Hi-Gear Engineering Ltd

Tel: +44(0)1332 514 503
Email: info@hi-gearengineering.co.uk

MG TD TF 5 Speed Gearbox Conversion

The MG T type 5 speed gearbox conversion kit has been developed as a further successor to the popular MGA and MGB 5 speed gearbox conversions designed and developed by Hi-Gear Engineering Ltd.

The kit is aimed at T type owners who really want to use their cars on modern roads including motorways and who do not want to be confined to secondary roads.

The TD and TF models drive beautifully but when on fast modern roads the engine revolutions become altogether too high for economy, comfort and engine life.

ImageTwo kits are available to cover TD and TF models.

The conversion adapts a Ford Sierra Type 9 gearbox (5 speed, 1.6L & 1.8L: 1982-91, & 2.0L: 1982-87) to the XPAG and XPEG engines.

To enable the Ford gearbox to be fitted to the vehicle, the engine has to be moved Imageapproximately 10mm forward.

The kit has all the parts to enable this to be achieved safely and reliably together with all fasteners and fitting instructions for the competent owner to fit.

The Type 9 Ford gearbox is not part of the kit but is either supplied by the owner or Hi-Gear Engineering Ltd can supply the gearbox.

The vehicle speedometer will need recalibrating. Several companies are able to do this. Instructions on how to measure the vehicle speedometer characteristics for re-calibration are included together with the details of a suitable company to do the work.

The Kit Comprises TD TF:




1. Cast aluminium Bell Housing.
2. Gasket, Bell Housing to gearbox.
3. Spigot bush.
4. Rear rubber gearbox mounting.
5. Modified front rubber engine mounting.
6. New gearbox support crossmember.
7. Two crossmember side supports/lockplates.
8. Engine mounting packing plate.
9. Exhaust support bracket.
10. Engine torque reaction bracket/bolt.
11. Two floor rail support brackets.


12. Gear lever assembly, chrome.
13. Clutch plate (for 7" or 8" pressure plate).
14. Speedometer cable/circlip.
15. Brake pipe (RHD only).
16. Fan spacer (TF only) + bolts.
17. Modified front wing tie bar (TF only).
18. Propshaft.
19. Gearbox cover in moulded ABS.
20. All bolts and fasteners.
21. Detailed fitting instructions.
22. Loctite.

The Bell Housing is cast in LM25 high strength heat treated aluminium alloy and is robustly constructed. The standard MG 7" or 8" clutch cover are re-used. The standard clutch release bearing and cross shaft system are all retained.

The gear lever sits in the same place as usual so the conversion is not easily detectable.

The gearbox supporting chassis tube is retained. The brackets welded to the tube have a small piece removed but will still be able to be re-used if needed.

Gear Ratios


Standard Ford

Modified Ford

Closer Ratio


























The conversion transforms the car into a usable cruiser. Other benefits include improved fuel consumption, less driver and passenger fatigue, less vibration, longer engine life and fewer broken crankshafts! Motorway cruising is enhanced by the fifth gear.

TD axle ratio 5.125:1
4th gear 14.42 mph/1000 rpm
5th gear 17.60 mph/1000 rpm
70 mph 4854 rpm (4th) ->3977 rpm (5th)

TD/TF axle ratio 4.875:1
4th gear 15.16 mph/1000 rpm
5th gear 18.48 mph/1000 rpm
70 mph 4617 rpm (4th) ->3787 rpm (5th)

TF 1500 axle ratio 4.55:1
4th gear 16.22 mph/1000 rpm
5th gear 19.78 mph/1000 rpm
70 mph 4315 rpm (4th) ->3538 rpm (5th)

The propeller shaft provided in the kit is to the original manufacturer's specification:

Torque: 570 Nm, 422lbft (short duration) MAXIMUM
Speed: 7000 Rpm MAXIMUM.

This corresponds to 5740 engine rpm in fifth gear (ratio 0.82:1) and 7000 engine rpm in fourth gear (ratio 1:1). For any higher values of torque or speed, Hi-Gear Engineering Ltd can refer the customer to the manufacturer.

Price: TD 1050, TF 1075 All plus carriage, packing and VAT.

Note. Chronometric Speedometers (Early TD)

This type of instrument is difficult to recalibrate. Hi-Gear Engineering has commissioned Speedograph Richfield to manufacture to order a small step up gearbox which will fit directly into the speedo cable entry point on the Ford type 9 gearbox. This gearbox will then drive the original cable to the speedometer. The owner sends his speedo together with calibration data obtained from the vehicle to Speedograph Richfield who will check the instrument and supply the step up gearbox with correct ratio for accurate speed indication.

For More Information On Our Gear Box Conversions For Classic MG Cars, Call Hi-Gear Engineering Ltd,

Tel/Fax: +44(0)1332 514503


Suppliers of Five Speed Conversion Kits to:

  • Moss Europe
  • Moss Motors
  • MG Owners Club