Busted Transmission

[pboglio]

This is going to sound strange, but everything within the tranny imploded without a single oil drop leaving the trans. Case looked good though.

I'm just tired of imploding transmissions, it keeps delaying my engine rebuild. I'm putting my hopes on the shot peening and tranny cooler.

 

[->PrOjEcTGS<-]

It makes sense why everyone keeps on breaking 3rd gear. Whether or not you're in 3rd when it breaks doesn't matter. Your first post says you were in 2nd at the time of the breakage. In our transmissions the center diff is driven off of the 3rd gear on the intermediate shaft. Therefore if you're making tons of power in 2nd you could definitely shear the teeth off of the intermediate shaft's 3rd gear. This is also why none of your other gears worked. Since the teeth were missing off of the intermediate shaft no power was getting to the center diff to turn anything.

Now, if some one would make an affordable aftermarket intermediate shaft that is stronger than stock that would make our trannies a lot beefier.

That sucks. I'd like to see some pics when you get them.

 

[pboglio]

Dogbox is the only real significant upgrade. What you can do to a stock tranny is limited to gear detailing, better oiling, shot peening, micropolishing, bearing preload adj. That is like taking a 2g connecting rod, doing the above, and expecting it to hold together at 600 w.h.p. I prefer to just go bigger.

The intermediate shaft is cast. It'd be a hell of alot stronger if it were forged, if that were even possible to cut the gears that way. In the end, everything is based off a stock gearset, that is what makes me skeptical.

 

[pboglio]

Tranny was rebuilt by Jon and Eric @ TRE yesterday. I have to thank them for turning around the build in 1 working day. I used another tranny with low mileage & low horsepower use for the rebuild core as it was more suitable and in alot better condition.

What was done as follows:

-New 2g input shaft (magnefluxed, shot peened)
-Reused intermediate shaft (from different low mileage/horsepower tranny) (magnefluxed, shot peened)
-New EVOIII 3rd gear w/double synchro(magnefluxed, shot peened)
-New EVOIII 4rth gear w/double synchro (magnefluxed, shot peened)
-Reused Center differential
-Reused Front differential
-New 1st/2nd & 3rd/4th shift fork
-New synchros all around
-New bearings, oil seals, filters, etc. etc.

The detail work can be seen in the pics. Basically in a nutshell, I'm benefiting from the closer ratio 3rd and 4th EVOIII gears & ALOT of detail work on the 3rd gear of the intermediate shaft. Shot peening of ALL components. On top, ALL parts were magnefluxed. I can't stress this enough, anybody wanting to do their own rebuild would be clueless as to any potential cracks. Jon saw a crack on a part, the part got tossed. What this means is that he is "cherry picking" parts for the build that either don't have cracks or are within acceptable tolerance such as runout on input & intermediate shafts.

O.K., being an engineer I wanted to know a root cause. Obviously, cars are running higher torque then what is speced for these DSM trannies. And as mentioned, 3rd gear on the intermediate shaft is also turning the center differential. Story goes that RRE was having trouble with tossing trannies left and right on the roadcourse. After seeing tranny temps just running away during datalogging, Jon @ TRE asks RRE to stop using BG synchroshift and switch over to Redline MT-90. Tranny temps drop back down to acceptable levels and no more busted trannies on the roadcourse. BG viscosity was decreasing and shearing down, allowing gear contact and increasing friction, temps increased and viscosity decreased, etc. Redline MT-90 viscosity actually INCREASES as it gets hotter, from a 70 weight to 85 weight.

 

[pboglio]

A few more pics of the new tranny and the carnage of the intermediate shaft.

 

[toofast82]

Nice writeup, good to know about the fluid, too! Bet you can't wait to get it back in

 

[pboglio]

Oh yeah, can't wait to get the thing back on the road For those that are interested, my total out the door was $1465. Me and Jon talked options, and for roadracing the taller EVOIII 1st gear made no sense and the 4 spider center differential upgrade is only needed for those launching hard off the line.

Found a couple good links about gear technology and metal improvement processes such as shot peening:

www.engineersedge.com
Metal Improvement Company

 

[olmytsi]

Nice!!!!!!!! I need to drop mine and take it somewhere...too lazy right now, i hate dropping the trans in a 2g.

 

[dsm-onster]

Basically in a nutshell, I'm benefiting from the closer ratio 3rd and 4th EVOIII gears. . .

As a drag racer, this is the exact reason why I DO NOT want evo gears in my tranny. 4th gear has a .863. With the stock final drive ratio and stock tire diameter, you have to rev to 9000rpms to get to 127mph in 4th. So you have to shift into 5th with any car that has over 550whp and full weight. It's great for dodging trees in the bush. and probably good for auto-x. But for the drag racer not having to shift into 5th is a benefit. You can always significantly increase the stock tire diameter I guess. 55% aspect ratio to 65% aspect ratio takes you to 136 at 9000rpms in 4th with the evo gears. But then you're putting alot more load on the transmission gears since it's like changing to a taller final drive ratio.

Just imagine, the evo final drive is geared even lower than the awd dsm. That's only 115mph at 9000rpms in 4th gear.

 

[pboglio]

As a drag racer, this is the exact reason why I DO NOT want evo gears in my tranny. 4th gear has a .863. With the stock final drive ratio and stock tire diameter, you have to rev to 9000rpms to get to 127mph in 4th. So you have to shift into 5th with any car that has over 550whp and full weight. It's great for dodging trees in the bush. and probably good for auto-x. But for the drag racer not having to shift into 5th is a benefit. You can always significantly increase the stock tire diameter I guess. 55% aspect ratio to 65% aspect ratio takes you to 136 at 9000rpms in 4th with the evo gears. But then you're putting alot more load on the transmission gears since it's like changing to a taller final drive ratio.

Just imagine, the evo final drive is geared even lower than the awd dsm. That's only 115mph at 9000rpms in 4th gear.

Pros and cons to everything Matt. Jon and I talked about it, for instance, I avoided the EVOIII 1st gear, EVOIII input shaft, & the 4 spider center differential upgrade due to cost. Those mods are typically well suited to drag setups though but were of little use on my ride. I like the tight ratios of my STi. Where I drive keeping a nice tight 2nd,3rd, & 4th keeps me in the powerband. The "hub slider" with the EVOIII 3rd & 4th looks alot thicker than what I previously had due to the double vs. single synchro construction and the EVO 3rd & 4th gears come from the factory shot peened already.

As you can tell, I'm not really a drag racer. The car is going thru some changes and hopefully will see auto-x and roadcourse duty in a year or so

 

[dsm-onster]

I know . I just WISHED there were an gear that could suit us drag guys since AWD happens to be a good drag platform in general.

 

[pboglio]

It's alive I finally got my ride running again. The ACT 2600 clutch with street disc is a bear trap, not so much as the increased pedal effort but the fact the engagement distance has been cut in half. Shifting gears feels like a mini clutch dump every time. Hopefully with the clutch break-in completed this will get better. I didn't notice a huge difference with the lighter 11 lb chromoly flywheel but the nasty vibration I had at 6500 rpms from the lightened stock flywheel is completely gone. Took a few minutes to get used to the clutch but it isn't too bad launching it.

The EVO3 3rd and 4th gears are barely detectable, I'm getting 3300-3400 rpms at about 45 mph in 3rd now. I'd have to say they probably aren't worth the upgrade price at this point.

The FP race exhaust manifold, 7cm turbine housing, and 02 housing are going out for swain-tech ceramic coating next week. There is just too much radiation coming off that manifold and its affecting my intake temps severely.

The Kelford 272 cams and FP Beehive springs and AL retainers go in after I get my car smogged.

Overall, I got the car running good considering the hot weather, pumpgas and 2.5" highflow cat I'm now running for the smog certification. It'll be a good 2 months before I'm ready to take it to the track or dyno but so far its good to have the eclipse up and running again.

 

[toofast82]

It's alive I finally got my ride running again. The ACT 2600 clutch with street disc is a bear trap, not so much as the increased pedal effort but the fact the engagement distance has been cut in half. Shifting gears feels like a mini clutch dump every time. Hopefully with the clutch break-in completed this will get better.

It will get better, I installed an ACT 2600 almost 2months ago and about 1500miles.
The clutch smoothened quite abit after about 350miles. The pedal effort dropped to a comfortable feeling as well as the engagement distance increased some. The pedal took quite a bit of effort at first though Could be I was so used to driving my beater Integra Now the ACT doesn't seem like much more effort than the Teg after it broke in.

I think the benefit of the Evo 3-4 is more so the strength increase and higher rpm engagement

 

[pboglio]

Yeah, the EVO3 3rd and 4th gears are shot peened from the factory, but I had that done to the rest of my gears anyways. My STi has a heavy pedal, so the ACT2600 wasn't a big deal in terms of pedal effort, just the shorter engagement distance. That combination in addition to a 3 lb lighter flywheel makes things reeeeeaaally touchy.

That had me sweating a bit trying to get the car out of the garage for the first time as I stalled it 4-5 times. After a couple of drives I'm getting the feel for it. I'm gonna need all the luck I can get holding the trans together this time.

 

[PIMking]

My FP manifold is killing my temps too. I was going to heat wrap it. okay back to topic..

 

[olmytsi]

Mine is alive too haha, bought a TRE stage 3 trans and put it in 10 days ago

 

[dsm-onster]

I'm gonna need all the luck I can get holding the trans together this time.

No, just don't go full throttle and shift when the tranny is cold like you said you do elsewhere .

 

[pboglio]

Yeah, I won't have to worry about shattering gears in cold weather for quite some time, doin like 100*F over in ChicagoWTF Even with the brutally hot intake temps (i.e. +120"F), a restrictive cat and only 20 psi, car still feels great on the topend. I think the 11 lb flywheel is definitely helping out quite a bit over the 14 lb one I had in before.

Trans is breaking in nicely, had a funny grind going into 3rd gear at anything around 3000 rpms. That is going away now but the trans is still notchy like an S.O.B. I'll be taking it very easy on this trans until the Tilton pump and tranny fan go in. For now just trying to get thru the break-in period.

The FP manifold is putting out more radiation than Chernobyl at this point. Brakes are pulsing pretty badly, so it's time for some new rotors. Then I strip off half my mods and go in for a smog test, efing pain in the ass.

 

[1fastlaser]

As a drag racer, this is the exact reason why I DO NOT want evo gears in my tranny. 4th gear has a .863. With the stock final drive ratio and stock tire diameter, you have to rev to 9000rpms to get to 127mph in 4th. So you have to shift into 5th with any car that has over 550whp and full weight. It's great for dodging trees in the bush. and probably good for auto-x. But for the drag racer not having to shift into 5th is a benefit. You can always significantly increase the stock tire diameter I guess. 55% aspect ratio to 65% aspect ratio takes you to 136 at 9000rpms in 4th with the evo gears. But then you're putting alot more load on the transmission gears since it's like changing to a taller final drive ratio.

Just imagine, the evo final drive is geared even lower than the awd dsm. That's only 115mph at 9000rpms in 4th gear.

I went threw the traps at 134@7700rpms with evo 4th. Im running a 225/50/16

Opps old post .

 

[dsm-onster]

Yea kind of old post . I can't remember. My math could very well have been wrong. Good to see that you didn't have to go much over the stock rev limit at all.

 

[pboglio]

The EVO III 4th gear is about 125 mph at 7000 rpms. Compared to a 6 speed STi, I can barely detect I'm running shorter gears in the DSM. The difference isn't big at all but the shorter 3rd gear is more convenient on the street.