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1G Need Help Deciding on Transmission

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EagleGarage

Proven Member
32
6
Feb 19, 2017
Richardson, Texas
Alright so I've got a fully built 6 bolt, cp pistons, bc rods, the whole 9. Running a hx40 and hoping to make something in the neighborhood of 600-700hp to the wheels, my question is what trans do you guys recommend out there for this sort of power level? I know of jacks, and TRE and came across xtreme performance. Shep isnt building dsm trannys anymore I'm assuming? If I had the money I would go with a full blown dogbox but really and truly I don't have 7 grand lying around. Im not looking to spend more than $3000, let me know what you guys think
 
Jacks, TRE and TMZ. They are all very reputable. Should ask Tim @twicks69 at TMZ which combination is the best for your goal. He is in this forum and he is a very knowledgeable person.
https://www.tmzperformance.com/awd-dsm/

Within your budget, probably DSM gears with shot peening or wpc treatment, or could be combined with Evo gears.
Yes a dogbox costs really high and a bit noisy and harsh, but that was definitely the best upgrade I have ever done on my car.
If twice you break a good built transmission, actually it would be almost the same amount of money as a dogbox.
 
Auto, or the aforementioned shops/freelancers. Don't forget about @bastarddsm as a well rated, somewhat fresh vendor/FL, and @twicks69 is THE man for trans knowledge, as well as super cool and helpful.

What will you be using the car for?
 
Auto, or the aforementioned shops/freelancers. Don't forget about @bastarddsm as a well rated, somewhat fresh vendor/FL, and @twicks69 is THE man for trans knowledge, as well as super cool and helpful.

What will you be using the car for?
It’s gonna be on the streets LOL, just looking for an all around well built street car that you can drive to the track
 
Jacks, TRE and TMZ. They are all very reputable. Should ask Tim @twicks69 at TMZ which combination is the best for your goal. He is in this forum and he is a very knowledgeable person.
https://www.tmzperformance.com/awd-dsm/

Within your budget, probably DSM gears with shot peening or wpc treatment, or could be combined with Evo gears.
Yes a dogbox costs really high and a bit noisy and harsh, but that was definitely the best upgrade I have ever done on my car.
If twice you break a good built transmission, actually it would be almost the same amount of money as a dogbox.
Thanks, I’ll send him an email and see what he suggests
 
Just remember, it doesnt matter who builds it, it's still based on oem mitsu gears designed for 200hp. If you make 600+ and use it, it will break eventually.
So you’re saying it doesn’t matter what “stage” transmission build I go with? They’re going to break regardless? Just a matter of how long one lasts than the other? Sorry for nube questions, I’m not very educated on transmissions, just basic functions
 
Yeah, but even stage vs stage there isn't much difference. The biggest difference is one built with all new gears, or one built with used stuff. Theoretically the all new one should last better, as it doesn't have any fatigue built up.....but in practice I'm not so sure that's the case. I feel mitsu started to "jimmy cracked corn" these things, and the new repair parts are not as good as some of the older original shit. It's hard to get a real picture of the data because no 2 transmissions are used the same.

Some stages include shot peening and other metal treatments. I don't, as I don't feel like it's a good value to the customer. There is sound science in shotpeening, but the factory gears are already shotpeened, and then we are using them at 2-3x the designed value. Shotpeening is good for like 25%, not 100% increase in fatigue strength - and that's only if it's done right. Were talking like nasa level engineering studies type of done right. For uncle Jimbob in the backyard spraying shot at a part with a homemade blaster, and no research behind it, maybe 10% gains can be had.

There is 2 types of gear failures that we see in these transmissions, high cycle fatigue failure, and straight ultimate strength failure:
We see fatigue failures on the 3rd gear, intermediate shaft and center diff gears. In my experience, the intermediate shaft gives up first due to being used as an idler, this is a common failure in a 600hp street car that makes a lot of highway pulls.
We see straight up ultimate strength failure on 4th gear in drag use. 4th gear just doesn't have enough rim strength for the teeth attached to it, and it rips them off. We also see this in the later model 3/4 slider, as well as input shaft and some first gear failures.

Stil though gainz is gainz, if you get that 10-25% gain it would help, but the problem is what happens when you spend an extra $300 on shotpeening, and you grab 4th hard and it shit's the bed. All the shrapnel goes through the trans and destroys your extra "investment". You would have been better off saving that money for the next trans.

So there ends up being several possible scenarios. If your a 400hp street car guy and you only make highway pulls, shot peening may actually be a good investment. If your a 800whp drag guy, it would be a terrible investment.

As for how to make them last?

Don't powershift into 4th - your et is already decided by then.

Minimize the 3rd gear pulls - when I was younger and made less power and running bottom 11's I would do back to back to back 3rd gear pulls. Trans would last a summer, and shit the bed. Making a pull from bottom RPM, brings the motor through a huge torque spike when full boost hits. - During a drag pass it's likely you'd never see that. Now I keep my street boost down at 20psi, and make 500whp. I rarely stand on it - side effect is that I'm not used to it, so it feels like a monster when I do. It's really rare to find something during normal street driving that 500whp won't run down. Then when I go to the track put her back on kill. I got almost 3 seasons out of my last trans.

Don't sidestep the clutch - Don't use a 700ft*lbs clutch when a 500ft*lbs clutch will do.

Like I said in previous posts, if your a 600+hp car and you use it, treat the transmission as a consumable. The sooner you come to terms with that, the better off you'll be. If you can't accept that you need to get in a rwd auto - even some of the bigger rwd stick shift transmissions are not that much better.
 
Yeah, but even stage vs stage there isn't much difference. The biggest difference is one built with all new gears, or one built with used stuff. Theoretically the all new one should last better, as it doesn't have any fatigue built up.....but in practice I'm not so sure that's the case. I feel mitsu started to "jimmy cracked corn" these things, and the new repair parts are not as good as some of the older original sh**. It's hard to get a real picture of the data because no 2 transmissions are used the same.

Some stages include shot peening and other metal treatments. I don't, as I don't feel like it's a good value to the customer. There is sound science in shotpeening, but the factory gears are already shotpeened, and then we are using them at 2-3x the designed value. Shotpeening is good for like 25%, not 100% increase in fatigue strength - and that's only if it's done right. Were talking like nasa level engineering studies type of done right. For uncle Jimbob in the backyard spraying shot at a part with a homemade blaster, and no research behind it, maybe 10% gains can be had.

There is 2 types of gear failures that we see in these transmissions, high cycle fatigue failure, and straight ultimate strength failure:
We see fatigue failures on the 3rd gear, intermediate shaft and center diff gears. In my experience, the intermediate shaft gives up first due to being used as an idler, this is a common failure in a 600hp street car that makes a lot of highway pulls.
We see straight up ultimate strength failure on 4th gear in drag use. 4th gear just doesn't have enough rim strength for the teeth attached to it, and it rips them off. We also see this in the later model 3/4 slider, as well as input shaft and some first gear failures.

Stil though gainz is gainz, if you get that 10-25% gain it would help, but the problem is what happens when you spend an extra $300 on shotpeening, and you grab 4th hard and it sh**'s the bed. All the shrapnel goes through the trans and destroys your extra "investment". You would have been better off saving that money for the next trans.

So there ends up being several possible scenarios. If your a 400hp street car guy and you only make highway pulls, shot peening may actually be a good investment. If your a 800whp drag guy, it would be a terrible investment.

As for how to make them last?

Don't powershift into 4th - your et is already decided by then.

Minimize the 3rd gear pulls - when I was younger and made less power and running bottom 11's I would do back to back to back 3rd gear pulls. Trans would last a summer, and sh** the bed. Making a pull from bottom RPM, brings the motor through a huge torque spike when full boost hits. - During a drag pass it's likely you'd never see that. Now I keep my street boost down at 20psi, and make 500whp. I rarely stand on it - side effect is that I'm not used to it, so it feels like a monster when I do. It's really rare to find something during normal street driving that 500whp won't run down. Then when I go to the track put her back on kill. I got almost 3 seasons out of my last trans.

Don't sidestep the clutch - Don't use a 700ft*lbs clutch when a 500ft*lbs clutch will do.

Like I said in previous posts, if your a 600+hp car and you use it, treat the transmission as a consumable. The sooner you come to terms with that, the better off you'll be. If you can't accept that you need to get in a rwd auto - even some of the bigger rwd stick shift transmissions are not that much better.
Very useful info, looks like I know what I’m gonna go with based on this information. Easy on the 3rd gear pulls, stay light on it and as you said, use it as a consumable not as a warranted trans from the factory.
 
Right
Yes, durability is definitely different. But what @bastarddsm meant is even the straight cut gear dog box can be broken occasionally. Nothing is unbreakable.
Right, I get nothing is made to last forver but it’s just sounding like you can’t expect any kind of transmission to last more than a couple years if you want to take the car out during the week and drag race it on the weekend
 
I'd recommend an auto at this point, I think they'll have a longer service life especially when built correctly. You don't get to row gears, but there's no denying the consistency and power handling from even a stock unit.
 
I’ve come to the conclusion to try and keep enjoying my car at the 400-450ish horsepower mark because everything is still working together LOL. I know at some point my trans will give up, but I think if you don’t have thousands to invest on whim to maintain a 600+ hp set up than it’s maybe better to just be happy with what you have. I’ve been eyeing a bigger t3 setup for a loong time now, but I’m affraid of abandoning a setup now that works, and diving into a scenario of one thing after another breaking, so this year she might just get a paint job and coil overs LOL
 
Right

Right, I get nothing is made to last forver but it’s just sounding like you can’t expect any kind of transmission to last more than a couple years if you want to take the car out during the week and drag race it on the weekend

It's not just DSM transmissions. It's everything. Don't get me wrong a PPG is lightyears better than a mitsu trans, but they still wear, and they still break. in some respects they are easier to f*** up than a mitsu trans.

Look at it this way if you make 600whp, that typically a mid 10's car if it works well. Look at any other platform and see what's holding up running mid 10's. In fwd/awd stuff, seems like evo's stay together decent, buy they still fail. Honda's hold up ok, but they don't make any torque, and they still do break. In rwd stuff, your generally looking at a big dollar th400, or powerglide. No one can seem to figure out how to keep a 4l60 together, Fords your going to be in a build C6. Stick shifts, everyone is going to be on a t56 or some race trans like a liberty or jerrico. yeah some fox body guys get t5's to sort of live, but they still break, and so do the aftermarket gearsets for them. All of these are bug huge transmissions compared to us, and they still break, and need yearly maintenance if you run them hard.

It's just how it is. If big power was easy, everyone would do it, and cars like a demon wouldn't be 100k+. Like I said before you need to accept that if you make power your going to work on it. If you can't it's just gonna end in a partout.

Someone mentioned automatics, yes they are somewhat tougher than a 5 speed, but only sorta. The big draw is if you can get a good convertor, and get up on it, they can be faster easier. Durability, I'm not convinced. Lots of odd failures are starting to show up these days. Convertors go away, and your stuck waiting/hoping you get the same one back ect. I think a big part of the apparent durability, is that it is harder to do dumb(abusive) shit with them than it is with a 5 speed. As far as them being quicker, ehh. My shitbox is no racecar and it's so far from dialed in it's crazy, but look at it's best pass. 9.80@144 with a 1.5x 60', Not many auto's ET much better for that trap speed, and the ones that do are usually "race" cars with lots of lightweight parts, good suspension, and a really really well dialed in setup. Lets look at a slower pass from my car, this fall with the boost turned all the way down 21psi. It run a 10.99@125mph with a 1.50 60'. Again, not much quicker for that mph, and I was fighting a warped to shit ACT2600 and a hurt second gear synchro. As far as I care, all of ya switch to auto's and leave me the 5 speed parts LOL.
 
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There are a few tricks that may help to keep a transmission together. By themselves they won't do much, but all together, they add up.

-Shot-peening and treatment of gears, as mentioned
-Transmission cooler that sprays over 3rd & 4th
-Gentler clutch with a sprung hub (non-puck)
-Keep torque down (stay 2.0L with a modest turbo. If it spools fast, pull some boost or timing at peak torque to prevent spikes. Stay under 450 ft-lbs)
-Remove weight
-Don't money shift it, or do back-to-back pulls in 3rd and 4th
-Use the best gears and hubs for the job

If you do the above and treat it well, it should last a long time.
 
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looollllzerz. had too.
#noautomaticsneeded

you were talking about going 10.99@125 and not much room for et imporvements. fwiw heres my tuners time slip on his old auto 1g at around the same boost with a hx40. full weight auto car.
 

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I said that I'm not seeing many automatics being that much quicker for the mph. The pass you reference is only 2 tenths quicker, but it's also a mph faster. I've attached a snip from a well known et predictor. These are ideal times for a 125 and 126mph. As you can see the automatic really isn't any closer to the ideal ET for that mph. Either way it really is 6 of one, half dozen of the other.
 
Depends on the torque being made. I put down nearly 400 wheel torque and was breaking 3rd gear with maybe 5k miles on the transmission. TRE shot peened the gear sets which radically improved the fatigue strength to the point I wasn't shattering 3rd anymore, I could just beat on it. Shot peening will not increase the ultimate strength substantially, it's not for that purpose. This was with the EVOIII 3rd gear set from TRE, along with shotpeening everything else. I assume 3rd gear was already shot peened but the point was things stopped breaking after that. For 700 wheel h.p. I think you will be replacing transmissions regularly regardless.

And if you only have $3000, you won't be able to afford that level of horsepower. I had upgraded the my TRE transmission (3) times. I must have spent $6,000 if not more over (3) transmissions, with TRE covering parts on (2) of (3) transmissions.
 
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