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Q: Front diff ratios

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I have a 2005 3.0 sport diesel, the front diff needs replacing, the ratio is 3.91. I've been told a 3.73 would fit is this true? If so would I need to change anything else or is it a straight fit
My car has an automatic transmission.

A: Hello. If you are going to change the ratio...

Hello. If you are going to change the ratio, it needs to be done in the rear also. You cannot have different gear ratios in the front and the rear as that would cause the transfer case to fail. These must always match to function properly.

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