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Dr. Hamman
Dr. Hamman, Automotive Engineer
Category: Car
Satisfied Customers: 6286
Experience:  30 years experience, Repairing, building, & designing, automobiles.
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crown: highway speed..there is a slight hum or whine..coasting

Customer Question

Hello, I have recently installed an MGA crown and pinion into my MGTD fifferential.The change made a reasonable difference in the gear ratio and I was able to get a little more highway speed with less revs.However, there is a slight hum or whine when not under power or coasting in neutral.I think I failed to get the pinion length properly measured.Can this damage the new crown and pipion?
Thanks Dick Hales.
Submitted: 6 years ago.
Category: Car
Expert:  Dr. Hamman replied 6 years ago.
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Dr. Hamman :

Dick, the pinion length/depth is critical for the gears to operate properly. If the pinion depth is out of spec enough the gears will experience accelerated wear, and be noisy. I have seen many problems in this area. This is something you need to check out soon, or the gears might be damaged. Most of the time gear manufacturers only allow as little .002 inches, or .050mm during installation. If you are out .1mm or more you can get accelerated wear, and noise.

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