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Q: Engine RPM Oscillates When I Come to a Stop and Thumps When Placed Into Drive

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Whenever I place the car into Drive, the car makes a loud thump like a glove hitting a boxing bag. When I come to a stop while in Drive, the engine RPM oscillates as if it's stuck in gear (see link). When I place the car into Neutral, there isn't any oscillation. Now I've just had the transfer case and front differential replaced from a 52,000 mile Grand Cherokee. Occasionally, ill get the "Service 4WD" notice. As a side note, there seems to be a whirring in the front right tire. (https://youtu.be/To_C5S0ZPgg)

My car has 88500 miles.
My car has an automatic transmission.

A: Hello. The throttle issue is likely related...

Hello. The throttle issue is likely related to the throttle body or mass air flow sensor needing to be cleaned and tuned. It could be transmission related, but that’s not likely.

The clunking could be related to a bad or failing mount for the engine or transfer case. From the video, it is really hard to tell. If it is a very consistent issue I would blame a mount. A qualified technician should inspect the engine and transmission mounts, as well as suspension, for any play. A certified mobile mechanic from YourMechanic can provide this inspection at your home or office.

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