that the vast majority of gearset failures (i.e. not the diff) have NOTHING to do with gear spreading.

The guys I personally knew who had liberty straight cut dog boxes on their 8-9 second hondas, they disassembled them between races and they would not put back in parts that were damaged. If a tooth had a chip, it wasn't going back in, bad dog, etc. The reason was that they knew it was going to fail eventually, and 1-2k mile trips to race are not worth using bad parts. I would use worn parts on our transmissions. I have nothing important to risk and a lot to gain saving moderately used NS1 parts.
Their experiences gave me a very negative view of expensive FWD style manual transmission upgrades. I was totally shocked. I figured that you could go to zero breakage. You can't. If you build a custom box, holy crap think of the repair bill. There are dog box options on the 3000 gt's and the srt4's and how many good things have you heard about them long term? All I have ever heard of are expensive repairs and/or massive downtime. These guys don't know like the above mentioned honda racers that their transmission is now a consumable. The big market guys (VW, DSM, Honda) have the advantage that spare parts are available for their custom transmissions. The Honda guys accept that over their stock transmissions which could fail on the 1st pass.