W58 Version Comparisons

[medwin46]

Hey all

I know there is a thread on here somewhere but 20 minutes of searching returned no trace of it so here is another repeated question regarding the w58 supra gearbox.

To my knowledge there are 4 different versions of W58. ( i am only talking 58, not any other w series box) most easily distinguishable by the shifter position. The box i have has a far forward shifter position and is from an 85 celica supra that had a 22R ( i think?!?) enigne. I know it is a 58 as it is stamped on the firewall! (though even this could be a lie from toyota, who know's! !!!)

Apparently the latest version of W58 came with a steel sandwich plate, and the furthest rear ward shifter position. Apparently these are the strongest of all W58 boxes, due to having bigger bearings and evident because they were used up to 95?? in non turbo supra's... correct??

So basically im asking if anyone on here knows FOR CERTAIN that the steel sandwich plate version is stronger or not, or for any certain infomation regarding this mystery and rumours behind the W58 box!

Thanks guys

[Norbie]

Yes the steel sandwich plate versions are obviously stronger since the gearset is supported by a steel plate instead of an alloy plate. An alloy plate is more likely to flex under heavy torque loads; flex = misaligned gearset = shredded gears.

Wilbo and I compared a late W58 with an early W58 and we found a few minor differences - some of the bearings and gears are slightly wider and the synchros are a different design - but the main difference in terms of strength is the steel plate.

[medwin46]

Yes the steel sandwich plate versions are obviously stronger since the gearset is supported by a steel plate instead of an alloy plate. An alloy plate is more likely to flex under heavy torque loads; flex = misaligned gearset = shredded gears.

Wilbo and I compared a late W58 with an early W58 and we found a few minor differences - some of the bearings and gears are slightly wider and the synchros are a different design - but the main difference in terms of strength is the steel plate.

So i'd definately be better off with a steel plate box than an alloy?

Cheers for that!

[Hen]

I feel the thought that the alloy plate W58 is weak is rubbish. Even if it is an alloy plate, it's about an inch thick. What sort of force would you need to move a 50mm OD bearing even 1micron when mounted in an inch thick plate of alloy?

Hen

[medwin46]

I feel the thought that the alloy plate W58 is weak is rubbish. Even if it is an alloy plate, it's about an inch thick. What sort of force would you need to move a 50mm OD bearing even 1micron when mounted in an inch thick plate of alloy?

Hen

Closer to an inch and a quarter actually...

But in theory it kinda makes sense it'd be stronger. If the alloy plated one was going to be enough to withstand the supra, they would not have spent the money revising what was already a strong box. The fact that the steel sandwich plate version was made to go in supras pushing 260hp or whatever says they must be a little stronger than the alloy plate.

[The Real Roadrunner]

Closer to an inch and a quarter actually...

But in theory it kinda makes sense it'd be stronger. If the alloy plated one was going to be enough to withstand the supra, they would not have spent the money revising what was already a strong box. The fact that the steel sandwich plate version was made to go in supras pushing 260hp or whatever says they must be a little stronger than the alloy plate.

um, i dont think you will find a w58 behind any factory 260hp motor as they didnt use them for turbo engines apart from 1ggte's which were only around 200hp.

im not sure about the steel plate boxes and what exactly theyre out of as ive seen alloy plate jza80 boxes also.
there must have been a changeover date between the two but i cant confirm when.

cheers
linden

[30psi 4agte]

I feel the thought that the alloy plate W58 is weak is rubbish. Even if it is an alloy plate, it's about an inch thick. What sort of force would you need to move a 50mm OD bearing even 1micron when mounted in an inch thick plate of alloy?

Hen

I agree here ! even though .......In theory the steel plate is stronger the amount of difference between the alloy plate box and steel plate would be un-measurable and you would want to be making some SERIOUS power to even worry about the sandwhich plate.

FWIW im using a W57 (alloy plate) box and have had no probs with it behind my engine.
If i break........... Correction there : WHEN i break the box i can tell you it wont be because of an alloy sandwhich plate

[Norbie]

I've broken two alloy-plate W57's and two steel-plate W58's, and it wasn't SERIOUS power that did it (about 300-320rwhp). The alloy ones had a much shorter lifespan than the steel ones. I can't say how much of this was due to the plate and how much was due to other design changes but there's no doubt in my mind the steel boxes are stronger.

[wilbo666]

im not sure about the steel plate boxes and what exactly theyre out of as ive seen alloy plate jza80 boxes also.
there must have been a changeover date between the two but i cant confirm when.

cheers
linden

The change over was 89 according to the EPC, So some MA70's have alloy plate ones and some steel plate.

I had a pdf hosted with some detailed differences, I don't think it is hosted anymore. I can drag it up is someone wants to host it...

Cheers
Wilbo

[LeeRoy]

I've broken two alloy-plate W57's and two steel-plate W58's, and it wasn't SERIOUS power that did it (about 300-320rwhp). The alloy ones had a much shorter lifespan than the steel ones. I can't say how much of this was due to the plate and how much was due to other design changes but there's no doubt in my mind the steel boxes are stronger.

At the same time though most people (and im assuming you can be included here also norbie) are using gearboxes that are not only second hand but also have the possibility of having been given hard lives. At the same time you could have had alloy boxes that had been given a real flogging and that may have attributed to their shorter lifespan.

For a true indication you would really need to have used both gearboxes from new and even then ones driving style is full of so much fluctuation and variables that it would not be a good way of testing them for comparative strength.

[The Real Roadrunner]

the jzx90 box i got for moss was also alloy plate, so there must be some weird shite going on with toyota.

[Norbie]

At the same time though most people (and im assuming you can be included here also norbie) are using gearboxes that are not only second hand but also have the possibility of having been given hard lives. At the same time you could have had alloy boxes that had been given a real flogging and that may have attributed to their shorter lifespan.

True, although I was exceedingly gentle with my alloy-plate boxes because I knew they were going to break at any minute!

[Draven]

exceedingly gentle

For you, maybe

[cambelt]

No jza 80 N/A had a alloy plate W58 , ive seen over 30 of them all to be steel
On another note has anyone got a W55 OR a W 57 thats allready apart they could count the 5TH gears teeth , both the main an the counter gear
Dave

[30psi 4agte]

Anyone have any ideas as to what it is that actually breaks in these boxes ???

I have herd that second gear can strip its teeth pretty easy...... Is this the usual cause