Triumph Repair: Spitfire 1500 Gear Oil to use, lucas oil stabilizer, fiat 124 spider

Question
Howard,

  Do you recommend using a lighter oil in the Spitfire tranny to help ease shifting ?  I have synthetic 75W90 in mine and occasionally I get a gear clash when shifting.  Previously I had added 50 % Lucas oil stabilizer and had an awful time changing from 1st to 2nd.  My friend's MGB takes engine oil in the tranny, would you recommend anything lighter than 'gear oil' for a Spitfire ?

  Thanks,

  Steve.

Answer
Hi Steve,
Yes, many British cars and even domestic cars switched to a lighter grade oil to help the syncros work better. However, keep in mind that correct downshift procedure should always be used even when the syncros work well to make them last longer.

The practice of giving the throttle a quick blip just as you down shift and using a moderate speed on up shifting will dramatically extend the life of a gearbox.

Speed shifting on the up shift and not using the throttle on downshift will definitely shorten the life of a gearbox on even the best syncro box in any car. Perhaps the best syncros in any box I seen was the Italian Fiat 124 spider. I had a friend who took great joy demonstrating how good they were by pushing the shift lever into 1st gear at 50 MPH. Until he did it one too many times and the RPM of the input shaft went so high the every shred of the clutch lining disintegrated and went out into the pressure plate.

Howard