awd 5 speed transmission are strong?

[fastnelson]

Hi everyone , can an dsm awd 5 speed transmission do low 8's ? or can keep it up with an 1200+awd engine? has anyone done it yet? i have an friend that needs to built an transmission but he don't want to go for the dog box.

NBF

 

[donniekak]

This isn't a 3s. Aftermarket support for dsm's is second to none. There are several shops that can built a trans to your needs. I would call shep, he runs 7's on the awd drivetrain.

 

[fastnelson]

This isn't a 3s. Aftermarket support for dsm's is second to none. There are several shops that can built a trans to your needs. I would call shep, he runs 7's on the awd drivetrain.

i know that but he don't want to go with the dog box yet.

 

[hubz91talontsi]

You dont have to do a dog box. WELCOME TO TRE## WE SPECIALIZE IN MANUAL TRANSMISSION REPAIR
Sheptrans.com: Specializing in Performance Nissan GTR Transmissions, DSM Transmissions and EVO Transmissions
Jacks Transmissions LLC — Welcome

 

[turbo addict]

I would be very surprised if you could go that fast. the gears on the dsms' are not very strong and have a tendency to loose their teeth at power levels much much lower than you are looking at. If You don not go with a dog box you are just using different combinations of stock gears either dsm or evo3 either way they will break, often. If you do find something out let us know, but to my knowledge no one makes a stronger aftermarket gear set for dsms that is not a dog box.

 

[Bricktop]

You probably don't want to But, Ever thought about going Automatic?

 

[fastnelson]

You probably don't want to But, Ever thought about going Automatic?

That's what i told him , but for some reason he doesn't like autos and already told him to call John (sheptrans.com).

Thanks guys.

NBF

 

[dsm-onster]

Stock transmissions? no. Worked transmissions by Shep, TRE, Jack, TMZ, dogbox racing? yes.

 

[pboglio]

Short answer is no. No DSM tranny can "keep up" with 1200 h.p. You would be looking at a very short lifespan. I'd recommend a tranny cooler, amsoil synthetic gear oil, and shot peening of the entire gearset. This is straight from TRE and the fact the factory EVO and STi's come shot peened say's something.

 

[dsm-onster]

Amen! and by "short" you mean one race, right?

 

[pboglio]

The lifespan would be measured in minutes.

 

[donniekak]

The lifespan would be measured in minutes.

Most of my builds are between 4-500ft/lbs, and i'm feeling good if they make it to 12k miles.

 

[fastnelson]

So, the auto would be the way to go than to make an couple low 8's, with out going dogbox?

 

[twicks69]

Nelson, in this circumstance, the HP is not the only number I would be interested in knowing. What kind of Torque is this setup doing?

As for the engine configuration, I am assuming that you are using a 6G72 variant? Would you be using a JDM non-turbo AWD 6G72 bellhousing on a 1G transmission case then? (that is what the JDM non-turbo AWD 5-speeds are for reference) The guts of this transmission are 1G AWD DSM turbo parts and 2G-style mounts, and it utilizes a DSM AWD clutch on the 6G72 AWD flywheel if I recall.

As for power levels, personally, PPG dogbox would be the smartest way to go if you intend on utilizing a DSM AWD transmission gearset/case or a built auto AWD at this kind of power level.

What chassis is the engine/drivetrain going to be used in? DSM, 3SI, Other?


By the way, Nelson, your car is truly impressive! I have been following it for some time on 3SI.org. By far one of the craziest AWD imports in the USA!

 

[Wilsonman02]

I saw the "dogbox" on shepracing.com, it doesnt have much info about it. What exactly is a dogbox tranny?

 

[twicks69]

I saw the "dogbox" on shepracing.com, it doesnt have much info about it. What exactly is a dogbox tranny?

1st to 4th DRAG set - Mitsubishi Evo 1-3 - Pfitzner Performance Gearbox

A dogbox refers to a dog-engagement synchro-less transmission. Sometimes referred to as a "crash box", because it requires you to literally force it into gear with authority. There are no synchros to slow down the gears for the hub/slider to engage the gear you are selecting.

This design is stronger and more effective for fast shifting when being compared to a synchro helical transmission. Clutchless shifting can be done on a straight-cut dogbox without issues by just reducing the throttle (taking the load off the gears so it shifts faster and easier) and shifting with authority.

The straight cut gear design is substantially stronger than a helical design with the downfall being substantially increased gearset noise. The upside is strength.

As well, PPG is well known for their material composition, surface treatments and isotropic finishing on their transmission gearsets. I would classify them as one of the best in the business of building race transmission components.

As for selling the PPG gearset, Shep is the only one with rights to sell it in the USA.

If you are looking for a helical dogbox, there are a few options, including Albins Gear.

Places like Dogbox Racing, and Liberty Gear are known for plating the stock gears with dogrings by machining them down and welding on the dogring assembly. Now you have faster shifting abilities, but still have weak gears when comparing them to PPG products.

 

[rock1t]

i think only people who have spent 3k on their tranny should speak.

so. i will.

do a stock rebuild at a reputable shop in your hometown. it's not how much power your transmission will hold. it's when it is going to break.

and i don't recommend shep. you are more than welcome to come here and drive my shep stage 3 tranny. and when I tell you I have under 2k miles, you will think you are driving something that has 140k.

 

[AK Maniak]

i think only people who have spent 3k on their tranny should speak.

so. i will.

do a stock rebuild at a reputable shop in your hometown. it's not how much power your transmission will hold. it's when it is going to break.

and i don't recommend shep. you are more than welcome to come here and drive my shep stage 3 tranny. and when I tell you I have under 2k miles, you will think you are driving something that has 140k.

Did you honestly expect a stage 3 tranny to feel like a brand new stock one? Im sure my RS shifts "smoother" than yours but that doesn't mean shit.

 

[rock1t]

Did you honestly expect a stage 3 tranny to feel like a brand new stock one? Im sure my RS shifts "smoother" than yours but that doesn't mean shit.

No, I have had many built transmissions. Just never in my DSM till this one, and the transmission was great for a while, but then slowly started grinding. Syncromesh can only help so much. I only been to the track a few times and I was starting to have issues.

Replaced my fork and pivot ball, shifter cables, and shifter. Still no luck. Highly recommend just a factory rebuild, since my $3k tranny didn't make it to 2k miles.

In my camaro, I had 430 horse and 397 torque, built tranny, and that one lasted me almost 20k miles.

 

[1fastlaser]

What kind of fluid are you/or did you run? How is your adjustment, how is the clutch pedal assembly? How is the master,slave cylinder? Theres alot of other stuff that needs to be 100% for a trans to work perfectly. Usually the guys that have a bad clutch pedal assembly, and everything not adjusted right with a clutch dragging are the ones saying how crappy there new rebuilt transmissions are.

I dont consider a transmission with factory gears "built". There just rebuilt stock transmissions. Thats like calling a 2g piston 6 bolt motor with stock rods and acl race bearings "built".

 

[rock1t]

What kind of fluid are you/or did you run? How is your adjustment, how is the clutch pedal assembly? How is the master,slave cylinder? Theres alot of other stuff that needs to be 100% for a trans to work perfectly. Usually the guys that have a bad clutch pedal assembly, and everything not adjusted right with a clutch dragging are the ones saying how crappy there new rebuilt transmissions are.

I dont consider a transmission with factory gears "built". There just rebuilt stock transmissions. Thats like calling a 2g piston 6 bolt motor with stock rods and acl race bearings "built".

clutch pedal assembly new. running redline mt90. master and slave new. new fork, new pivot ball. new shifter cables. brand new spec stage 3+ clutch. everything was running good. it was just one of the final launches.

and when this tranny does finally go. i will use a stock rebuild. save me lots of money.

 

[Lofty]

HP doesn't kill transmissions, torque does.

There are reasons why I don't prefer Shep's transmissions either, but I don't feel like badmouthing someone publicly. I would go somewhere else. Probably to someone that's active in the DSM community and active on these forums.

There's not a whole lot to a transmission. It's mainly about assembly is what makes it last. Shot peened, Properly deburred gears...

Anyone can throw in double syncros and all that, but if you don't take care of the actual assembly of the transmission itself, it's not gonna last.

 

[pboglio]

Sure, torque does. But cyclical failure is also the culprit, fatigue failure. This is where the shotpeening helps out. For instance, Titanium as an example has a tensile strength of about 500-700 MPa on a static load test, but at 10 million cycles it drops to 140 MPa. Shot peening can improve the fatigue strength to about +30%. So, you can see the more cycles you have, the radically lower the failure point. This is where electro-polishing and/or shot-peening can help out with prevention of crack propagation.

Another culprit can be heat treat. Get the gears hot enough, I'm talking about localized temps right at the gear tooth interface and not bulk oil temps, and whatever heat treat process the gears went thru to increase the tensile strength of the base steel could get cooked right back out of it.

I've seen my gearsets taken apart, the gear wear is absolutely enormous on a built transmission due to the high gear stack preloads. Then toss in an ungodly amount of torque, and the thrust loads can create a ton of extra frictional forces that strips the gear face of material. On my stock intermediate shaft at 60,000 miles the thing looked like I pulled it out of the bag brand new, which I happily reused on my "built" tranny. The failed intermediate shaft off my built tranny had unbelievable amounts of surface wear.

Helical gears, high gear stack preloads, and high torque don't mix IMHO. Thats where the straight cut gears make sense. NO gearstack preloads, NO thrust forces, much much lower sliding frictional forces. Just pressure forces on the gear face to deal with.

 

[rock1t]

HP doesn't kill transmissions, torque does.

There are reasons why I don't prefer Shep's transmissions either, but I don't feel like badmouthing someone publicly. I would go somewhere else. Probably to someone that's active in the DSM community and active on these forums.

There's not a whole lot to a transmission. It's mainly about assembly is what makes it last. Shot peened, Properly deburred gears...

Anyone can throw in double syncros and all that, but if you don't take care of the actual assembly of the transmission itself, it's not gonna last.

I was not bad mouthing. I was just sharing my experience with a company that is well known for dsm trannies. (or used to be).

I'm sure you can search and find the same problems I am having from other users of these transmissions. It's just my recommendation to go with a stock rebuild and save you $2k. Unless you have money to throw around. You can drive sensible and still have fun, and when it breaks again, you aren't out the added cost of a per say 'built' trans. This is where all my heart ache lies, since I was only pushing about 380 tq.

 

[donniekak]

Sure, torque does. But cyclical failure is also the culprit, fatigue failure. This is where the shotpeening helps out. For instance, Titanium as an example has a tensile strength of about 500-700 MPa on a static load test, but at 10 million cycles it drops to 140 MPa. Shot peening can improve the fatigue strength to about +30%. So, you can see the more cycles you have, the radically lower the failure point. This is where electro-polishing and/or shot-peening can help out with prevention of crack propagation.

Another culprit can be heat treat. Get the gears hot enough, I'm talking about localized temps right at the gear tooth interface and not bulk oil temps, and whatever heat treat process the gears went thru to increase the tensile strength of the base steel could get cooked right back out of it.

I've seen my gearsets taken apart, the gear wear is absolutely enormous on a built transmission due to the high gear stack preloads. Then toss in an ungodly amount of torque, and the thrust loads can create a ton of extra frictional forces that strips the gear face of material. On my stock intermediate shaft at 60,000 miles the thing looked like I pulled it out of the bag brand new, which I happily reused on my "built" tranny. The failed intermediate shaft off my built tranny had unbelievable amounts of surface wear.

Helical gears, high gear stack preloads, and high torque don't mix IMHO. Thats where the straight cut gears make sense. NO gearstack preloads, NO thrust forces, much much lower sliding frictional forces. Just pressure forces on the gear face to deal with.

I don't know about you, but on my race transmissions, i cant turn the input shaft by hand when in gear, the preloads are so high. This and shot peening have been keeping my 3rd gear from de-toothing, but my bearings are shot, and start to rattle after about 10k.