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Straight cut synchronized gear box!

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@keltalon which 3/4 hub/slider are you running? I see that the EvoIII hub/slider is obsolete…it’s my understanding that it is the one to have as it is forged. Does TRE have any left overs? The OEM DSM ones are cast and it’s my understanding that machining them down to accept dbbl synchros diminishes strength further. This would imply the still available unmodified/single synchro DSM small hub slider is superior in strength barring getting a hold of some new EvoIII ones or good used ones. I suppose this is just another common weak link but I raise this because it would suck to explode the 3/4 H&S and subsequently trash the PAR gearset and I am curious as to what TRE recommended and set you up with and what torque limit? I hope that the revised PAR gears are indeed stronger than the previous version too and you get some considerable miles/passes out of this setup. Subscribed.

The hub and slider is a very real concern, supplies are long gone for Evo stuff, and I've seen people fight over used Evo III units. I lucked out and found a brand new Evo/HD hub & slider in France, I'm hoping it never fails, or I may be SOL.
I don't think I've seen the hub and slider fail on Matthias' gears, or the previous PAR iteration. But since PAR is willing to re-engineer the kit, I doubt they would let an obsolete hub & slider sideline their product. They would come up with a solution.

Kel, I'm curious what happened to your last transmission, too. I had really high hopes for that thing. Is it still alive?
 
Is the hub and slider that fragile? I've never broken one or even seen one broken. Just hear horror storries. I mean I guess if your powershifting into 3rd or something. But set a decent NLTS RPM and don't use a clutch that holds 1000ft*lbs, and it's probably not an issue.

Also for the record, day 4 of waiting for a response to my price inquiry to TRE. It's really like 6 months since the first time I asked him, but I re asked friday.
 
PPG advised their dog box will last 80k miles on the street with oil change and direct shifting. I don't see why PAR can't last just as long. Case in point most sports bikes are all dog straight cut transmissions. They outlast their high revving motors. These are oem dog gears directly from the manufactures. These bikes see at least 10k rpm shifts. Small motors but the principal/useage is all the same. Dog gear is fine for street use. I'm sure It will even outlast my motor.


Uhh can I get a link to a dog box lasting 80K miles, thanks!
 
Uhh can I get a link to a dog box lasting 80K miles, thanks!
You can get that if you know how to drive it, and don't miss 2nd gear ever.

Expect regular service items to be 2nd gear and 1/2 slider on 99% of those that are raced or driven hard.
 
My liberty stuff seemed like it would have lasted 10k or more driving it in my small town stop and go/ having fun/ highway miles. Lot different if you just get on the highway and go, but they'd probably last a very very long time like that.
 
You can get that if you know how to drive it, and don't miss 2nd gear ever.

Expect regular service items to be 2nd gear and 1/2 slider on 99% of those that are raced or driven hard.

Can you explain that further, you say it will last 80K but you need to service it regularly, so which is it?

If it needs taken apart constantly and have the gears resurfaced regularly than the tranny doesn't last 80k miles. How long does the trans last before it has to be removed for XYZ.....that is the answer I am looking for.

And from my understanding shifting a dox bog wether at WOT or just normal shifting creates the same wear.
 
It will last as long as you take care of it. It is all up to the end user, along with your ability to actually drive, your power levels and your usage of the clutch.
 
I was visiting him we go back, just small talk about the company and the work doing with par, if I had more to share I would but I went to talk about parts for my trans and a friend. Nothing informative about the set up. I'm just following the thread, tre is about 10 minutes from me so it was nice to just see him hes quite busy.
 
It will last as long as you take care of it. It is all up to the end user, along with your ability to actually drive, your power levels and your usage of the clutch.

OK I'll give you two scenarios: 16g build mostly street driven with a few launches and the driver knows how to shift.

42r build with mostly street miles with a few launches and the driver knows how to shift.

SO how many miles does this thing last before needing serviced?
 
It will last as long as your bearings last then. Hub and sliders and bearings are wearable components over time. I know several people that were making very decent power, like 800+AWHP and had 8 years on their PPG dogboxes before needing to service them, with countless track passes.

Having a driver that knows how to shift as well as having a ignition cut, or rev retard, or using the clutch to take the load off of the transmission will make it last a very long time.

If you have a 16g car, you should be on a stock transmission if it's a street driven car. There is no need for an aftermarket gear set on a 16g unless you are trying to set records, or you are racing the car. A stock refreshed transmission can handle 400 WHP all day long with the big failure modes going to be a stock center diff (upper pinion gear friction welding the pinion washer to the cover, or the cross shaft breaking on a stock 2 spider diff), or the 3/4 hub and slider from abuse / overheating. Anything past that is from normal wear and tear, or excessive abuse (like broken shift forks or shift rail ends).

If you have a car making 600+AWHP and you are actually racing it and treating it not like a regular car, then you should be on a straight cut dogbox. Durability, and service life vs. the cost of the components is in your favor then. When you are breaking more than 1 transmission a season (I was breaking 4 or 5 built transmissions per season of street / track / dyno time for several years which typically cost around $3000-4000 per failure so it adds up), you are at the point of looking at budgeting for a straight cut dogbox simply for service life.

With the cost of OEM Mitsubishi parts being significantly higher than they were even 8 years ago; around a 150-200% increase in that period and they typically go up 5-10% every couple months; as well as a large portion of the transmission components being no longer available / discontinued worldwide, we have to bite the bullet and look at Liberty, PPG or PAR gearsets as a solution for component replacement / upgrading.

When you are looking at the cost of a basic comprehensive OEM rebuild starting out around $2000 or so for stock replacement parts, and working up to around $3500, BEFORE options like an aftermarket front diff or output shaft or bearing plate or surface treatments, etc. With options you can easily get into the $6000+ range on a gearbox with a stock gearset. With face plating as an option on the stock gearset to get it to shift faster, it might be cheap to do it to a free used gearset and about $1000 later you have some modified stock used parts done up to shift faster. When you are doing it to a brand new gearset as well as surface treatments, and diff upgrades, etc. It starts around $4000 and goes up from there.

With a PPG or PAR gearset, you are starting around the $4500-6000 range for a 9310 hardened steel straight cut gearset either with dog engagement or synchronized gears for a 1/2/3/4 gearset. They are considerably more durable for the gear teeth and shafts. The engagement dogs on the gears CAN get worn over time from regular usage, or they can get hurt from a hard high-rpm mis-shift. If you are at the track and completely miss 2nd gear with a hard mis-shift you will easily hurt the gear in a couple screw-ups. Nature of the beast. At the same time, you can race the car 6, 7, 8, 9, 10 years of good times before needing a refresh. Just like a clutch, it will last as long as the end user takes care of it. As for associated costs, you still have to modify the transmission case to accept the new gearset, and that also refers to modification to shift forks, shift rails, 5th gear cover, oil guides, input snout (TOB sleeve), shift selector modifcation, etc. And if you are starting out with a 1989-1991.5 transmission there is even more conversion you need to do because of the early style shift lever / selector components being very weak. You can easily have another $1000-2000 in parts for assembly between bearings, differential modification (if you choose to do a 4-spider center diff you will need to machine components as well as get a proper cross-shaft, additional pinion gearset, shims, torrington bearing and thrust washers, machine the diff cover, machine the diff housing, etc.). Then, you have upgrade options like the 300m output shaft (which really is a must with a spooled center diff race car; you will kill output shafts over time), a billet aluminum bearing plate (the stock one likes to deflect and say bye bye to your gearset), an upgraded front differential (spool front, phantom grip / rip grip mod, Quaife LSD or KAAZ LSD or Ralliart LSD differentials) Then you have labor cost. Are you doing it yourself or are you having a professional do it? That isn't free. So you are realistically looking at ~$6000 for bare bones, ~$7500 for a proper build, and around $10,000 fully optioned out.

As for myself, well, I broke other shops built transmissions for several years before saying screw it, and building them myself to learn. I broke around 23 or 24 in less than 7 years with power levels anywhere from 400AWHP-800AWHP, and I have gone through like 5 in the last 10 years with power levels anywhere from 700AWHP-1000AWHP. I also have taken it a bit easier on the car and I race less.

I have 3 or 4 years on my face plated dogbox in my car, and it is no slouch for power and sees almost all street time when I drive it. I have had zero issues with mine, and I typically am driving around the car at the 740-750 AWHP range on the street on waste gate spring. My transmission is an Evo 1 1st/2nd , DSM ratio 3rd/4th, Evo 3 5th gearset, 4-spider center differential, Adelia Magic Clutch Type Coupler (replaces viscous coupler), KAAZ Super-Q clutch type LSD front differential, Boostin 300m output shaft, and the entire gearset is deburred / detailed, shot peened and REM treated with steel Evo 3 shift forks and forged steel Evo 3 shift rails.

Though it has performed well at this power level for the duration it has seen of street time, I am still changing over to a PPG dogbox 1/2/3/4 gearset with Evo 3 5th gearset, spool center diff, Boostin 300m output shaft, Kaaz Super-Q LSD front diff, and Boostin billet bearing plate. This will be the upcoming race trans I use for the remaining life of the car.

I could have bought easily 8 or 9 PPG dogboxes if I had started out going directly to one back in 2003-2004 or so when I started breaking gearboxes. Heck, PPG gearsets were dirt cheap way back when. Their prices have gone up a bit in the last couple years, but so has everything else gone up in price; just part of life.

Either way, a dogbox isn't for everyone, but it sure darn well beats breaking 3 race transmissions in a season.
 
Uhh can I get a link to a dog box lasting 80K miles, thanks!

Here is PPG phone number. Contact them your self and question their product. Ask them why they make these claims and report back to us.

P: +61 8 8285 2933
 
Transmission arrive and ready to go in. T.R.E special.

@keltalon what ever happened to the indistructable WPC treated and cryo'd Evo 1 GSR box you had?
I still have it.

Keltalon I have been waiting to see you back in action . can't wait to here more.
Thanks Lou. I am working on 3 projects at one time. The Twin turbo G35 has been eating my pockets almost finished with the engine. I haven't given much attention to eclipse since last sept when someone tried to steal the car a the ga 1/2 mile event but now I have turned my attention back to the car. Experimenting with these custom gears and better ratios.

[/QUOTE]
@keltalon which 3/4 hub/slider are you running? I see that the EvoIII hub/slider is obsolete…it’s my understanding that it is the one to have as it is forged. Does TRE have any left overs? The OEM DSM ones are cast and it’s my understanding that machining them down to accept dbbl synchros diminishes strength further. This would imply the still available unmodified/single synchro DSM small hub slider is superior in strength barring getting a hold of some new EvoIII ones or good used ones. I suppose this is just another common weak link but I raise this because it would suck to explode the 3/4 H&S and subsequently trash the PAR gearset and I am curious as to what TRE recommended and set you up with and what torque limit? I hope that the revised PAR gears are indeed stronger than the previous version too and you get some considerable miles/passes out of this setup. Subscribed.[/QUOTE]





I know Jon had a few of these left but to be honest I can't say but I'll find out.
 

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IMO to complete a high end build like this I think getting a hold of the forged Evo III hub/slider(s), used if need be, is prudent. In this context, the trans failure point would likely shift from gear teeth to the 3/4 hub/slider. A big increase in safe torque capacity via stronger gears would be significantly diminished without addressing this key area and worse yet a failure would likely destroy the whole gearset investment. IIRC, keltalons car puts down ~600+ WTQ. IIRC, TMZ blew up a H/S at around 600 whp trashing the old PAR set. Usually I strip teeth but Ive had a OEM 3/4 small “HD” H/S explode on me destroying a new professionally assembled OEM gearset w/treatments in ~3k miles at ~500TQ, no missed shifts. Is this H/S reliable at 500ft/lbs and street use? Maybe it was a fluke but it gives me pause and similar failures have been documented on the various forums. I deduce this would likely be more pronounced and therefore crucial especially as gear strength and TQ increases.

Now there are three hub/slider versions worth discussing—as there is already a consensus with the fragile large hub failing around 350 Tq. This leaves; OEM small H/S, OEM small H/S modified for double synchros and the Evo III H/S. The only variant I have never seen broken is the Evo III H/S which happens to be forged—maybe because it is much stronger or rare or both. I presume there may be some advantage in cast metal generally having less thermal expansion than forged as it relates to keeping its shape/clearances more as it gets hot. Alloy comes into play here but some alluded to heat being a failure mode and I’m not sure what to make of that. Considering this part transfers the torque supplied by the engine from the shaft to say either 3 or 4th gear, it is plainly under a lot of stress when meshed together. I have heard that machining down the small H/S weakens it, but by a noteworthy amount that shows up in rate of recurrence when compared to std. OEM I am left to wonder. The PAR synchro set will surely be limited by these particular H/S combinations and understanding their respective limits would better avoid a ticking time bomb scenario.

@twicks69 and anyone else that may have insight; what is your thought/experience on the safe (and differing) TQ capacity on these three H/S variants? At what TQ do failures (non driver error related) start showing up? Any other relevant info is appreciated.
 
There is technically a 4th variant - the Evo 1 uses the large diameter hub, but is forged/broached. It might buy some safety over the 93-99 DSM unit, but not much. Also curious to hear about some failures.
 
Regarding the hub and sliders,

For hubs,
I typically see the stock 1990-1992.5 style small synchro hub break/crack around 600ft/lb tq or with excessive abuse at a little lower power levels. The stock 1992.6-1999 style large synchro hub typically would break around 350-450ft/lb tq on the street / track or dyno. I have broken several personally.

The Evo 1 and Evo 2/3 forged / broached hubs are considerably stronger than any of the cheap powdered metal DSM hubs. I would assume that an accountant with Plymouth/Eagle/Chrysler was pinching savings on material costs when you are manufacturing a few million of the parts for the entire DSM platform in comparison to the Japanese making a high quality product for their Mitsubishi Evo 1/2/3 platforms. That is the most realistic answer why we have crappy material used for the DSM components. It came down to cost.

Of course, the Evo 1 and Evo 2/3 3rd/4th forged / broached hub and sliders are completely discontinued.

I have not seen any failures personally of an Evo 1 or Evo 2/3 HUB. Sure, I have seen sliders fail or overheat / bind, but not the hub failing.

As for the MD747646 OEM "HD" 1991.6-1992.5 thick flanged powdered metal DSM 3rd/4th hub and slider that accepts the small diameter synchros or the Evo 2/3 double synchros when modified, well, I have seen numerous failures at high power levels. With modification to the hub for accepting double synchros, you have to machine down a little spot for additional clearance so you don't jam the double synchros in them, and the key importance is put in to machining the radius, and then shot peening and surface treating the hub after machinework. I have seen several from Jack that were done and there was no chamfer left on the clearanced area and it would be exactly where the hub would fail, splitting the interior splined portion of the hub that presses onto the input shaft clean off from the rest of the hub. Jon @ TRE does a great job with his machining and shot peening of the hub and there is still a decent chamfer on the machined spot and it clears the Evo 2/3 double synchros properly. He also uses nice and strong hub and slider springs that have a different tang style than the DSM OEM spring tang design. It results in a much lower likelyhood of it popping out of the key, and pretty much stops the spring from breaking off the tang.

For sliders,

There are like 5 designs of sliders used. The thicker flange 1990-1991.5 style with the square face side on 3rd gear side which uses the MD742777 large face keys and small diameter springs (MD738050 or MD742441), and then the 1991.6-1992.5 style with tapered faces on both sides and uses smaller MD748663 keys, and same springs as above -- MD747646; then the MD746826 which is a thick flange hub with the MD742777 large face keys and same springs as above. Those are all the small diameter style sliders. For the large diameter sliders, there were a few part numbers that were used, all used the MD748663 small face keys and large diameter MD742445 springs (same style as 1st/2nd hub and slider). The flange on the MD747647 slider is a bit beefier than the later MD749416 hub and slider; I have seen and used both in the past, and the MD747647 slider does a bit better with surviving under power before it breaks / overheats and jams on the hub or breaks into pieces. The MD749416 typically broke in the 350-450ft/lb torque range, and I pushed them up to around 550tq on the dyno and have broken them on the dyno too LOL.

The sliders for the Evo 1 and Evo 2/3 hub and slider assemblies are very similar in slider construction. The Evo 1 MD747651 3rd/4th large diameter synchro assembly has one identification mark on the slider OD, and a thick/ squared edge flange face on one side, and it uses shallow face MD742419 style synchros with small face MD748663 keys. I have never seen the hub fail, and I think I have only seen 1 slider bind up from super overheating it (3rd/4th gear pulls without cool down). The Evo 2/3 MD747378 hub and slider is designed to be used with MD742777 large face keys, MD738050 or MD742441 springs, and then either MD744782 single synchros or MD747255 Evo 2/3 double synchros. It has a thick/ squared edge flange face on one side with two identification marks on the slider OD. The slider is the same style as the MD746826 DSM hub and slider; difference is the DSM version has one identification mark on it.

The DSM 3rd/4th hub and slider is the biggest weakness in a high power application when we are discussing gearsets in general. They like to break the hub or crack the hub from abuse or power levels, and the slider likes to break from abuse or power levels, or warp and bind up on the slider from heat.

Best way to keep the part alive the longest? Dyno at low boost and power levels, do not do a ton of street pulls, don't shift like a gorilla. Having a good gear oil will help, having an oil cooler and high capacity pump with a well designed spray bar or inlet/outlets on the transmission will definitely help.

The new version PAR gearset is a very nice piece, but we are still relying on the OEM Mitsubishi hub and slider which will be the failure point from heat or abuse. This is the reason why I prefer face plated gearsets or dogbox gearsets. More durable sliders and much thicker hubs. The Liberty face plated hub and slider is easily double the thickness hub and a very durable slider. The PPG hub and slider is also extremely durable and well made. The PAR old version was not so strong; I don't know if Haysam has changed the 3/4 slider design since 2014 which is the last time we ran their dogbox in Andrew's WTAC car. We exploded the slider and it killed our entire gearset.

I think that's enough time touching on that topic.
 
My trans was done by t.r.e and it's still going with no problems .
We'll I beat the crap out the fwd it was running strong when I decided to swap to awd. I built the awd myself using the small 3/4 hub slider wpc treatment and all . The awd trans I built is good as far as gears and hub slider but I started feeling some vibration that I couldn't get rid of so I broke the tranny down . For Two reasons I got tired of the 3.909 very quickly and second the vibration. Come to find out after Jon tore down the center diff the cross shaft was galled pretty badly causing the vibration. Never broke a gear or hub. I had the Center diff machined locally to accept the 4 spider Jon said it was machined wrong causing the damages. I'll post a video later. I am very confident in the buikb and cant wait to beat on it.

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