Grange running problem

[Longbow]

My new Dapol Grange runs smoothly and quietly on my rolling road but is jerky and very noisy on my clean 11'' radius test track circle. My two other Dapol tender drive locos are exemplary runners. Any diagnosis please?

[Joel Dapol]

Sounds very strange , to be fine on one platform and noisy on another. Is it noisy on all laid track or just your test circle?

[Longbow]

My test track is all the laid track I have. But my tender drive 9F and Hall (and the rest of my fleet) run fine on it. The noise appears to be coming from the tender. If you can suggest any simple fault-finding steps that won't void the warranty I'm happy to try a remedy rather than a return.

[Joel Dapol]

At a bit of a loss on this one. Unfortunately, I would suggest a return and replacement and then we can see what the issue is.

[Longbow]

Sadly the replacement displays the same faults. Excessive grease on the loco drive chain is the most obvious problem I can see but to clean it off I need to remove the loco body. I have removed the screw under the smokebox but the body is not releasing at the cab end. Perhaps unlike the Hall there is more than one attachment point. Can you help please Dapol?