Thread: Speedo Drive Worm Gears

Originally Posted by Bush65

This has come up a couple of times recently.

Listed below are known part number, colour and number of teeth/starts for some speedo worm gears. These fit the LT230 and by selecting an appropriate gear can help calibrate the speedo when tyre diameter is changed.

90/110 speedo drive gears
frc3310 blue - 20 teeth
frc3311 green - 21
frc3312 yellow - 22
frc3313 red - 24

Discovery 1 [200Tdi/V8]
frc3310 blue - 20 diesel
frc9339 - 23 [see note]

frc3310 blue - 20 V8 efi
frc9339 - 23 V8 twin carb

Note frc9339 diesel for gulf states vehicles,no colour code listed, auto trans Tdi vehicles.

Thanks for the info, I have discovered that the 23 tooth (colour not mentioned above) gear I found in my recently installed second hand LT230 (Prefix 25D) was black. I have since reinstalled my blue 20 tooth one in its place.

Cheers,

Phil

Do these fit LT95's?

Is there any knowledge of which gear suits what?

I can see that they have been listed under 90/100 and D1, but for example the Blue 20 tooth (FRC3310) is evident in both transfer cases, where one runs 29" tyres and the other runs 32" tyres.

Or more to the point in my case.... which does the Defender typically run?

Our findings might be of interest to this thread.

We have a Isuzu 4BD1 with LT95 4 speed from a 1982 Landie, Today I picked up the replacement speedo drive gear for our 1988 Rangie.

Our problem while doing 80km/h the speedo showed 110 km/h, we are running standard tyre sizes.

Original speedo drive gear
red - 20 teeth
22mm overall diameter

Replacement speedo drive gear
no colour - 22 teeth
24mm overall diameter

Glenn

Sorry it has taken a while to give an update, the replacement speedo drive gear has made no real difference to the speedo readings, that means that we have now tried a red 20 tooth gear and a 22 tooth gear with no colour, I have also changed the Speedo itself to a Speedo from a Manual, our vehicle was originally an Auto.

I'm stumped as to where to go from here, any ideas?

A bit of background, the vehicle was originally a V8 Auto, the 4BD1 and LT95 were originally in an early 80's Landie trayback.

Still using standard rubber.

Glenn

Originally Posted by Vern

Do these fit LT95's?

The plastic gear and gear housing are interchangeable between LT230 and LT95's that have the larger 110 handbrake on them. The rangie and stage 1 boxes with the small handbrake have a different diameter shaft on the plastic gear and are not interchangeable with the LT230 ones unless you change the housing as well. If you are changing gears you also have to change the worm drive collar on the rear output shaft as there are different worm ratios to suit different vehicles. Pretty sure the 20/21 blue and green ones run on the same worm drive.

Re hashing an old thread here, but was wondering if all the worm drives are the same on the lt230, and its just a matter of changing the speedo gear drive? I'm about 8% over.

Originally Posted by Vern

Re hashing an old thread here, but was wondering if all the worm drives are the same on the lt230, and its just a matter of changing the speedo gear drive? I'm about 8% over.

Damien not 100% on this one as I don't see the internals of an LT230 very often but I think so.