Transmission blown... Again...

[_Madman_]

I can no longer stand it... It's pathetic, it's the 6th time the transmission on my FWD DSM needs a rebuild

First was the OEM diff which exploded into pieces. Next the intermediate shaft exploded ruining almost everything inside the gearbox.

Got a new gearbox, it needed bearing replacement after just few months of use. Then I shredded the tooth off the second gear, next it required bearing replacement and syncro replacement on most gears...

And now, after some slippage of the front wheels, there is a clicking sound even in neutral if clutch is engaged...

It feels as if those trannies are made out of rusted scrap metal

 

[bryanwheat]

I can no longer stand it... It's pathetic, it's the 6th time the transmission on my FWD DSM needs a rebuild

First was the OEM diff which exploded into pieces. Next the intermediate shaft exploded ruining almost everything inside the gearbox.

Got a new gearbox, it needed bearing replacement after just few months of use. Then I shredded the tooth off the second gear, next it required bearing replacement and syncro replacement on most gears...

And now, after some slippage of the front wheels, there is a clicking sound even in neutral if clutch is engaged...

It feels as if those trannies are made out of rusted scrap metal

What kind of power are you putting thru it? They are actually pretty durable. Sounds like who ever is doing the work on the transmission is not assembling it correctly.

 

[_Madman_]

What kind of power are you putting thru it? They are actually pretty durable. Sounds like who ever is doing the work on the transmission is not assembling it correctly.

Probably around 280 hp at crank...

First was OEM tranny, the second is a rebuild, double syncs, forks, Quaife and stuff, which was later rebuilt here locally too.

I am driving it pretty hard, but still... It's not like it's 500hp on wheels and on slicks...

 

[bryanwheat]

Sounds like who ever is rebuilding them is not qualified to do such. You should easily get get 50k+ miles out of a transmission with those power levels.

 

[T is for TURBO]

Sounds like who ever is rebuilding them is not qualified to do such. You should easily get get 50k+ miles out of a transmission with those power levels.

I agree... Or you are really, really bad at driving stick.

 

[Archer Fabrications]

holy crap only 280 and breaking trannys eh? what fluid was being ran in there? were all the shafts greased before sticking them on the block? that blows man. i just installed my shep stage 3 after granading my center diff now i got the 4 spyder. but i blew mine at around 400HP and a few launches and 3rd gear pulls

 

[_Madman_]

The fluid is something dealers use for Evos, Castrol MT something, I need to look it up.

Fluid availability is pretty bad here.

Concerning repairs, the guy who does this have been rebuilding Mitsu trannies for a very long time, 10+ years, so I have little reason to doubt. Moreover, I don't even have any alternatives.

And I cannot imagine what can be done wrong when rebuilding a tranny. Even setting the preloads is not necessary if only syncros or bearings are changed as far as I understand. So it's a straight bolt-on, isn't it?

Is there anything during the process that could make them more fragile?

Concerning driving style, I have been driving only MT cars for almost 10 years, without any clutch issues or anything, I don't grind gears, and I heel and toe revmatch, and use double clutching when skipping gears.

I do drive the car very hard though. Breaking before turns is always heel and toe revmatch + brakes, 3rd -ht->2nd@~6500, brakes, -ht->1st@6000, release brakes, acceleration without slipping the wheels, but near traction limits, upshifts in high RPMs.

When intermediate axle exploded on the 1st tranny, and also today, it was a little damp, the road was wet, I accelerated near traction limit, and I think the tires were slipping-gripping-slipping-gripping for a short moment, after which the ticking sound appeared (missing teeth on one or more gears the first time, and I think this time as well).

The car does tend to wheelhop in damp weather a little... Not much in dry weather though.

 

[lowell]

You should definitely be setting the bearing preloads any time the trans is open. Were any of the gear teeth deburred? Wheel hop will break parts for sure, so it would be worthwhile to eliminate it.

 

[_Madman_]

The tranny will be opened tomorrow. No idea what's inside right now...

What are the preload values then? As far as I know Shep and John uses higher than OEM, no?

 

[Archer Fabrications]

The tranny will be opened tomorrow. No idea what's inside right now...

What are the preload values then? As far as I know Shep and John uses higher than OEM, no?

shep is john. you mean jacks? there is a thread in here with jack talking about that stuff and i even believe a video. all i know is you should AT LEAST be running MT-90 is a low HP dsm.

 

[_Madman_]

Does anyone know which symptoms I should check in the tranny tomorrow? To figure out what might be the cause.

Or is it simply a wheelhop?

 

[Archer Fabrications]

yeah when you drain the fluid, if it has flakes, rebuild it again. when you crack it open, if you find chunks.. well it could be a sleeve or a 3-4 hub. what i got a clicking sound when i reved my motor in neutral, and would go away when clutch was pushed in. soon thereafter granaded the center diff and 3rd 4th sleeve/slider.

 

[mnim15]

Have you inspected the transmission mounts? I know someone who went through 3 transmissions in their FWD, noticed the rear mount was cracked across. May be coincidental, but after replacing that it still has the same transmission in it...

 

[_Madman_]

Have you inspected the transmission mounts?

Mounts usually help a whole lot, but as it stands I have 2x full poly mounts and 2x inserts IIRC. The poly kit.

This has almost removed the dry surface wheelhop, but in a damp weather the pesky jumping still persists

 

[Archer Fabrications]

Mounts usually help a whole lot, but as it stands I have 2x full poly mounts and 2x inserts IIRC. The poly kit.

This has almost removed the dry surface wheelhop, but in a damp weather the pesky jumping still persists

Are you sure you don't have a welded center diff? or have a viscus coupling installed or something? if your getting wheel hop one of your diffs is effed up

 

[turboglenn]

one tyhing going unmentioned is how the trannies are treated, I've blown a few myself and the first was at well udner 400hp and above 325 (was a work in porogress at the time) i went TRE for FWD and it lasted until i sold it and then blew apart in keltalon's car, (but there's the unknown about maybe fed ex droipping and cracking the case as well, because the trans didn't have many miles on it maybe 30k and the car hadn't been raced because we have noi track and my injuries started eeping me from anything like that about the same time i got the trans)

Well, now i'm AWD, blew one on the dyno a while back (2 months or so) at 522WHP, had NO MONEY, rebuilt it myslef with guidance form TMZ and a few tools, then that one had an issue from my "helper" dropping a trans mount nut in the speedo sensor hole) so it came out again, i rebuilt and shimmed it AGAIN and put it back in, since then i've not pushed 500+ but keep it around the same tune as i had wehen i made 482hp, and haven't had an issue yet.. I granny shift, i don't "launch" hard, I will gt the car to a 1mph roll then ride the cluitch in at most.. but it breaks all 4 wheels lose on cool nights and dry pavement in first gear, spins partially through second and pulls like an angry gorrilla and the parts inside are all used OEM stuff cause that's all i had money for.. now i've seen people with 300hpo beat the car with flat shifts, hard clutch dumps and mopre and can't keep a built tranny in to save them, it's a lot to do with how you drive really, because 280whp isn't enough to even scare a DSM trans whenm driven with some thought to the damage you "could" do

gotta run, but i hope you get one to hold soon, I know howq it can be being that i had to change mine (at least pull and re install it) 5 times in one month here when i blew the first one on the dyno at 522

 

[bryanwheat]

Are you sure you don't have a welded center diff? or have a viscus coupling installed or something? if your getting wheel hop one of your diffs is effed up

He doesn't have a center diff or viscous coupler. It is a fwd transmission.

 

[Archer Fabrications]

damnit. I'm on tappatalk

 

[_Madman_]

It has Quaife LSD inside, which helps a lot overall. But still, I do get wheelhop on damp surfaces.

I will post back with what hat happened when the tranny is open.

 

[_Madman_]

It's the second gear, two teeth are chipped off.

Previous breakage was 2nd gear as well, that time it was only one tooth.

Are there any alternatives that can be used to avoid this in future?