JDM box with LSD

Carolyn · July 27, 2019, 13:44

A 'heads up' for those of you who like to track your car or do a bit of B road 'scratching'.

Dean at Rutland MR2 has just broken an MR S with a JDM five-speed box with factory LSD. More hens' teeth!!

Dev · July 27, 2019, 14:54

That doesn't surprise me. The transmission for our cars are weak particularly the third gear and the input and output bearings. The synchronizers are also sensitive to abuse and fluid that is corrosive to yellow metals.

Despite all of this I have no problem with my transmission and prefer it to be the way which is meant for street use for a momentum car. The other option is adding more weight and cost so there is a tradeoff. There are many factory transmission from the likes of Getrag that also fail and don't hold up either when abused.

The best thing to do in a situation like this were racing is required is to have a spare transmissions as the cost of admission.

When someone is selling a car that has been raced I generally pass because it can put many years on a car.

shnazzle · July 27, 2019, 15:18

Dev, I thibk Carolyn means Dean is breaking a car that has this transmission

The car's gone, the transmission is fine. And it's a great transmission indeed! Not great on motorways but definitely noticeably feistier on the b-roads. I really enjoyed driving Carolyn's

1979scotte · July 27, 2019, 15:49

We really don't speak the same language do we 😂

Carolyn · July 27, 2019, 15:50

Yes broken car. Good transmission.

Dean (who's seen more cars than anybody) reckons the 5 speed to be much stronger than the six.

Dev: Over here, MR'S' is a JDM import....

Dev · July 27, 2019, 17:58

Sorry I didn't get the jist of it. We usually have complaints of the transmission being weak and breaking.
Some wanted an adaptor for a stronger transmission option.

Joesson · July 27, 2019, 19:42

Quote from: Carolyn on July 27, 2019, 15:50Yes broken car. Good transmission.

Dean (who's seen more cars than anybody) reckons the 5 speed to be much stronger than the six.

Dev: Over here, MR'S' is a JDM import....

When I first bought my 2, which was some time before I found the ROC, I first of all asked Mr T about servicing costs. The service manager asked what gear box my then prospective purchase had. It's a five speed says I, that's good says he, it's a "better" box.

tets · July 28, 2019, 06:55

Do you know what markings are on it - reason being I bought an import box with lsd a while back and the bell housing has C60 on it I think and something different on the main box. Unfortunately I'm in France at the minute so can't check

Carolyn · July 28, 2019, 07:56

Quote from: tets on July 28, 2019, 06:55Do you know what markings are on it - reason being I bought an import box with lsd a while back and the bell housing has C60 on it I think and something different on the main box. Unfortunately I'm in France at the minute so can't check

I haven't seen it yet. Dean just told me about it, I'll be there on Tuesday, so I'll have a look. Mind you if Dean says it's a JDM with LSD, then it will be so.

tets · July 28, 2019, 09:16

Thanks Carolyn - I bought mine from a random person but it had come off a white import
I'm back on Sunday so will double check mine but if memory serves I think it was once said that JDM boxes had a C60 housing

Regards
Steve

Carolyn · July 28, 2019, 10:45

I've done my best to read the Transaxle number on my car. This car is a JDM with LSD.

it's 056 /07B

The 056 refers to the Closer ration mid gears and lower different final drive ratio. The 07B means Torsen LSD (the 'B' at the end.)

Hope this helps

Carolyn · July 28, 2019, 10:51

My research indicates C60 are six gear, while C50 are 5.

There's a whole Wikipedia page on it. Gets complicated.

tets · July 28, 2019, 11:10

Ok so I just found an old email I wrote with the info on - mine has C50K stamped on the box and C60 on the bellhousing
Wiki suggests some j spec boxes used the C60 bellhousing so it could be one

I bought it as the imports have a better final drive but I might have got lucky!

Dev · July 28, 2019, 14:11

Most of the transmissions will have c60 markings.

In the US we get a similar or possibly the same 5 speed transmission as that JDM with and without the LSD that came on later years. If that is the case those don't hold up to more power just the same without eventually breaking.

However there has been some speculation that the shaft size between the 6 and five speed might me different in thickness.

Dev · July 29, 2019, 16:34

I went ahead and researched. It would appear the transmission in question is the C56 and it's the most common transmission for the MR-S which is what we have state side and is not particularly JDM.

Its not any better than what you guys are using (except for a shorter gear ratio) which is the C63 which is far more rare .
As a matter of fact many on our side have had issues with the C56 breaking just as much as the C60. Some here actually upgrade to the C63 that gets imported from wrecked Roadsters on your side for the 6th gear and LSD. Some have also used the C63 with their turbo and supercharged builds with no issues.

I suppose its a case of the grass is greener on the other side and Im willing to bet many owners on my side would be willing to trade transmissions.

Carolyn · July 29, 2019, 16:42

Mine is C50

Dev · July 29, 2019, 17:05

Quote from: Carolyn on July 29, 2019, 16:42Mine is C50

Interesting. It would seem that you guys were given an early transmission for the year 2000-2002.

Where as we received the C56 for the manual and a C50 for our version of the SMT. The difference is a closer ratio between 3rd and 4th gears.

I wonder what the rational for doing this was when they could have supplied the same C56 transmission to all markets.

It could be the final drive ratio.

shnazzle · July 29, 2019, 17:09

I'm decently sure no jdm boxes made it to the US. The only reason we have them is from import cars, which we can do as they're right hand drive.
It'd be good to have one of each kind, 5 and 6 speed, rip them all to bits and compare them.
Alas..nobody in their right mind would want to do that

Carolyn · July 29, 2019, 17:13

As Patrick points out, my car is a Japanese import 2001. The engine is a little different to the Euro one too and made in a different factory.

This is the box our 750 club racers all go for. Makes for a livelier car on the twisties.

Edit: Japanese MR S = Midship Runabout Sport.. American: MR2 Spyder ,is a different beast, and then there's the European MR2 Roadster.

The LSD in the early MR S was a non-standard factory option. Hence very rare.

Gaz mr-s · July 29, 2019, 18:15

Although the 'boxes in the US wouldn't be termed 'JDM', do they not use the same gear ratios.?
(Less sure of final drive though)

I had believed that everywhere used the same 1-5 ratios other than the UK market getting longer 3rd & 4th.

Dev · July 29, 2019, 18:20

Quote from: shnazzle on July 29, 2019, 17:09I'm decently sure no jdm boxes made it to the US. The only reason we have them is from import cars, which we can do as they're right hand drive.
It'd be good to have one of each kind, 5 and 6 speed, rip them all to bits and compare them.
Alas..nobody in their right mind would want to do that

From the information I have available the JDM box is a C56 which is the same transmission that was supplied to the US market. The addition of the LSD was an option in the US market in 2004 and 2005. This is particularly for the manual transmission. The SMT received a different variant.

I referenced the wiki article.

https://en.wikipedia.org/wiki/Toyota_C_transmission

Dev · July 29, 2019, 18:34

Quote from: Carolyn on July 29, 2019, 17:13As Patrick points out, my car is a Japanese import 2001. The engine is a little different to the Euro one too and made in a different factory.

This is the box our 750 club racers all go for. Makes for a livelier car on the twisties.

Edit: Japanese MR S = Midship Runabout Sport.. American: MR2 Spyder ,is a different beast, and then there's the European MR2 Roadster.

The LSD in the early MR S was a non-standard factory option. Hence very rare.

There are different variants but on the whole the engines and transmissions are the same between the JP and US markets.
The ECUs and such are different.

We have 1ZZ engines from other cars like the Corolla that are different. They are made in the US and have different valves and rods however we are able to adapt to those engines without any issues or modifications.

Carolyn · July 29, 2019, 18:35

From the transaxle number on m the chassis plate JDM car, my gearbox is a C50. End of.

Dev · July 29, 2019, 18:38

Quote from: Gaz mr-s on July 29, 2019, 18:15Although the 'boxes in the US wouldn't be termed 'JDM', do they not use the same gear ratios.?
(Less sure of final drive though)

I had believed that everywhere used the same 1-5 ratios other than the UK market getting longer 3rd & 4th.

I don't think anything gets termed JDM per say. I think its the transmission designation model. If they match its the same transmission.

One thing that I find that is interesting is that there were two different LSD options for the C56 transmission.
I think the most common one was the torsion and its possible that they had a clutch type.

It makes me wonder why they had a non torsion type and where it was used.

Gaz mr-s · July 29, 2019, 18:55

Quote from: Dev on July 29, 2019, 18:38I don't think anything gets termed JDM per say.

It's a colloquialism for any car stuff that wasn't available here but is regarded as something good that was available in Japan.