W5X Speedo Drive Comparision (Steel plate vs Alloy plate)

[wilbo666]

W5X (W55, W57, W58) gearboxes have two different diameter speedo drive gears that insert into the side of the gearbox!

I recently changed from a Steel plate W55 to an Alloy plate W58 and my speedo no longer worked, I had retained the W55 speedo gear section that is inserted into the side of the box (as it was 99% accurate). I checked that both boxes had 10 tooth internal gears (by checking that both Nylon gears were marked '10'), however the external tooth count was quite differant between the gears (31 vs. 35).

I observed the following
-W58 Alloy plate (10-35 Marked Nylon Gear) OD:~31.5mm
-W55 Steel plate (10-31 Marked Nylon Gear) OD:~28.75mm



This information may help out others that have done a similar sort of thing and no longer have working speedo's *cough Norbie!* (I suspect putting an Alloy plate gear into a steel box may cause the gear to be damaged!).

Cheers
Wilbo

[oldcorollas]

K boxes have similar discrepancies, but the early ones had 5 drive teeth (and 19 driven), and later 6 (20 or 21 driven)
fwiw...


nice find

[CrUZida]

I presume the drive gears have different OD's too?

I guess you didn't notice this?

[Hydra]

Nice work... Will keep this info handy!

[Norbie]

Damn, this is obviously why my speedo stopped working when I installed my steel W58. Well spotted, I would never have seen it!

[JustCallMeOrlando]

Alright, now how do I explain interchanging the speedo gear from my alloy-plate W57 into my steel-plate W58, and having a perfectly working speedo?

[The Witzl]

perhaps this smaller diameter (less teeth) nylon gear is from the W55 gearbox exclusively?

Perhaps RT142 coronas run a different diff ratio to all the W57/W58 fitted cars?


In any case... damn good find Wilbo. + rep your way.

[wilbo666]

I presume the drive gears have different OD's too?

I guess you didn't notice this?

I also can only assume that the driven worm gears have differant OD's as well
(Of course I didn't notice in the middle of the night when I was trying to steady a freaking oily gearbox to put the rear extension housing back on it wasn't something that I thought would be worth a look ). Oh and on that note the steel plate extension housing wouldn't fit onto my alloy plate box (I wanted to use the steel plate extension housing as it had a new rear seal and it also has bearings for the shifter to slide along as opposed to bushes, I didn't have time to investigate it tho!

Also of note is that the steel plate W55 was rebuilt by dellow at some stage, and I have no idea what it was originally out of, the fact that norbie is suffering a similar problem tho does make alarm bells ring

JCMF, dammit it if I can explain that...(maybe the gear went munch munch and the worm gear simply rethreaded the soft nylon? lol).'

Cheers
Wilbo

[JustCallMeOrlando]

Nope, both the gears came out looking 100%, I've swapped them around a couple of times when I was troubleshooting it being incorrect.

[wilbo666]

Perhpas there is 'early' and 'late' Steel Plate W5X gearboxes... I compared my Steel plate box to Norbies trashed Steel plate W58 and they were very similar, however there were differances seen between the Steel and Alloy plate version.

perhaps 'late' model Steel Plate boxes have the smaller OD external gear? (if that was to be the case then maybe you have an early steel plate box?).

Just a possibilty! I really don't know! (I haven't had the chance to compare my steel plate box to a known early MA70 one (as opposed to JZA80 one)).

Cheers
Wilbo

[The Witzl]

... you try to confuse!!!

someone answer these questions!

[Norbie]

I have a vague recollection that there are two or three different drive gears used in W5x boxes (with a different tooth count and I assume OD), and these are only compatible with a subset of driven gears. Perhaps when people like me mix and match gearbox components you can wind up with incompatible gears and things go wrong?

I have a steel W58 and 2 alloy W57 gearsets at home, I'll get busy measuring the drive gears and see if I can spot any differences. Does anyone else have W5x boxes they can measure too?

[wilbo666]

I have a vague recollection that there are two or three different drive gears used in W5x boxes (with a different tooth count and I assume OD), and these are only compatible with a subset of driven gears. Perhaps when people like me mix and match gearbox components you can wind up with incompatible gears and things go wrong?

I have a steel W58 and 2 alloy W57 gearsets at home, I'll get busy measuring the drive gears and see if I can spot any differences. Does anyone else have W5x boxes they can measure too?

I know that there are internal 10 and 11 tooth gears avaliable, however both my nylon gears were stamped 10 and both work in the gearboxes that they originally came from!

Strangness

Cheers
Wilbo

[CrUZida]

There is 9 too.
Nathan has one (verified via maths only, not sight)

Go figure.

[thechuckster]

On the wierd-shit-o-meter this comes in at say a 7 ?