T-9 Speedo Driven Gear

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DPDISXR4Ti
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T-9 Speedo Driven Gear

Post by DPDISXR4Ti »

One of the things we noticed driving Darren's T-9 swapped Scorpio home yesterday is that the speedo reads fast by at least 10% - probably more like 15%. I'm wondering why/how this could be true - didn't all Merkur Scorpios come with the same 3.64 rear-end?

Doing some quick searching I find this forum thread on the UK Scorpio forum...
http://www.fordscorpio.co.uk/cgi-bin/ya ... 1267895854

Specifically this...
Note : The Scorpio speedo reads higher than actual speed (approximately 10%)
If you fit the VSS from the next lower ratio diff the speedo will read almost exact speed.


So I guess I first need to figure out what speedo driven gear is in there, and then I need to figure out how to get one with one less tooth. I seem to recall reading that Contour VSS's could be used, so I assume from that the speedo gears are the same format and could thus be a donor if the tooth count is what I need.
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Re: T-9 Speedo Driven Gear

Post by brokencase »

You can get different vss gears from any of the several transmission part suppliers on the web.

I can't remember how many teeth are on the original auto trans scorpio has - might be 20. But it is relatively easy to pull and check.
I doubt the T9 is the same number of teeth. Whatever it is you will want to get one with ~10% more teeth.

Bigger issue is unreliable Scorpio Hall Effect Vss sensor. They don't last. The new replacement ones they sell in Europe are crazy price.

See my discussion of adapting the more reliable inductive Ford Ranger type Vss here...
http://forum.merkurclub.com/forum/viewt ... 29&t=32548

FWIW, I have compared my auto Scorpio's speedo with GPS and it is about 4% off. As I recall it reads less than actual.
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Re: T-9 Speedo Driven Gear

Post by DPDISXR4Ti »

But is the T-9 driven gear easily replaceable like it is on the T-5 and A4LD?
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Re: T-9 Speedo Driven Gear

Post by dimswits »

Unfortunately Brad, the Scorpio T9 speedo sensor is an oddball compared to what we commonly see. It is not the same as the A4LD sensor and cannot use the standard ford speedo gears. The body is a lot larger diameter, and it's mounted to the driver side of the tailhousing rather than the passenger side. If you have an XR T9 handy, the sensor goes in the bore where the XR T9 has a large steel plug.

The driven gear looks more like these: http://www.thegearbox.org/i//driven_gears.jpg, but I don't recall it having the long snout bearing surface like those.

If you wanted to use the contour sensor, you'd have to swap the tailhousing to an XR housing (non-trivial unfortunately), and find a replacement driven gear for that (those DO look pretty identical to the linked gears). You can then get an adapter from Burton that fits to the T9 with a snap ring and accepts the threaded contour sensor, which is electrically identical to the Scorpio sensor.

D
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Re: T-9 Speedo Driven Gear

Post by DPDISXR4Ti »

dimswits wrote: Fri Apr 27, 2018 8:58 am The driven gear looks more like these: http://www.thegearbox.org/i//driven_gears.jpg, but I don't recall it having the long snout bearing surface like those.
So why can't I just get one of these with the correct tooth count and swap it in? The tail doesn't need to come off, right? It's just like a T-5 in that regard, just a different size gear, yes?

On the Contour VSS, I recall years back someone made an adapter(?) to use that in conjunction with the original VSS. Does the donor Contour VSS need to be a manual transmission? This would just be something I would grab in case the original VSS fails.
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Re: T-9 Speedo Driven Gear

Post by dimswits »

DPDISXR4Ti wrote: Fri Apr 27, 2018 12:15 pm So why can't I just get one of these with the correct tooth count and swap it in? The tail doesn't need to come off, right? It's just like a T-5 in that regard, just a different size gear, yes?

On the Contour VSS, I recall years back someone made an adapter(?) to use that in conjunction with the original VSS. Does the donor Contour VSS need to be a manual transmission? This would just be something I would grab in case the original VSS fails.
I don't believe those gears are exactly right, they just look similar to the one on the end of a Scorpio T9 VSS. You could pull yours and have a look. The gear is removable from what I remember. Unfortunately I long ago misplaced my T9 VSS.

The Contour VSS is auto or manual Contour. Early auto contours have a speedo cable passthrough, later ones don't. The adapter that was made adapts a standard ford VSS bore to the contour threaded sensor. It would work on an A4LD, C3, or T5, but not on any flavor of T9 that was available stateside.

I do have some of this stuff handy, I'll see about getting some pictures.
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Re: T-9 Speedo Driven Gear

Post by brokencase »

They appear to be available on ebay (in different numbers of teeth) but they come from across the pond...and are pricey..

https://www.ebay.ie/sch/Car-Parts/6030/ ... ive+type+9
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Re: T-9 Speedo Driven Gear

Post by DPDISXR4Ti »

brokencase wrote: Sun Apr 29, 2018 8:54 pm They appear to be available on ebay (in different numbers of teeth) but they come from across the pond...and are pricey..

https://www.ebay.ie/sch/Car-Parts/6030/ ... ive+type+9
Thanks. I wonder if they're the same format as anything over here. What about the Contour speedo gear? Can't find a definitive image of it, but seems to be more like a typical T-5/A4LD gear.
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Re: T-9 Speedo Driven Gear

Post by dimswits »

DPDISXR4Ti wrote: Mon Apr 30, 2018 4:10 pm
brokencase wrote: Sun Apr 29, 2018 8:54 pm They appear to be available on ebay (in different numbers of teeth) but they come from across the pond...and are pricey..

https://www.ebay.ie/sch/Car-Parts/6030/ ... ive+type+9
Thanks. I wonder if they're the same format as anything over here. What about the Contour speedo gear? Can't find a definitive image of it, but seems to be more like a typical T-5/A4LD gear.
These will not work in the USA Scorpio T9. They are for the T9s with a cable speedo.

Lower left sensor in this image is what is installed in a Scorpio T9, and the item underneath it is a blanking plug that is installed in an XR T9:

Image

This item is the newer, plastic bodied version with the updated triangular connector, note the shape of the shaft on which the gear is installed:
https://www.ebay.co.uk/itm/GEARBOX-SPEE ... 3427510929
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Re: T-9 Speedo Driven Gear

Post by brokencase »

Dimitri - Given the lack of availability would it be worth trying to take the "Speedo Cable" type gears and machine them to fit the Scorpio Hall effect sensor?
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Re: T-9 Speedo Driven Gear

Post by Ed Lijewski »

Maybe look at Inatrument panel speedo gear options if variations are available.

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Re: T-9 Speedo Driven Gear

Post by dimswits »

brokencase wrote: Mon May 07, 2018 1:12 pm Dimitri - Given the lack of availability would it be worth trying to take the "Speedo Cable" type gears and machine them to fit the Scorpio Hall effect sensor?
Seriously doubt it. Here's what it looks like: https://www.motomobil.com/schaltgetrieb ... 760-2.html
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Re: T-9 Speedo Driven Gear

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Re: T-9 Speedo Driven Gear

Post by brokencase »

If it were me I would probably take measurements off the old one, model it in CAD, adjust tooth count, and then 3d print a new one in Nylon.

But that's just me...
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