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MG TD TF 1500 - TC and TF Gearbox Speedo Drive Ratios

Fellas

Inquiring whether there are different gear box output speedo drive ratios for these two model gearboxes.

As I have indicated previously I inherited my TF with a PO fitted TC gearbox. Finally put the TF on the road today and the speedo is reading high.

Can anyone assist with a solution other than fitment of a reduction box in the speedo cable.

Thanks

Graeme
G Evans

Graeme, I think it more likely that the gears in your speedometer were changed to match the TPM (turns per mile) of the TC gearbox. I would guess that you 'only' need to install a set of the OEM speedometer gears. Bud
Bud Krueger

It may be worth talking with an instrument repair company. They may be able to recalibrate the speedo to suit.

You may also look to see if the rear flange from the TF can be put on to the TC gearbox. You could then also put the TF speedo drive pinion in. I have both of these gearboxes out of the cars so I could investigate this for you if you wish,
Max Irvine

Max

Many thanks for the offer, would really appreciate if you can investigate this solution.

Thanks

Graeme
G Evans

Graeme, I had a look at both gearboxes and it will not work. The TF flange does not have the speedo drive scroll whereas the TC does. The TF scroll is at the back of the actual gearbox and not at the rear of the extension.
Max Irvine

Max

Many thanks, looks like the solution is to insert a reduction gearbox in the speedo drive cable.

The situation grew more legs today when I went to remove the pinion housing. As is typical on the TC gearbox the rear flange had been broken and welded up, the welder has managed to prevent removal of one of the housing screws.

I will surmise the speedo pinion gear has 9 teeth as I hesitate to think how I can remove the housing to prove this is the case.

Graeme
G Evans

Graeme I think you are correct about 9 teeth for a TC box, TF is 15 (I think)
Max Irvine

Graeme,
There is a TC rear flange and speedo drive on Australian ebay at the moment. It has a 15 tooth drive which would give a different ratio to the standard 9 tooth drive. I know the seller and asked him if the parts mesh, he said they did. It may be worth checking out but I think it is a bit expensive. Also I would still need to be convinced that they will mesh and be the correct ratio for you.
Max Irvine

Max

Thanks mate, think I will take the speedometer recalibration option as I know I can obtain the desired outcome.

Graeme
G Evans

This thread was discussed between 03/10/2013 and 12/10/2013

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