Vehicle 2004 1st gen Xterra, automatic transmission.

My transmission is making an audible 'thud' or 'clunk' and making the whole car shake when switching from P to R, from R to D and back, etc (basically shifting gears while stationary). Only does this when the car is cold (after sitting overnight). After the car is driven even a bit and the engine is up to operating temp, seems to shift just fine. Only noticed this the last few days - one thing to note is that it's been cold outside (-10c). Having said that, I I don't remember it doing this last winter.

Does anyone else experience this in the winter? Wondering if this is normal for automatic transmissions?? I'd imagine that with cold weather, the tranny fluid is more viscous - which explains why shifting gets better once the car is warm/driving.

I did flush the tranny fluid last year with synthetic. Vehicle only has 180,000km...

A few things I can think of: - Somehow some moisture got into the tranny oil and it's freezing and causing harsh shifting? - When the tranny is cold all the metal parts shrink so I'd imagine you'd get worse tolerances so might have some internal leaks in the fluid? Wondering if this is a sign that my tranny is on the way out?

Any ideas?

  • 2
    First thing to check is universal joints. These are easy to diagnose by a mechanic and not a wallet buster.
    – Jupiter
    Jan 14, 2020 at 23:44
  • Is the engine revving higher than it should be when it is cold?
    – HandyHowie
    Jan 15, 2020 at 9:04
  • I would imagine the u-joints wouldn't be effected by temperature, so the clunk would be there even after the engine warmed up, no?
    – wild.coast
    Jan 15, 2020 at 11:32
  • @HandyHowie no, revs are to spec and haven't changed. Why do you ask?
    – wild.coast
    Jan 15, 2020 at 11:33
  • 1
    If the revs are high when a gear is selected you can get a thud and if the engine mounts are weak it could cause the engine to move considerably.
    – HandyHowie
    Jan 15, 2020 at 11:45


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