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Discussion Starter · #1 ·
Hi, I have an issue with my automatic transmission. The revs go up and down when I am going on a constant speed. Can anyone let me know what could be the issue please? Have changed the torque converter but the problem is still there.
Additional Info:
1- Car idles fine. No bouncy revs
2- Only happens under steady load (No acceleration or deceleration. Foot steady at the accelerator pedal) . When I accelerate, revs don't bounce and the TC does not slip
3- Does NOT happen when cold. Only when the engine is slightly warmed and so on
4 - Current faults are 1) 41BB-exhaust backpressure sensor and 2) 4A74-LIN/BSD Preheating control unit:Missing

Here is what it looks like:
 

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From the video it appears to be an issue with the TC, that's exactly what mine did before it was replaced, albeit the fluctuations were less frequent. As others have said, who replaced the TC? Where they a gearbox specialist? It's also a good idea to consider reconditioning the gearbox whilst it's out of the car as to simply replace the TC may result in other issues later on such as Ratio Monitoring on any of the 5 clutch packs.
 
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