Power comes in (from the battery but via the ignition circuit, or wherever you take the power from. Think of the electrical circuit as a straight line. That's a very simple screw-in switch and worth replacing as they do wear. You need to control the overdrive so that it only comes on when in 3rd or 4th, so this switch is an inhibitor and activated by the gearbox levers when the 3rd or 4th gear is selected, and not in any other gear, especially reverse. If this option is of interest please let us know at the time of ordering.Though I am now left wondering what the electrical spade connections circled in my second picture, located on the top of the box are for, I take it they are nothing to do with the overdrive unit? TR2 4 owners can make a new exit hole in the tunnel and along with a suitable speedometer cable ( 504609, 96' long) can run the speedometer cable inside the car so the cable is away from the heat of the exhaust and easy to change by the roadside.

This is ideal for rally car use as the speedometer drive on these units exits the overdrive slightly higher than standard. NOTE 1: To special order we can incorporate a Saloon 'A' type rear case converted to be suitable for fitment to a TR2 6 ( RTR1105EX). Units are not guaranteed for any motor sport including but not exclusively, track days, timed events, race or rally activity. Please see Information Sheet IS0054 for further in formation. We expressly exclude the cost of removal and refit or transport to Revington TR even if the unit(s) is subsequently found to be faulty. We expressly exclude any consequential loss of any kind. We warrant workmanship and parts but do not under any circumstances warrant gear teeth breakage. This 12 month period, in the case of gearboxes/overdrives is finite and will not be extended. We have a limited warranty policy covering overdrives with specific returns policy. Revington TR warrant the overdrive for 12 months from date of purchase only (not date of fitment or date of first running).

A quote to include a 28% ratio can be given at the time of ordering. The disadvantage being that in TR gearboxes with standard ratios, 3rd gear is now very close to 4th gear. For those using low ratio back axles and wishing to improve cruise speed, we can provide overdrives with a 28% ratio. Later TR6 (CF/CR) with 'J' type overdrive provide a 25% increase in ratio with the same but obviously slightly different effect. This conveniently fits between 2nd, 3rd and 4th to give seven genuine gear ratios. see GEARBOX MOUNTINGS: CONVERSION KITSĪll TR2-6 'A' type overdrives provide a 22% increase in ratio. When we supply a 'J' type overdrive on the back of a gearbox for fitment to a TR2 to TR6 CC/CP chassis, an adaptor plate kit will be needed.

We can offer these units outright too on payment of the appropriate none refundable deposit. Revington TR offer a reconditioning service for overdrive units both 'A' type and 'J' type.

Laycock j type overdrive solenoid