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Amicale Spitfire
The noisy diff page
   That is now the fourth time I exchange the diff on my Spit. The three times before, I tried to recondition it by myself, following very carefuly the workshop manual, working with the appropriate gauges and instruments, new washers and bearings etc.. I only obtained different types of noise, always at higher sppeds, beginning around 50/60 miles. Depending of the inner adjustments, the diff was more noisy when asking power, or when engine brakes. At the end I thought my crownwheel/pinion couple was too worn to be reconditionned (nothing visible though).

   I never had the kind of noise I found on the fourth diff, a fresh-reconditionned one...

   I have many experiences of mounting various diffs on various spitfires, but that one is the first reconditionned I mount. So is it possible that it needs a running in, a normal noisy period at the beginning to be quiet after a while ? (Yes I put oil in it, and made it go everywhere inside before mounting on the car).

Spitfire Differential soundold_diff.mp3 (337 ko)
MY OLD DIFF : NOISY
   That diff has a "normal" wear, so it becomes *very* noisy at higher speeds, the whining noise starts at 55 miles and it's deafining at 75. On the record I drove at 75, and when I leave the accelerator pedal the noise clearly stops. I precise this diff was not noisy at all at lower speeds. Nothing to hear from the rear when starting to move the car.

MY NEW DIFF : NOISY
   On this new (reconditionned) diff from Canley Classics / John Kipping, I was very surprised to hear (and loud !) the diff just afer starting in first gear. If it was not on the same car, the same day after exchanging the diff, I would have said it was a kind of wheel bearings problem. Fortunately the diff is not noisy at 75 like the worn one...

Spitfire Differential soundkippingdiff.mp3 (618 ko)
   On the recording, I drive very slowly, only first and second gear. We hear a noise from the beginning, even at the speed of a walker. The noise comes from the diff, more or less like worn bearings. I was in the car so I testify the noise come clearly from the diff.
   At the end, (just after I say "twenty"), I put the gearbox on neutral and it is the most interesting part, we ear a very noisy diff while coasting untill the car completely stops. (Two different ends in the sound file, the car stopping in neutral, no brakes).

   Please use good loudspeakers if you can to check the sounds. Not the standard plastic computer type, if possible. Best is to use headphones, even the light walkman type.
may 2001 - Amicale Spitfire