Gearbox/diff codes

[Petrus]

Does anyone know what the various codes for gearbox/dif on the id tag are.

Per example 01AC56 meaning?

or 02BC52M?

or...?

Is there a listing somewhere.

Thanks.

[shnazzle]

Does anyone know what the various codes for gearbox/dif on the id tag are.

Per example 01AC56 meaning?

or 02BC52M?

or...?

Is there a listing somewhere.

Thanks.

C52,C52M,C56M,C65M,C66,C66M are the gearbox type. 

01A, 02B, 02A are the diff options.

01AC56 is a 5-speed gearbox without LSD. Think the C56 is the MR-S gearbox.

[Gaz mr-s]

From Wiki.    Patrick was correct.

C56

A 5-Speed Manual Transmission for FWD and mid-engine cars. Compared to the C50/52, it features close-ratio 3rd-to-4th gearing.

Gear ratios for this transmission.
1st    2nd    3rd    4th    5th    Reverse    Final
3.166    1.904    1.392    1.031    0.815    3.250    4.312

Differential Options:

    C56-01A: Open Differential
    C56-01B: Torsen Limited Slip Differential (LSD)
    C56-03A: Open Differential
    C56-04C: Limited Slip Differential (LSD)

[Petrus]

Thanks guys!

There are various more box/diff combos.

There are also C52 5 speed and C65 plus C66 6 speed boxes.
Thus as far as I can tell 4 different boxes.

Even the lsd can be torsen of helical. Thus at least two diff types.

The M at the end seems to be SMT.

The 01A  c.q. 02B seems to indicate open/lsd as well as type of lsd and final reduction bolted to the diff. I mean, the end reduction must be somehow coded too no?!

Mý car has the older C52 5 speed, the M for SMT and 02B for a Torsen (?) LSD.

[shnazzle]

Thanks guys!

There are various more box/diff combos.

There are also C52 5 speed and C65 plus C66 6 speed boxes.
Thus as far as I can tell 4 different boxes.

Even the lsd can be torsen of helical. Thus at least two diff types.

The M at the end seems to be SMT.

The 01A  c.q. 02B seems to indicate open/lsd as well as type of lsd and final reduction bolted to the diff. I mean, the end reduction must be somehow coded too no?!

Mý car has the older C52 5 speed, the M for SMT and 02B for a Torsen (?) LSD.

Whatever you do, don't open the box of which car came with which gearbox I will lock the thread in advance of the arguments I know will come Right @Carolyn?

[Petrus]

Whatever you do, don't open the box of which car came with which gearbox I will lock the thread in advance of the arguments I know will come Right @Carolyn?

No need.
Have cristal clear that the C-family boxes is highly ´flexible´ as in parts commonality and mixmatching and that Toyota did so. That even some case markings are no guarantee of which cluster is inside because of the commonality.
See the C52 with lsd mounted in mine.

I know what´s in mine. It was never swapped and thus the id plate rules ánd it behaves as it should.

I ám however curious about the typlogy of the diffs and reductions; where the 2 in 2B or 4 in 4B point at per example.

[Petrus]

Just found a curious bit of info confirming the case markings/ clusters:

A version stamped C50-M1 used in the 2000–02 MR2 SMT Spyder model has the ratios as listed for C52. - infogalactic/wiki.

[shnazzle]

Just found a curious bit of info confirming the case markings/ clusters:

A version stamped C50-M1 used in the 2000–02 MR2 SMT Spyder model has the ratios as listed for C52. - infogalactic/wiki.

I done told you... Don't open that box

[Petrus]

Just found a curious bit of info confirming the case markings/ clusters:

A version stamped C50-M1 used in the 2000–02 MR2 SMT Spyder model has the ratios as listed for C52. - infogalactic/wiki.

I done told you... Don't open that box

Just doing my bit to shine a light on the flag not persé indicating the load ;-)

[shnazzle]

Just found a curious bit of info confirming the case markings/ clusters:

A version stamped C50-M1 used in the 2000–02 MR2 SMT Spyder model has the ratios as listed for C52. - infogalactic/wiki.

I done told you... Don't open that box

Just doing my bit to shine a light on the flag not persé indicating the load ;-)

I need to add this to the forum rules. 

"one shall never discuss gearbox versions in relation to MR2  years, guises, markets or types"

[Ardent]

 

[Petrus]

"one shall never discuss gearbox versions in relation to MR2  years, guises, markets or types"

Ah well, that is not my thing so not applies.

A table with the codes and their meaning will do for me. In particular the diff codes.

P.e. 01A vs 03A for open diffs and 1B, 2B, 4C for LSDs.

Just bugs me. Should be simple enough.

[Petrus]

The plot thickens. Best sit down...

Ok, so my car has a C50-M1 stamped gearbox case with the C52 gear cluster. It gets weirder: It has the same helical diff and gearing as the C66M.
Hence the ´2B´ diff code as it is a ´helical´ not the 1B torsen.
This EU spec 2003- C66 is the same as the C52 cluster with a 6th gear added. Still logical.

The UK spec eguivalent has a C65 box which is the C56 cluster with the same 6th gear added but with a shorter diff which if lsd is torsen type.
The C52 and C52 cluster are different in 3rd and 4th being closer together. The others are the same.

My gearing is thus the same as the Europe spec 5th gear and roughly between 5th and 6th of UK spec.

The reason for the EU spec 6th gear being an overdive on the 5 gear box is autobahn spec...

That is a somewhat pleasant surprise ??   as it means my car has a helical lsd which for some reason is supposed to be preferred.
I have no clear understanding of the diffence is between torsen and helical; I though torsen is helical, so that is next.

[Petrus]

Btw. appearantly there is ´history´ concerning gearboxes but regardless, for those with any spirited driving aspirations it is rather important to know which gearbox/totalreduction the car has.
It is all about Archimedes´Law of the Lever.

F = m x a or a = F / m.
Meaning that accelleration is Force devided by weight.
Force being the hp at the wheel.
That is the engine hp at that rpm multiplied by the gear reduction.

Every gear change means you go from one reduction to less reduction at a lower rev.
To know where you land on the torque % power curves in the next gear you need info about the gear box.

Plot the output graphs on top of the gearing graph and you can séé when best to shift for economy to max acceleration.

Neat Covid19 activity too 


Footnotes:
- there is a véry limited number of gear clusters; basically 2, each also with a sixth gear added; the crux is in the diff. and if you cannot establish yours you can easily determain the overall reduction in highest gear by deviding accurate speed through engine revs through wheel circumference

[Petrus]

As far as I have tracked it down now, the ´2b´ in my box is the https://www.trdparts.jp/english/parts/parts_lsd_helical.html







which MRW also lists
https://www.monkeywrenchracing.com/product/trdtoyota-helical-lsd-lotustoyota-c5x-c6x/