This is one the few things shying me away from building my dsm up first rather than my z. Not just the tranny, but the whole drivetrain on these cars are weak as s***, where as the entire drivetrain on my z from the tranny to the hubs in the back is pretty well indestructible(there's been like 5 reports of broken transmissions ever) and people over a 1k hp are still using a stock drivetrain (aside from clutch). I say someone musters up the money and work to make a dsm rwd and swap in a different trans all together so we can rid of these problems. Of course im just talking out my a** but it would be cool.
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Make sure you get a bunch of cores. You will be breaking them while learning. That's okay as you will get better as you go along. It's all part of the deal and could be fun!
Jack
Id have to disagree, If you do your research, take your time, nobody should have any problems. My first tranny I rebuilt was a twin countershaft eaton fuller in college a couple years ago for my teachers friend. Still goin till this day .
Btw Jack, I will be needing some parts from you here soon. my center diff blew (stock), put a quarter size hole in my case
I don't know about everyone else but my car has a bone stock 92 AWD tranny in it....even the open center diff! While the trannies are not bulletproof, you can still make some power with them.
I made 579 and 476 on a 2.3l in my 2g. My dogbox race trans held up to the abuse. I then parted out my car and sold the tranny to a friend of mine with a 2.4l. I dont remember the tq numbers but he made 615hp. The tranny handled the abuse just fine.
Dogbox gets all of my drivetrain business as I have never been let down in the dsm world or the evo world at this point.
The issues with our trannies isn't how much power can they take as they can take a good deal, its how long they can take this increased power. As people have said, there is only so much you can do with a stock style gear, no matter what treatment you do to it. Eventually if your making a good amount of torque, you will hurt the tranny, the questions is just how long before this happens. Mitsu rates the stock DSM gears at something like 250 ft/lbs. This obviously isn't their max holding ability but more the rated power they can continusiously take & last (exactly how long, not sure). Now step up to the evoIII gears & their still only rated at 375 ft/lbs. If your making 500+ ft/lbs, their eventually going to fail. Check out our gearset vs a Supra & you'll easily be able to see why we have issues....
If your making big power & you want a tranny that will last, the answer is plain & simple, get a dogbox.
Personally I run a TRE top of the line, stage 3. I went with Jon because he does alot of additional "detailing", which I saw in person.
Check out our gearset vs a Supra & you'll easily be able to see why we have issues....
I found these on a DsmTalk thread
The gears were never intended for high power. As said there are many improvements that can be made to improve the torque capabilities. I recently had to take my tranny apart to fix a broken 3rd fork and rail. It was surprisingly easy and I would not hesitate to buy a press and do a complete rebuild/improve if needed.
I did have a question and called the big three(shep,tre,jack) and Shep himself answered the phone after one ring. I have heard all of them do great work, but i'm just a stubborn bastard and insist on doing things myself I also don't have $2k spare to spend on a badass tranny
Autos seem to be the way to go now when in the HP range the OP is looking at. I totally agree that you are going to break them eventually on a helical trans. It gets expensive running that kind of HP as things can break at any time, but that's just all part of racing IMO. That's true with just about any vehicle though and if you look at what us DSMers pay for parts it's a real bargain compared to what others pay for just a synchro. I remember back when I used to have to pay over $300 for one synchro when rebuilding a Getrag unit! Ouch!
Jack
If this is true, why do people even spend 2 and 3 thousand dollars rebuilding their trannies? Why not just buy 4 or five used units and put them in when one of them break? I can get 5 used fwd trannies for 550.00 each. Will a built fwd tranny break eventually with over 500hp and if so why? It does not have the gear stress that a awd unit have! If so then I guess if you really need a tranny that will last for a good while and your car is fwd the route to go is shep dogbox awd and vce right?. I just broke my tranny, I knew it would happen with 470 ft lbs tq I am trying to figure which way to go at this point
Quote:
Originally Posted by toofast82
I found these on a DsmTalk thread
The gears were never intended for high power. As said there are many improvements that can be made to improve the torque capabilities. I recently had to take my tranny apart to fix a broken 3rd fork and rail. It was surprisingly easy and I would not hesitate to buy a press and do a complete rebuild/improve if needed.
I did have a question and called the big three(shep,tre,jack) and Shep himself answered the phone after one ring. I have heard all of them do great work, but i'm just a stubborn bastard and insist on doing things myself I also don't have $2k spare to spend on a badass tranny
I am eye to eye with you on this one I can't seem to get the other two on the phone either! but what did shep tell you?
Last edited by keltalon; 11-05-2009 at 05:06 AM.
Reason: Auto-merged with previous post to prevent "bumping"
Yeah i have some minor problems with my trans and i'm about to do a rebuild to about 400hp so i'd like something thats going to last, but if i'm only going to get an extra 3k out of a built trans, its just not worth it, i'd rather hit up Junkyards and get spares. I know (jack, since your one of the big three that is actually on these forums) that this is your business and all of this stuff does help the longevity of the trans, but for someone on a budget, is it really worth it?
Well, it depends on what your intentions with the car are.
If you want a junkyard transmission, you will get something that is completely unknown and pay for it.
If you want a transmission just to drive around to get to/from work, go get a junkyard transmission.
If you want a transmission that is properly rebuilt with new parts, that shifts great, and can be raced with, then go with any transmission buildup above an economy or stage 1 build.
Personally, I like streetability, and I only use 4-spider center diffs in my transmissions. I tried a welded center diff, and a spooled center diff; I didn't like how it reacted or handled. And with my power levels, I cannot afford to cheap out on a transmission, as it will last for a very short time and will require a rebuild then.
Keltalon - In your circumstance, being a 2G FWD with a pretty decent torque number, I would likely run a 2G AWD transmission swap with a spool or welded center diff and VCE, the late 91-early 92 3/4 hub and slider/gearset assembly (Heavy Duty 3/4 upgrade), and an upgraded front differential (LSD insert or Quaife). The gears and shafts are actually quite a bit stronger than 1G/2G FWD Transmissions. I would also run equal-length axles (AWD driver-side halfshaft and axle), and solid motor mounts (aluminum front/rear, poly sides).
It is either this, or you build up your 2G FWD transmission (which will break sooner or later). I am not saying that the AWD transmission is going to be the last one you install, but it will be the best one in the circumstance that you are FWD and need a beefier transmission than stock.
Buryurfear14- If you want something that is going to last, get a street buildup with new bearings, 4-spider center diff w/ torrington bearing, new synchros throughout, new reverse cone and wave spring, new 1/2 and 3/4 hub & slider assemblies, and new shift forks. If it is your original transmission, you *MAY* need to get the HD 3/4 gearset as they changed mid-year in 1992 to a weaker 3rd/4th hub and slider assembly (which has different gears, synchros, hub and slider, springs and keys than the earlier model -- late 1992-1999 have the same 3rd/4th assembly with larger synchros but a much weaker 3rd/4th assembly).
Personally, I think it is worth the price, as I have built and broken many, many transmissions. I have learned what works, and so have these other transmission rebuilders.
As a transmission rebuilder (myself and all the other guys), we are only here to provide you all with a service, help out the community, and provide as much information as possible so you make an intelligent decision and get the best quality product possible with the parts that are available. We are not getting rich off of transmission rebuilding by any means. If you want a reliable transmission that will last for a long time, and handle the power, go with a built automatic. A dogbox requires just as much, or more attention than a helical synchro transmission -- and maintenence is more expensive when you need it.
____________________________
Tim Zimmer
2.3L, BW475, AEM, etc.
Keltalon - [/B] In your circumstance, being a 2G FWD with a pretty decent torque number, I would likely run a 2G AWD transmission swap with a spool or welded center diff and VCE, the late 91-early 92 3/4 hub and slider/gearset assembly (Heavy Duty 3/4 upgrade), and an upgraded front differential (LSD insert or Quaife). The gears and shafts are actually quite a bit stronger than 1G/2G FWD Transmissions. I would also run equal-length axles (AWD driver-side halfshaft and axle), and solid motor mounts (aluminum front/rear, poly sides).
It is either this, or you build up your 2G FWD transmission (which will break sooner or later). I am not saying that the AWD transmission is going to be the last one you install, but it will be the best one in the circumstance that you are FWD and need a beefier transmission than stock.
I just located a 2g awd I will be picking it up. Thanks for info
If this is true, why do people even spend 2 and 3 thousand dollars rebuilding their trannies? Why not just buy 4 or five used units and put them in when one of them break? I can get 5 used fwd trannies for 550.00 each. Will a built fwd tranny break eventually with over 500hp and if so why? It does not have the gear stress that a awd unit have! If so then I guess if you really need a tranny that will last for a good while and your car is fwd the route to go is shep dogbox awd and vce right?. I just broke my tranny, I knew it would happen with 470 ft lbs tq I am trying to figure which way to go at this point
Because you will pop the old used units quickly. A built unit with 700hp going to it will not live forever, but you will get a couple of seasons out of it over breaking a trans every pass. In the long run, paying $550 a pop and constantly having to R&R the unit will cost you a lot more money.
Jack
Quote:
Originally Posted by buryurfear14
Yeah i have some minor problems with my trans and i'm about to do a rebuild to about 400hp so i'd like something thats going to last, but if i'm only going to get an extra 3k out of a built trans, its just not worth it, i'd rather hit up Junkyards and get spares. I know (jack, since your one of the big three that is actually on these forums) that this is your business and all of this stuff does help the longevity of the trans, but for someone on a budget, is it really worth it?
Yep, like I said in the previous post it is. It's embarrassing breaking at the track or always telling people your car is down. I like mine to keep going without worrying about it. You never know what you’re going to get with used stuff and the weak links are always in it no matter how many times you swap them. A built unit will always have the better stuff even if it won't live forever.
Most people that think they have a lot of HP though never break them. It is rare that I will see any of my customers break a gear no matter what the power. It happens, but I get very few of them.
Jack
Last edited by JackM; 11-05-2009 at 04:20 PM.
Reason: Auto-merged with previous post to prevent "bumping"
To add to Jack's point. Even a stage 1 aftermarket transmission ( basic stocker) is better than a used trans because it doesn't have 100,000 miles on it. Most of the high mile transmissions i get into have bad wear on the end of 3rd and 4th anyway, that much closer to a failure. Not to mention the wear on the spacers in the center diff allowing massive gear lash. The best upgrades to get are the center diff mods, 4 spider, or welded. I haven't sheared the teeth off of 3rd or 4th until i really put some power through one of these boxes. I think some of the worst things to happen to a dsm trans are 16g's and dsm link. Massive torque, boost off the line, and no lift to shift, all really bad shock loads.
Excellent. Thank you guys for responding back! Incase there was any confusion about my post, i just want to let you guys know in no way was i trying to say rebuilds were a rip off and you guys were just out to make money. I seriously apologize if it came out that way! I guess what I was trying to ask was, unless your running so much power that a stock tranny just wont cut it, is a BUILT transmission really necessary. That question has been answered though. Initially I intended to go with shep for a rebuild and I don't doubt that he's a great guy and puts out great work, but since Jack has taken the time to post in these forums i'll send my trans your way when it comes time. Thanks!
twicks69, what was it about the welded center diff that you didn't like? There isn' t really a large dsm community around my area so i haven't gotten a chance to drive different setups to know for myself. You seem very knowledgeable so your opinion, I think, would be worth something. Thanks!
twicks69, what was it about the welded center diff that you didn't like? There isn' t really a large dsm community around my area so i haven't gotten a chance to drive different setups to know for myself. You seem very knowledgeable so your opinion, I think, would be worth something. Thanks!
I don't like the binding up issues, and the extra drivetrain wear issues, and low-speed steering issues with running a welded differential. I also prefer the traction 60/40 as it is a bit easier on the drivetrain and I don't snap rear ends, transfer cases or rear axles. Upgraded front axles are cheap and easy to install.
I prefer to use an aftermarket cross-shaft in the center differential as well. The piece I use in all the transmissions I build with 4-spider center diffs is a hardened chromoly steel 2-post/4-spider cross-shaft with oiling grooves, and is substantially stronger than any other cross-shaft on the market currently. It is the only shaft that I haven't shattered, galled up, or had binding issues with over the years, along with being capable of handling over 1000HP/900TQ without failure.
I have used machined-down stock cross shafts, cryoed/shot-peened stock cross shafts, Shep's cross shafts, Jon at TRE's machined down cross shaft, Speed Design's 4-post cross shaft, and BM Trans' cross shaft. I have broken every one of them other than the Speed Design one -- which was not square and took out my spider gears, and trashed the housing, cross-shaft and pinion set.
The problem with machining down the stock cross shaft to accept 4 spider gears, is that it is the weak link in a center diff in the first place (other than the spider gear shims and pinion gear oiling shims), and likes to shatter with wheel hop or higher-than-stock power levels. Most rebuilders just machine down the stock cross shaft to accept the gears and it now has less material left on it for strength. There are a few guys that have machined up their own new 4-spider cross-shaft out of quality material that can handle the power, but getting the shaft perfectly machined square, and having some sort of oiling grooving is very important. The machining of the center diff case is also pretty darn important to have the tolerances correct.
Yeah, a 4-spider center differential does cost more than a welded diff, or center diff spool. The upside is that you have complete streetability, normal drivetrain wear associated with a stock transmission, and will enjoy your car driving in normal daily driving conditions. If you want a race-car only, then you can look at the welded diff if you like -- personally, I like a 9-second street car.
Don't get me wrong, the welded center diff is fine for some people, just not me.
____________________________
Tim Zimmer
2.3L, BW475, AEM, etc.
Well I just bought a brand new oem fwd transmission from a buddy of mine Md972017 I think I will use this one for a while and then maybe in the future go the built route. In the mean time I will install a wavtrac lsd to help with traction and maybe some 272 cams to bring down my torque numbers and raise hp numbers to help relieve some stress on the new unit. I gave him a fraction of the 2200.00 dollars he paid for it from the dealer
Of course im just talking out my a** but it would be cool.
? Why not just buy 4 or five used units and put them in when one of them break? I can get 5 used fwd trannies for 550.00 each. Will a built fwd tranny break eventually with over 500hp and if so why? It does not have the gear stress that a awd unit have! If so then I guess if you really need a tranny that will last for a good while and your car is fwd the route to go is shep dogbox awd and vce right?
. I just broke my tranny, I knew it would happen with 470 ft lbs tq
I am trying to figure which way to go at this point
