2G Building a stronger 5 speed transmission

[Canadian_CD9A]

MD747255 is obsolete?!?!

 

[twicks69]

Yuppers. There are a couple in Japan and UAE, none in USA. Obsolete in USA Mitsubishi catalog now. Same goes for Evo 3 3rd and 4th gears and the Evo 3 3rd/4th shift rail.

 

[Canadian_CD9A]

Arg, gross. MD747250 looks like it’s still available from Japan for those who need it, but adding to cart on those synchros from UAE, just in case

 

[CrackedDSM]

Heads up that the double synchro for the PAR 3rd/4th (which is also used on the Evo 2/3 3rd/4th gearset) is obsolete. The 3/4 hub and slider you would have to purchase off Ebay from this vendor - https://www.ebay.com/sch/i.html?_dk...=reasonablypricedparts&_oac=1&_nkw=mitsubishi

You would use your OEM 1st and 4th and 5th needle bearing sleeves, with a 2-hole 3/4 shift rail. If you are running a 90-91.5 trans with the early style shift selector assembly, then you have to use your factory rails (which are obsolete) that match the early style shift selector tab; if you are using a 1991.6-1999 style transmission, then you need to use either an Evo 2/3 3rd/4th shift rail that is clearanced to fit (obsolete), or a 1991.6-1992.5 style 3rd/4th shift rail for the 2-hole shift forks (also obsolete). The 1992.6-1999 3rd/4th shift rail does not have the correct shift fork roll pin location, so you would either have to custom fixture and drill it to accomodate or find the correct shift rail. Unfortunately, ALL shift rails are obsolete now.

The 1/2 hub and slider is still around currently through Mitsubishi; MD749414. The 1/2 and 3/4 and 5/R hub and slider springs and keys are still available. You would need the revised 3/4 hub and slider keys - 3x MD748663 and then 2x MD742441 springs. The 1/2 hub and slider uses 3x MD742775 keys and depending on which 1st/2nd synchros you are using (the thick 1st single synchro cannot clear two springs on that side of the hub and slider; but if you are using a shallow 1st synchro or a double synchro on that side, you can run two springs on both sides). The springs are MD742445, in stock form it would take 1 per side. If you are running double synchros on both 1st and 2nd, then you can run 2x springs per side.

As well, if you are doing a 4-spider center diff, then special machinework is needed to fit a 4 spider cross shaft in it at the proper setup height, along with machining a GOOD center diff cover (obsolete), and then use good shape upper and lower pinion gears (obsolete), and then 4 spider gears (OEM are obsolete, but NEAT gearbox has made some and is selling them - http://neatgearboxes.com.au/). As well, if I recall, PAR does their center diff housing with a 90 style lower pinion oiling washer, which is the same as the PPG center diff style; of course, those shims are all obsolete too. I was using MR954819 front diff pinion gear oiling washer shim set to fit the lower pinion gear in the center diff (also obsolete now). The upper, I would have the cover machined to accomodate a Torrington bearing (McMaster-Carr - https://www.mcmaster.com/5909K38/) with two 0.032" thrust washers (McMaster-Carr - https://www.mcmaster.com/5909K52/), and set it up for around 0.008-0.010" endplay. If I recall, is in the 0.104-0.110" cut range. I had a bunch of covers cut down at different increments so that I could adjust the cover to fit the gearset setup variation. The spider gear washers are in limited quantities, you can only fit a single washer per spider gear in the PPG and PAR housing, so you would need 4x MD737658 spider washers. I do still sell my heat treated chromoly steel 4-spider cross shaft, but currently only have a handful of them left. It needs a bit taken off the posts to have flats for it to sit at the correct height in the housing, but won't be an issue for strength, it is in the seating area, not the friction area of the spider gears.

You will also need to likely adjust the shift rail detent ranges, and clearance the shift selector cage to extend the throw of the selector tab if you are not getting complete engagement during setup. Typically though, it is much more of an issue when working on the dogbox version of the gearset.

*Facepalm* Well, shit. Guess when/if this trans grenades I'll go Auto. Lol. Blarg. Figures I get into the m/t game when parts are quickly Thanos-snap fading away in the wind.


So in order to use your 4-spider cross-shafts @twicks69 , they need some machining to work with normal/non-PAR gearsets? I don't know if my trans has a 4-spider, but I'm gonna plan as if it doesn't. But those are hard to find too apparently.

 

[twicks69]

The cross shaft drops in with no modification into a stock style center diff housing that is machined to accept a 4 spider setup. It needs flats on one side of the shaft to fit in PPG and PAR diff housings.

 

[Canadian_CD9A]

Tim, on the subject of obsolete Mitsu stuff that they really need to make again - any solutions for a MB160498 equivalent? (Internal tooth diff spring plate)

 

[twicks69]

God, I had a bunch of new clutch type diff parts at the shop before the fire, they have been obsolete for a while.

Mitsu will not make anything for us. Period. We have seen that for the last 15 years.

 

[Canadian_CD9A]

They don't make things we need, anyway. I ordered a new handbrake lever for my Evo and it arrived with a 2020 build date stamp on it, and they still have the plastic dash trim (around the head unit/HVAC/vents) in production for some reason. Same with roof rain gutters - obsolete and unobtainable worldwide for years, but I went to my local Mitsu dealer last year and they had access to 10 sets out of the blue. Just about everything I needed for exterior trim for my car was in stock in Japan, but damned if they'll make drivetrain parts. Those MB160498s are a pain, apparently the STi & Nismo R160 guys robbed them all. I need a pair to rebuild the worst Ralliart front LSD on earth.

 

[curt-s]

Ugh
Something tells me I bought back into the wrong platform last year... between nostalgia and fulfilling 'the dream' I think I'm scrooooed.

 

[twicks69]

This was writing on the wall for many years. It is not something that happened overnight. The only thing that has happened overnight are people asking friggen GOLD for their old used parts. I used to pay $50-100 for 1G AWD 5 speeds, $100-250 for 2G AWD 5 speeds, $50-75/good tcase, maybe up to $125 for a good 2gb tcase. Apex'i Super-AFC was like $100-125 used for 20 years, now they go for $200-250.... like umm what?? .

 

[1cleangsx]

So we basically have 3 options. Stay low power and have a stock trans refreshed, or go auto/PPG for power? That sucks about all the obsolete OEM parts that are required for the PAR synchromesh, that’s the next gear set I was planning on, looks like it’ll be PPG .

 

[twicks69]

You need plenty of parts for a PPG also that are obsolete, good times. But yeah, PPG is the only effective solution.

 

[avaien]

Go show your support!
https://www.dsmtuners.com/threads/bigger-stronger-w5m33-gears.544932/

 

[jakk220]

For all of those wanting these back when this post was made, it's finally a possibility. Make the purchase if you can so we can get these parts readily available.

https://www.dsmtuners.com/threads/group-buy-stronger-5-speed-gears.545357/

 

[Ludachris]

I deleted a few posts to prevent this from getting too far off topic. Sorry guys. Don't take it personal.

 

[Jon82567]

What goes into building the stock transmission stronger; it’s a question I’m sure many people have asked but most haven’t had answered other than the standard “buy better parts” answer. Stronger shift forks, upgraded gear sets and other parts that are extremely expensive through aftermarket businesses. What about the DIY guys , like myself, that are interested in learning to build one themselves by sourcing the correct parts from reputable sources? The best place to start figuring out what the process is for me is to search and ask questions on here since I know I always either find what I’m looking for or you guys point me in the right direction. In the long run I’m not sure if it’d be cheaper to just buy a stage 2-3 trans from somewhere or a used(I usually don’t see many but they’re usually $$$) or build a similar stage trans myself. Figuring out which parts that need to be upgraded is part of the learning process which others have learned through trial and error which helps others. I’m hoping that those who’ve built or are in the process of building a better and stronger transmission will share what there’re learning or what they’ already learned here on Tuners. At my age I’ve found myself focused on my DSM which may or may not be a good thing.

Here is an option that is cheapish fairly easy to install especially if you have an aftermarket bumper. Requires front mont turbo. It will make 3/4 last longer on highway pulls. Put a transmission cooler on your ride. Inlet hose goes in your drain plug outlet goes on your fill line. The cooler mounts where your factory intercooler goes. You can’t run any old pump you need on for the gear fluid your running. They have kits for semi trucks, and off-road vehicles (knob tire or dune trucks) you will also need a thermo switch you don’t want the pump running till it’s at operating temps. This will also keep straight cut gears alive a lot longer… helical gears are cut that way to reduce heat and noise. It’s a lot easier aftermarket. It’s also VERY useful if you like canyon runs riding in 3rd/4th or even 2nd apexing turns will overheat your gearbox a lot.

 

[babyviper]

Here is an option that is cheapish fairly easy to install especially if you have an aftermarket bumper. Requires front mont turbo. It will make 3/4 last longer on highway pulls. Put a transmission cooler on your ride. Inlet hose goes in your drain plug outlet goes on your fill line. The cooler mounts where your factory intercooler goes. You can’t run any old pump you need on for the gear fluid your running. They have kits for semi trucks, and off-road vehicles (knob tire or dune trucks) you will also need a thermo switch you don’t want the pump running till it’s at operating temps. This will also keep straight cut gears alive a lot longer… helical gears are cut that way to reduce heat and noise. It’s a lot easier aftermarket. It’s also VERY useful if you like canyon runs riding in 3rd/4th or even 2nd apexing turns will overheat your gearbox a lot.

There's a few write-ups on this. The one linked below is probably one of the best.

https://www.dsmtuners.com/threads/transmission-cooling.434313/

 

[Jon82567]

There's a few write-ups on this. The one linked below is probably one of the best.

https://www.dsmtuners.com/threads/transmission-cooling.434313/

wow one heck of a setup. I’m planning ruining a 97+ turbo auto transmission cooler with shroud bent with a heat gun to clear the turbo pipe. Differential cooler pump for 4x4 hose and barbed connectors on the fill and drain. Had a similar setup on my Trans Am the T-56 runs atf and it was the difference of burnt fluid coming out on a change to nice red and NOTICEABLY better shifts T-56 has clutch syncros